# Automotive oil changes



## Ashful (Apr 5, 2019)

Conventional wisdom, dad’s era:  Change oil every x,xxx miles (usually 3,000) or 6 months, whichever comes first.

My understanding was the mileage limit was to account for breakdown of Dino oil in that engine, and the 6 months was to remove the blow-by contaminates that cause crank case and valve train corrosion.  Not to mention the chunks of lava rock looking crap that we’d find grown around the push rods and rockers on cars that didn’t get frequent-enough oil changes.

Now today, most of our cars have electronic oil change indicators, which track oil life as a function of actual running conditions.  Others who don’t are doing 7500 or sometimes even 10k mile oil changes that may put their change interval at greater than 12 months!

No issues with breakdown, given modern lubricants, but what about those blow-by contaminants?  Yes, blow-by may be reduced in some modern engines, but it may also be higher in others, and having combustion contaminants sitting in the crank case for periods of a year or more may not be the best thing for your engine.

I drive all of my cars less than 5k miles per year, so I’ve just been doing 6 month oil changes, despite the actual mileage.  Seems cheap enough and quick enough to not really even question, and I’m sure I’ll continue doing just that, but my curiosity is piqued.  How is it suddenly okay to let the same oil sit in your crankcase for indefinite time, maybe even 5 years by the book, if you only put 1k miles on a car per year?


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## therealdbeau (Apr 5, 2019)

Modern rule of thumb is x,xxx mileage (determined by vehicle) or 1 year. I haven't seen anyone suggest leaving oil in there for more than a year. Also, don't forget about the oil filter. It's there to prevent contaminants from getting to the motor.


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## SpaceBus (Apr 5, 2019)

If in doubt, send a sample of your oil to Blackstone Labs. They have a kit you order with specimen containers, etc. After collecting samples, usually from the oil filter, you send it back to Blackstone and they analyze the oil and send you results. They say with modern top tier base stock sythentic oils you can easily go 7,500 if not more miles between changes. I keep it around 7,500 or anuallly. Blowby is trapped in the filter. Only tiny, less than 5-15 microns, pieces of metal stay suspended in the oil, which is why you have to change it. If you don't, the oil breaks down and leaves the tiny metal in your bearings, which will eventually ruin them and your engine. 

If you drive the car hard, I would definitely change the oil seasonally. Even if you don't drive the car hard, it's not a bad idea to change the oil seasonally in a cold climate. Often cold temperatures are harder on the oil than mileage. This is partially due to trying to squeeze much more viscuous oil into tiny bearing clearances in cold temperatures. The other part is just that cold temperatures break the oil down just like hot temperatures.

I'm not an engineer, but I know a lot of engineers and I went to car school at the government's (your) expense.


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## blades (Apr 5, 2019)

the oil itsel;f does not break down, the various additives go south though. turbo units and any thing with variable cam timing systems best to change out every 3k miles . the turbo boost adds more blow by  and the variable timing assemblies have extremely small passages in them that are easily blocked, not to mention the unbelievable tight tolerances in same.


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## SpaceBus (Apr 5, 2019)

blades said:


> the oil itsel;f does not break down, the various additives go south though. turbo units and any thing with variable cam timing systems best to change out every 3k miles . the turbo boost adds more blow by  and the variable timing assemblies have extremely small passages in them that are easily blocked, not to mention the unbelievable tight tolerances in same.



True, it's not literally the oil. I didn't think about VVT/VCT but that's an excellent point. If you have a turbo you should have a catch can. I don't think I've ever seen an OEM application that didn't have some sort of filtered crank ventilation, but perhaps some don't.


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## brenndatomu (Apr 5, 2019)

Ashful said:


> How is it suddenly okay to let the same oil sit in your crankcase for indefinite time, maybe even 5 years by the book, if you only put 1k miles on a car per year?


Its not...most manufactures tell you to change every year minimum, even if the mileage is low.


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## blades (Apr 5, 2019)

most egr systems oem do not have any filtering installed. as to the catch cans unless it it is properly designed - do not help much except to lighten wallet.


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## PaulOinMA (Apr 5, 2019)

I follow manufacturer's recommendations.  I'm on enough car web sites and enough people have posted their oil analyses to show that more frequent oil changes are not necessary.

I use full synthetic.

Both our indicators just came on.  Mine because of 10,000 miles.  My wife's because of one year.

