Rotax 250-010 Oil tank Gasket Ring

I have been concerned for some time that the oil tank gasket rings that I have on hand (from Lockwood) are different from some that I had ordered several years ago. Specifically, the original gasket rings had a fiber insert inside the copper "C" ring. To clarify, here is a picture. A used ring with the fiber insert is on the left and a new ring with no fiber insert in on the right:


You can see that when the ring with the fiber insert flattens out it self centers and there is no need to make sure it is centered when you torque the drain plug. I also think that the fiber makes a positive seal. I have used about 5 or 6 of the ones with the fiber insert and never had one leak. On the other hand the ring without the fiber insert will not self center. I just removed one like the one on the right that was off-center and seeping and getting an oil streak on the plane belly. That is really annoying.

When I received these rings without the fiber, I emailed Lockwood and asked what was going on, never received an answer. After just doing an oil change, I discovered the seeping ring and also read Rich's cheapskate thread where at least one other person had found a seep with what I think is the "wrong" gasket ring.

I emailed the help desk at CPS asked if there had been a change in this gasket ring and got an answer back right away that "No, there had not been a change" and that I must have gotten the wrong part. Unfortunately right now CPS is out of stock on these so I have not been able to order some gasket rings from them to see if they are the "right" part. I must say though, I do appreciate that CPS promptly answered my email.

I haven't finished researching this and am posting now without all the complete data because the subject is hot right now in the "Cheapskate" thread. I'll post more when I find out more.

If other's out there have been having specific experience with this please post here.

Glad you pointe this out.

First, I am glad you noticed this Tony - I though I was doing something wrong when I noticed that previous installations of the crush washer would not appear centered after I torqued the bolt. Thought I was doing something wrong (never saw any oil leaks however.)

BTW - Didn't you install one of those quick release drain plugs on your oil tank that eliminates the need to replace the copper washers at oil changes?

Yes, the leaking gasket ring was on the quick drain

Tony, I haven't had a washer with the fiber insert but I can confirm that I did have an issue with the crush washer leaking after removing the OEM one and replacing it with another one at the 25-hour oil change. It was a very slow seepage, so I did not find the issue until yesterday when I took the lower cowl off as part of the annual inspection. I did not notice that the washer was much out of center if it was I was wondering if there was a better way of ensuring a leak-free seal in that hard to reach spot.

Bender has sage advice here.

I concur

I have had the same issue with the new ones too, from Lockwood. Thanks for the info.

Loctite

Not to diminish the wonderful value of Loctite but...it does change torque values. Sometimes that matters, sometimes its does not.

Pete,

I can see how Loctite would increase breakaway torque when disassembling a loctited fastener which could overload the shank of a bolt. Are there other issues?

Rich

I'll try again - -

Put a small amount of 'blue' on the cleaned/dried threads of the plug and base threads. Put it in with only a small amount of torque. ( slightly more than finger tight ). Safety wire. FORGET ABOUT IT ! You are doing no damage to the washer. You can re-use it for ever. Actually don't even need the washer, but it makes the plug stop in a good position.