Sthil 260 Bar Oil Leak

[xman23]

I opened the saw case today, and found the saw sitting in a lot of oil. Not the normal amount you find that runs off the bar. This looks like most of the bar tank. The tank had a little oil left in it, but not much. The cap looked fine. And I don't think it could loose all the oil from the cap. The saw is almost 20 years old, lightly used. I use the thick Sthil bar oil. The oil feed adjustment is full on. I didn't refill it, I'll do that when I need to use it.

Any one have this happen? Any idea what the issue is?

One comment. The Sthil case is a home run. On a good day chain saws are oily, smelly beast. The case makes containing it all effortless.

 

[Tar12]

This is the first place to look if your cap is ok...

If the unit continues to seep oil after a few days, the problem may be the vacuum relief valve located in the side of the engine housing between the oil output hole and the bar stud(s). This valve has an internal spring and ball type arrangement with the ball pressed against the vent hole of the casing of the valve, when the tank develops a vacuum from the normal process of the oil being pumped out. The ball is pulled away from the hole, allowing air to enter into the tank and break the vacuum so that oil can continue to flow to the bar and chain assembly. Once the vacuum is relieved, the spring pushes the ball back against the hole of the valve casing. Sometimes debris may become trapped between the ball and the hole. This would cause the oil to keep "weeping" because there must be some measure of vacuum in the tank to keep the oil from flowing freely once the unit is shut down. More often than not, all one needs to do is to take a small pin or needle and push it into the hole of the valve (identifiable as a small silver disk with a small hole in the center) about 6 or 7 times to loosen the debris. This should re-seal the orifice and keep the oil from seeping from the output hole when the saw is stored.

One other thing is this a split case saw? The gasket maybe bad as well....I would clean it up well and leave the side cover off and locate the source of the leak..

 

[jetsam]

Last time I found a saw in a puddle of oil I hauled it into the shop and put it on the bench to tear it down.... and the filler cap was loose.

In addition to what Tar12 said, there may be an O-ring that seals the hole where the oil line goes into the oil tank, so have a look there too.

 

[Tar12]

Last time I found a saw in a puddle of oil I hauled it into the shop and put it on the bench to tear it down.... and the filler cap was loose.

In addition to what Tar12 said, there may be an O-ring that seals the hole where the oil line goes into the oil tank, so have a look there too.

Forgot about that seal....had one go out on a 036...the line itself might be cracked...

 

[CincyBurner]

I had issue before with bar oil leaking. Like Tar 12 mentioned issue was with spring-loaded ball valve sticking.
Pin loosening the ball did the trick.

Stihl ball valve fix​

 

[xman23]

Thank you!! Excellent info, I'll get working on it.