Oil and filters are in the garage.  Will probably do my wife's on Sunday afternoon and mine one day next week.  Also have a cabin filter for my wife's Escape and cabin and and air filters for mine.  Will also remove winter tires and wheels.

Cabin filter for mine takes some contortions to get to. 

Both oils have to meet Ford spec.  My wife's Escape takes 5W-20, and the spec is …-945-A.  Mine is 5W-30, ...946-A.  Can also use the newer Ford B1 spec oil, which had an additional testing specification for LSPI (low-speed pre-ignition).

Both Pennzoil and Mobil 1 are running their rebates now.  I had been buying Mobile 1  Extended Performance, but bought Pennzoil Platinum Full Synthetic this time since the Mobil 1 rebate wasn't up yet.

Rebates …

https://www.pennzoil.com/en_us/prom...56b2lsLzIwMTZuZXdzbGV0dGVyLz9sb2NhbGU9ZW5fdXM

https://mobiloil.com/en/promotion/mobil-promotions/mobil-1-rebate-2019


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## peakbagger (Apr 5, 2019)

Amazon has a full synthetic for quite a savings. Typical synthetics are marketed as premium,folks expect them to be expensive so they price them that way.


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## begreen (Apr 5, 2019)

Rule of thumb is just that. An engine is likely to see all kinds of service. How frequently the oil gets changed should be based on how the car/truck is used and type of engine. I could go 6000 miles of highway only driving on my old Volvo and the oil still looked great. But the same engine put through daily stop and go, cold startups, etc. definitely needed an oil change at 3000 miles. Winter driving is tougher on an engine than summer driving too.


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## Easy Livin’ 3000 (Apr 5, 2019)

This thread really makes me want an electric car.


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## PaulOinMA (Apr 5, 2019)

Friend was manager at a Tesla dealership last year.  Met him and he had a Model X.  Instant acceleration with full electric vehicles.

My wife has a hybrid Ford Escape.  Never thought she'd be driving a hybrid, but she won it at work in 2011.  Likes it a lot.  New Escape will be offered as a hybrid again, and she's interested.


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## blades (Apr 5, 2019)

90k on my 2016 escape 2l turbo  oil gets dirty in 3k   so for me that means changing oil about once a month.  223xxx on my 6.0 - oil runs everything on this unit so changes at 3k are best also . HPOP are pricy and very time consuming to replace. 
likely will need to pull the heads on the 2l because of the egr system loading up the valves and the innards of the turbo with crud.


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## begreen (Apr 5, 2019)

Yes, good reminder. I need to get my truck's oil changed soon.


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## SpaceBus (Apr 5, 2019)

blades said:


> 90k on my 2016 escape 2l turbo  oil gets dirty in 3k   so for me that means changing oil about once a month.  223xxx on my 6.0 - oil runs everything on this unit so changes at 3k are best also . HPOP are pricy and very time consuming to replace.
> likely will need to pull the heads on the 2l because of the egr system loading up the valves and the innards of the turbo with crud.



Wow, lot of miles on a 6.0! I looked for a 7.3 truck last summer but found an unbeatable deal on my 06 Ram.


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## blades (Apr 5, 2019)

04 250 in exceptional condition over all for my area.  unfortunately my 06 250 with 160xxx  body is disintegrating from the red death- luck of the draw I guess.


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## SpaceBus (Apr 5, 2019)

blades said:


> 04 250 in exceptional condition over all for my area.  unfortunately my 06 250 with 160xxx  body is disintegrating from the red death- luck of the draw I guess.


I bought my truck in NC to avoid this issue.


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## Ashful (Apr 5, 2019)

brenndatomu said:


> Its not...most manufactures tell you to change every year minimum, even if the mileage is low.


How many have you specifically checked for this, to have arrived at that conclusion?  I just randomly checked our owner’s manuals from two brands, and our two cars from one brand (Chrysler) did have this, while the other brand (Volvo) did not.  That’s 50% of manufacturers, based on my very limited research.

SRT spec’s 6000 miles or 6 months maximum, sooner if oil life indicator demands it.  That’s with Pennzoil 0W40 full synthetic specified.  The Ram is 10,000 miles or 12 months maximum, this time no synthetic requirement, and again usage-based oil life indicator can override.  Volvo is just 7500 miles, no time limit specified in owners manual or warranty and maintenance manual, and the oil life indicator is only mileage based (not driving style dynamic).

The way it works out, I’m doing that Volvo 3x per year, just based on mileage, but if it was driven like some of my cars...


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## saewoody (Apr 5, 2019)

I run all my vehicles with synthetic oil. Have been doing that for at least 20 years.  They all get the 6 month/6,000 mike oil change the n the spring and fall. Have never run into any oil related issues.  I tend to drive older, high mileage cars. My current stable has a 2001 Chevy 5.3 with 160,000 (had it since 75,000), a 2004 Chevy 6.0 with 190,000, and a 2005 Nissan 1.8 with 187,000.  My 2003 Chevy 5.3 in my last vehicle that got hit and totaled a year and a half ago had over 215,000 on it. Also ran a 97 Ford Explorer from 36,000 to 210,000 (until that got hit and totaled) using the same oil change schedule.

I definitely would not go over a year without an oil change no matter how low the miles were.  But the way I have been doing it has certainly served me well.

And in case anybody needs an oil change, Napa is running a Great oil change deal for the month of April. It you can get regular, high mileage, or synthetic plus their height and oil filter for $22.


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## KJamesJR (Apr 5, 2019)

I was always led to believe...

You can change your oil and leave it indefinitely, that is until you start your motor. As soon as it’s subject to the heat/friction the additives become comprised and begin their slow process of decomposition.

Which is why you should drive it the 5k-10k miles before the years spent or you’re not getting your money’s worth. 

Most synthetics have an indefinite shelf life. Mobil actually puts an expiry date on there’s, think it’s five years, though probably just added for the sake of it.


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## peakbagger (Apr 6, 2019)

My Ford and a lot of other newer vehicles look at the usage of the car to decide when to change the oil. I have to get an inspection sticker once a year for the car and usually have the oil and filter changed without the code flashing. When I or the shop forgets to reset the code its been about three months before the computer flashes a screen to change the oil. I do a lot of highway miles about 20K a year on long day trips. I work from home so not a lot of local trips and even my local trips allows the car to warm up completely which is key to oil life. I use synthetic so I ma not worried about the oil breaking down. The engine will naturally breathe in humidity just sitting there and that humidity gets in the oil and combustion byproducts that leak past the piston rings can form acids in the oil. If the car is run long enough that humidity gets driven off from the engine and other components. Talk to anyone who does exhaust systems and they sell a lot more exhausts that rotted out to low mileage "granny car" then high mileage cars.

Oil should be changed based on hours of operation modified by number of engine starts and number of times the engine is short cycled where it doesn't get to full temperature . If oil analysis is done the number of hours can be stretched a long time. Industrial air compressors don't have combustion but its a pretty intense application. There are (or were 10 to 15 years ago) that offered lifetime guarantees on their industrial compressors if they were operated with a lifetime lubricant which was a synthetic if the owner sent oil analysis reports on a routine basis and added an additive package on occasion when the analysis indicated it.

By the way oil can really get cooked in turobcharged engines as the center bearing of the turbo can "burn" the oil from the heat on the exhaust side when the engine is shut down. My GMC Syclone required Mobil 1 synthetic oil changes to keep the warranty valid as Mobil 1 had much higher temperature it could withstand before the oil failed.  Standard recommendation with turbo engines is let the engine idle for a few minutes to allow the turbo to cool down prior to shutting the engine off. Some folks with high performance engines put separate electric oil pumps that run for a few minutes after the engine is shutdown.


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## WES999 (Apr 6, 2019)

One reason not to wait too long to change your oil, even if you don't drive the vehicle much:
My Ford ranger that I don't drive that often. developed leak in the oil filter, it had rusted through.
It was only luck that I noticed it leaking, was about a quart or so low.

In my daily drivers I change the oil every 5-6K with a good synthetic. I think some of the manufactures 
change intervals are a bit long. The cars with VVT are susceptible to damage from dirty oil.


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## SpaceBus (Apr 6, 2019)

peakbagger said:


> My Ford and a lot of other newer vehicles look at the usage of the car to decide when to change the oil. I have to get an inspection sticker once a year for the car and usually have the oil and filter changed without the code flashing. When I or the shop forgets to reset the code its been about three months before the computer flashes a screen to change the oil. I do a lot of highway miles about 20K a year on long day trips. I work from home so not a lot of local trips and even my local trips allows the car to warm up completely which is key to oil life. I use synthetic so I ma not worried about the oil breaking down. The engine will naturally breathe in humidity just sitting there and that humidity gets in the oil and combustion byproducts that leak past the piston rings can form acids in the oil. If the car is run long enough that humidity gets driven off from the engine and other components. Talk to anyone who does exhaust systems and they sell a lot more exhausts that rotted out to low mileage "granny car" then high mileage cars.
> 
> Oil should be changed based on hours of operation modified by number of engine starts and number of times the engine is short cycled where it doesn't get to full temperature . If oil analysis is done the number of hours can be stretched a long time. Industrial air compressors don't have combustion but its a pretty intense application. There are (or were 10 to 15 years ago) that offered lifetime guarantees on their industrial compressors if they were operated with a lifetime lubricant which was a synthetic if the owner sent oil analysis reports on a routine basis and added an additive package on occasion when the analysis indicated it.
> 
> By the way oil can really get cooked in turobcharged engines as the center bearing of the turbo can "burn" the oil from the heat on the exhaust side when the engine is shut down. My GMC Syclone required Mobil 1 synthetic oil changes to keep the warranty valid as Mobil 1 had much higher temperature it could withstand before the oil failed.  Standard recommendation with turbo engines is let the engine idle for a few minutes to allow the turbo to cool down prior to shutting the engine off. Some folks with high performance engines put separate electric oil pumps that run for a few minutes after the engine is shutdown.



Turbos are hard on cars. The heat thing isn't specific to M1 synthetic. Some racing engines have such tight tolerances they must be fed hot water and oil just to start them. The higher number on the oil weight also determines temperature protection for the oil. Cars that see the track use a 40 - 50 weight oil because it acts like a 20 weight at track temps. Diesel engines run hot so 5W40 is about the standard, but that's also what I used in all of my performance engines and my bikes. Oil made for diesel engines is usually the best oil, so I put Rotella T6 in basically everything, especially turbo engines.


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## KJamesJR (Apr 6, 2019)

SpaceBus said:


> Turbos are hard on cars. The heat thing isn't specific to M1 synthetic. Some racing engines have such tight tolerances they must be fed hot water and oil just to start them. The higher number on the oil weight also determines temperature protection for the oil. Cars that see the track use a 40 - 50 weight oil because it acts like a 20 weight at track temps. Diesel engines run hot so 5W40 is about the standard, but that's also what I used in all of my performance engines and my bikes. Oil made for diesel engines is usually the best oil, so I put Rotella T6 in basically everything, especially turbo engines.


+1 For Rotella T6


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## Ashful (Apr 6, 2019)

KJamesJR said:


> Which is why you should drive it the 5k-10k miles before the years spent or you’re not getting your money’s worth.


I understand your reason for saying this, but I’m not really worried about getting my money’s worth, it’s not expensive enough to even give a second thought.   I change both of my vehicles twice per year, because one of my vehicles actually specified that, I probably have 2000 miles on the one and 2500 miles on the other.  I change my wife’s 3x per year, right around the specified 7500 miles.  

I find Amazon’s Subscribe and Save is a great tool for this, and anything else you need to remember to do x times per year, like electric toothbrush heads.  The oil filters are scheduled to show up on my prescribed schedule.  When they arrive, I swing by Walmart for some oil, and do the deed.


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## KJamesJR (Apr 6, 2019)

Ashful said:


> I understand your reason for saying this, but I’m not really worried about getting my money’s worth, it’s not expensive enough to even give a second thought.   I change both of my vehicles twice per year, because one of my vehicles actually specified that, I probably have 2000 miles on the one and 2500 miles on the other.  I change my wife’s 3x per year, right around the specified 7500 miles.
> 
> I find Amazon’s Subscribe and Save is a great tool for this, and anything else you need to remember to do x times per year, like electric toothbrush heads.  The oil filters are scheduled to show up on my prescribed schedule.  When they arrive, I swing by Walmart for some oil, and do the deed.


+1 For Walmart. They have the lowest prices on brand name oil. 

Expense is a matter of opinion I suppose. I go through 6 quarts of synthetic Shell Rotella and OEM filter 3 times a year in just my vehicle alone. That’s about $45 a pop or $135/year for one vehicle. I do my wife’s in the same intervals although hers are half the price.

I’d be curious to see how much degradation has occurred in oil that’s been only been used lightly within a year. Might only be minuscule.


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## rowerwet (Apr 6, 2019)

Work with a guy who never changes his oil, just the filter, it's a Saturn he bought new,  and it continues to run just fine.

Personally I use amsoil,  with a 25,000 mile/ 1 year interval. Been doing it almost 20 years, none of my cars really use oil and no engine trouble. 
My commute is 35 miles each way, 4 days a week,  my wife's van goes about 40 miles a week.


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## Ashful (Apr 7, 2019)

KJamesJR said:


> I’d be curious to see how much degradation has occurred in oil that’s been only been used lightly within a year. Might only be minuscule.


I agree, the degradation is likely minimal, at that point.  I think the time-based interval is all about flushing out combustion contaminants, it has nothing to do with degradation of the oil.


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## PaulOinMA (Apr 8, 2019)

Did oil, oil filter, air filter, and cabin pollen filter yesterday on my 2014 Escape.  *10,000 miles,* 9 months for the oil.  Also removed winter wheels/tires and put on all-seasons.  Cabin filter is a pain to get to under the dash in the center.

Also did the oil, oil filter and cabin filter on my wife's 2012 Escape.  *1 year,* 5,600 miles for the oil.  No belly pan and a little more ground clearance.  Don't need ramps like I do with mine.  Also removed winter wheels/tires and put on all-seasons.

Both full synthetic oil.  Have three full 5-quart jugs of used oil to drop off at Autozone this morning.  Can't believe we used to dump waste oil along the rock walls in the yard when I was a kid in the 1960s to kill vegetation.  Crazy the way things were back then.

Though I'd be more sore today from all the up-and-down on the ground yesterday.


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## SpaceBus (Apr 8, 2019)

Ashful said:


> I agree, the degradation is likely minimal, at that point.  I think the time-based interval is all about flushing out combustion contaminants, it has nothing to do with degradation of the oil.


Most of that stuff ends up in your filter anyway. It's the less than 5 micron pieces of metal suspended in the additives you have to worry about.


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## Ashful (Apr 8, 2019)

SpaceBus said:


> Most of that stuff ends up in your filter anyway. It's the less than 5 micron pieces of metal suspended in the additives you have to worry about.



Really?  That really surprises me.

I just dropped the sedan off for inspection this morning, so I took a peak at the mileage before I turned it in.  Purchased March 2016, and it has had six oil changes in 11,917 miles.  I recall the first was at 500 miles, so removing that one and backing out the mileage since the last oil change, I’m changing oil roughly every 2075 miles.  Full synthetic, Pennzoil 0W40, as specified by manufacturer.

Car has catch can, and uses the most expensive oil filter I’ve ever seen.  Something about a special bypass, I don’t recall the details.  Again, just following manufacturer recommendation, I just always hit the 6 months maximum before the mileage maximum.


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## Fiddler (Apr 8, 2019)

I do every 5K miles on my, my wife's and my two daughter's cars. Cost me about $25 per car and takes me around a half hour per vehicle, including checking tire pressure, fluids, etc. Seems like a small price to pay to keep the vehicles running and know the girls are driving safe vehicles


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## SpaceBus (Apr 8, 2019)

Ashful said:


> Really?  That really surprises me.
> 
> I just dropped the sedan off for inspection this morning, so I took a peak at the mileage before I turned it in.  Purchased March 2016, and it has had six oil changes in 11,917 miles.  I recall the first was at 500 miles, so removing that one and backing out the mileage since the last oil change, I’m changing oil roughly every 2075 miles.  Full synthetic, Pennzoil 0W40, as specified by manufacturer.
> 
> ...



Charger or 300? I used to have a six speed 420 RWHP SRT8 6.1 Challenger. It cost less to have to dealer change the oil vs myself. I'd love an SRT8 Cherokee of any year for a DD up here, but the upkeep is a bit high. 

The bypass is for startup to deliver oil directly to the valve train instead of going through the filter on a cold start. The additives are there specifically to catch the sub 5 micron particles that the filter can't get. The bits get suspended where the can't damage bearings and such.


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## blades (Apr 8, 2019)

well that's the theory anyway.


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## Ashful (Apr 19, 2019)

SpaceBus said:


> Charger or 300? I used to have a six speed 420 RWHP SRT8 6.1 Challenger.


6.4L 8-speed Charger.  485 RWHP.  Not the fastest car I've owned, but it sure as hell gets the kids to school on time.


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## zrock (Apr 21, 2019)

Working in different automotive shops iv seen the aftermath of just changing filters. U may be lucky and it will never happen to you.. I do mine every 5000-7000km full synth.. oil is cheap especially when you plan ahead and get it on sale. I would rather spend a few $$ on oil every year then $5000 on a engine job.. I could do oil changes for the rest of my life and still have change left over for the price of a engine job..LOL


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## blades (Apr 21, 2019)

Got to watch out on after market filters some do not fit correctly in the canister type systems


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## Seasoned Oak (Apr 21, 2019)

Ashful said:


> Full synthetic, Pennzoil 0W40, as specified by manufacturer.


Im sure Their(PennZ) Synth oil is better than their conventional oil was. When i worked in an engine rebuild shop(in the 80s) the most common oil used in the engines we got in to rebuild was PennZ and Quaker state.Lots of sludge in those engines. Was told it was due to the parafin(waxy) base.  My brother also used that oil exclusively and changed it often. Most of his vehicles started to blow smoke after awhile. Fast forward to today and synthetics seem to all be very good quality. Just found out the Camaro 8Cy calls for 9 quarts of oil. Almost twice as much as normal.


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## SpaceBus (Apr 21, 2019)

Seasoned Oak said:


> Im sure Their(PennZ) Synth oil is better than their conventional oil was. When i worked in an engine rebuild shop(in the 80s) the most common oil used in the engines we got in to rebuild was PennZ and Quaker state.Lots of sludge in those engines. Was told it was due to the parafin(waxy) base.  My brother also used that oil exclusively and changed it often. Most of his vehicles started to blow smoke after awhile. Fast forward to today and synthetics seem to all be very good quality. Just found out the Camaro 8Cy calls for 9 quarts of oil. Almost twice as much as normal.



The huge oil capacity is really for cooling and sump volume when at the track under high g loads that would starve a smaller system.


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## blades (Apr 21, 2019)

9 quarts , how about 4 gallons on my diesel and after market pans hold more.


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## SpaceBus (Apr 21, 2019)

blades said:


> 9 quarts , how about 4 gallons on my diesel and after market pans hold more.


Of course there's always that. What sump do you have? I wouldn't be sad for more capacity for my Cummins.


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## blades (Apr 22, 2019)

4 gal is stock  deeperpans avaiable for 6.0--6.7


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## Highbeam (Apr 28, 2019)

blades said:


> 4 gal is stock  deeperpans avaiable for 6.0--6.7



Just last weekend I used 15 quarts of synthetic 5w-40 in my dd pickup, 7.3 diesel. Just the oil filter holds 2 quarts. 

Our new import requires 0-20w and I plan to start and stay with mobile 1 synthetic. Hope it’s still good stuff. Seems prices are all about 20-23$ per gallon for all name brand oils now.


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## maple1 (May 4, 2019)

Our 2006 Civic with 510,000kms, and 2007 Pilot with 270,000kms, have lived by the maintenance minder and dealer oil changes since new. That interval is in the area of 10-12,000kms. Our 2017 Civic was a bit over 15,000kms before it told us it was time for the first one.


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## CaptSpiff (May 4, 2019)

maple1 said:


> Our 2006 Civic with 510,000kms, and 2007 Pilot with 270,000kms, have lived by the maintenance minder and dealer oil changes since new. That interval is in the area of 10-12,000kms. Our 2017 Civic was a bit over 15,000kms before it told us it was time for the first one.


So you've driven your '06 Civic about 22K miles per year, with oil changes about every 7K miles, or about 3 times a year.
That really is the "sweet spot" for oil usage in modern ICE vehicles.

As others have mentioned, there's two things at play that drive oil change intervals:
1. The wearing out of the EP (extreme pressure) additives in the oil, typically 7-10K miles.
2. The accumulation of acid sludge, from blow-by gases & moisture in the lower part of the engine.
Of the two, most drivers reach the latter before ever needing to worry about the former.

You are driving enough to fully heat your engine and allow the internal moisture to fully boil off. That minimizes the opportunity to form acidic sludge in your engine. Great going, short trips which barely allow the engine to warm up require more frequent flushing of the oil to get out that bad stuff. The most at risk are those who drive short distances and only do one change per year.


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## Ashful (May 5, 2019)

CaptSpiff said:


> So you've driven your '06 Civic about 22K miles per year, with oil changes about every 7K miles, or about 3 times a year.
> That really is the "sweet spot" for oil usage in modern ICE vehicles.
> 
> As others have mentioned, there's two things at play that drive oil change intervals:
> ...



Excellent post.   This is everything I was trying to say above, only more expertly stated.


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## semipro (May 5, 2019)

Based on what I've learned here and in a prior thread I've switched over to full synthetic oil for my vehicles Castrol in my case.. My hesitancy was based on the comparative price of synthetic versus natural.and my (mistaken) perception of those costs. I remember with Mobil 1 came out and the cost difference was considerable.  A post by @Ashful convinced me that for a relatively small additional investment I could run synthetic now. I bought in. I'm willing to pay a little more for a lot. 
Now I'm trying to use up the natural stuff in my machinery and expect to switch over to synthetic on everything once that's gone. 
Sometimes "natural" doesn't mean better.


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## fbelec (May 8, 2019)

i got a old 2001 grand marquis 236,000 miles on the 4.6 v8. i bought it from my friend and asked him why didn't you tell me that it was blowing oil. when i changed the oil i threw in conv. oil and was going thru a quart every 4 to 500 miles he asked what i was using for oil and he said use synthetic when i did it stopped. i change it at 3000 miles and at that point is when it is down a quart. it's funny how these so called catch cans are starting to be made for spec vehicles from the factory. i bought one about 30 years ago from a back of a magazine called the condensator and been using on my vehicles since it goes inline with the pcv line and filters out the junk that is flowing out the vent then back into the manifold. it is still being sold today. when i added it the oil stayed cleaner and fuel mileage went up. first car i had it on was my 76 lincoln town car. 5500 pounds and a 7.5 liter engine. no overdrive back then. mileage went from 8 to 9 city and 15 highway to 13 city 23 highway just by installing a catch can that condensed the oil fumes that went into the motor so it was filtering my blow by. got rid of that motor with 425,00 miles on it when at the time cars in that era were junk at 125,000 miles. changed the oil every 3000 and because of the condensator the oil was still see thru. this should be on all cars.


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## Seasoned Oak (May 8, 2019)

CaptSpiff said:


> The most at risk are those who drive short distances and only do one change per year.


That would be me. 4 vehicles and put about 7000 miles per yr on all 4 combined. Lots and lots of short trips on the 2 oldest. Change oil once a yr. If i am doing any damage to these vehicles thru infrequent oil changes after 150k to 200k on the 2 oldest ones,23 and 25 yrs old, they are already at or near the end of their useful lifespan. Any additional lifespan left in the engine vs the rest of the vehicle is useless at this point. I do use synthetic in all and all run fine with zero engine problems. Been doing this for 25yrs, never an engine or trans failure or internal engine repair needed. Im not posting this to recommend it ,just my personal experience and i would probably change more often in a classic vehicle i wanted to keep indefinitely.


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## begreen (May 8, 2019)

We are fairly low miles also with most of our trips being local. Why I love our Volt. All local miles are electric. Distance driving is on the ICE where it gets a chance to fully warm up.


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## PaulOinMA (May 8, 2019)

begreen said:


> We are fairly low miles also with most of our trips being local. Why I love our Volt. All local miles are electric. Distance driving is on the ICE where it gets a chance to fully warm up.



Two neighbors were senior executives for a chemical company.  Their office was a couple of miles from our homes.  One drove a 500-h.p. BMW M6 convertible.  The other had an Audi A8L, but got a Volt after that.  Said it was great for his commute.


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## Seasoned Oak (May 8, 2019)

begreen said:


> We are fairly low miles also with most of our trips being local. Why I love our Volt. All local miles are electric. Distance driving is on the ICE where it gets a chance to fully warm up.


This is why i would love a gas electric pickup truck with a range extender. A Volt style truck.  All those trips i can measure in tenths of a mile, no warmup not to mention horrendous MPG. Plus in my line of work im in the drive up at the bank almost daily. Sure i can keep turning the engine on and off to move thru the line but low speed electric propulsion would solve that too.


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## Ashful (May 8, 2019)

fbelec said:


> it's funny how these so called catch cans are starting to be made for spec vehicles from the factory. i bought one about 30 years ago from a back of a magazine called the condensator and been using on my vehicles since it goes inline with the pcv line and filters out the junk that is flowing out the vent then back into the manifold.


Naturally-aspirated cars today really don’t benefit much from them, there is so little crankcase flow thru the PCV valve.  Where you’re seeing them on factory vehicles, it’s likely cars with big turbos or superchargers, there is good justification to have them there.

I have one installed on a modern naturally-aspirated vehicle that I drive fairly hard, and it doesn’t even collect a half ounce in 3000 miles of hard acceleration driving.  That same can on the supercharged version of my car will fill completely full (half quart?) in just 2000 miles.



PaulOinMA said:


> Two neighbors were senior executives for a chemical company.  Their office was a couple of miles from our homes.  One drove a 500-h.p. BMW M6 convertible.  The other had an Audi A8L, but got a Volt after that.  Said it was great for his commute.



I drive a 500 hp car 7 miles to work, each day.  Given the displacement of that engine and the short commute, it isn’t even at full operating temperature when I park and shut it down.  Mileage is horrendously bad, as a result, think close to 10 mpg.  It gets mid-20’s on longer drives.  I could see replacing it with a Tesla... but never a Volt!


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## begreen (May 8, 2019)

Ashful said:


> Naturally-aspirated cars today really don’t benefit much from them, there is so little crankcase flow thru the PCV valve.  Where you’re seeing them on factory vehicles, it’s likely cars with big turbos or superchargers, there is good justification to have them there.
> 
> I have one installed on a modern naturally-aspirated vehicle that I drive fairly hard, and it doesn’t even collect a half ounce in 3000 miles of hard acceleration driving.  That same can on the supercharged version of my car will fill completely full (half quart?) in just 2000 miles.
> 
> I drive a 500 hp car 7 miles to work, each day.  Given the displacement of that engine and the short commute, it isn’t even at full operating temperature when I park and shut it down.  Mileage is horrendously bad, as a result, think close to 10 mpg.  It gets mid-20’s on longer drives.  I could see replacing it with a Tesla... but never a Volt!



Some Ford F150 folks say their gas mileage actually decreased with a catch can added to their newer F150s. .


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## blades (May 8, 2019)

that makes some sense as the programing is optimized for reburn .


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## fbelec (May 9, 2019)

right now i have my condensator hooked up to my 04 e350 stretch van with a 5.4 v8. when i didn't have it the truck was 10 to 11 mpg after hookup there is two ways to run it third line comes into it with cool fresh air or plug the 3rd line and it still does it's job. with this truck i plug the third line and it gets better mpg i run 12.5 to 13 with it on. my last truck i had it running on a 1996 e250 with the last year of the 5.8 351w. it boosted the mileage from 11 to 12 to 14 to 15 mpg and had to dump the jar every other oil change. with this truck it doesn't collect much in the jar but mpg is slightly better. but this truck is running synthetic oil and the old truck was running regular castrol oil 10w40


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## fbelec (May 9, 2019)

also the man who invented the condensator said that they work well with turbo motors and depending on the size of the motor that two would work better like the ford 3.5 TT that has two pcv lines. and over the road diesel would need two also. he advertises that these condensators would double engine life.


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## blades (May 9, 2019)

from what I have read on  DI eng. the problem with EGR is it collects on valves and turbo fins basically getting cooked in place like a glass coating. some of the new eng have addressed this with a combined direct and indirect system there by washing the valves a bit, turbos still get coked up. pretty much a 100k pull  the heads and turbo, blast clean- very expensive maintenance.


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## SpaceBus (May 9, 2019)

blades said:


> from what I have read on  DI eng. the problem with EGR is it collects on valves and turbo fins basically getting cooked in place like a glass coating. some of the new eng have addressed this with a combined direct and indirect system there by washing the valves a bit, turbos still get coked up. pretty much a 100k pull  the heads and turbo, blast clean- very expensive maintenance.



Yes, valves and turbos get loads of varnish buildup in  a DI engine. Most MFGs suggest a walnut media blast on the valves. I don't know about turbos, maybe they just replace them now? Either way a filtered catch can prevents most of the issues. Everyone I know that races on track or autocross (I was one of these folks as well) uses a catch can. Some are as rudimentary as putting a breather filter on the crank intake side and a tube into an empty soda can for the pressure release side while capping the old inlet on the intake. Old cars just had a venturi off the engine and the oil just went on the ground.


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