Oil leak - or blow by????

[Drippy]

Well I better not tell my buddy we need to pull the prop again:-).

Is leaking only airborne - or I assume higher MAP commonly associated with a prop seal leak?

We used a single piece seal - I cleaned like crazy to include with a pick - the grove was clean and used emery cloth on the shaft - it was clean.

We then used the prescribed DOW 737 sealant.

We did not use the prescribed tool to stretch it, but heated the seal and it pulled over the prop hub fairly easily - inspecting it prior to installing the spring and putting it in place it appeared undamaged.

Prior to pulling the prop again - I might try putting some foot powder on the visible portion of the case below the prop seal to see if I get any oil. - thoughts?

[flysrv10]

Originally Posted by Drippy

Well I better not tell my buddy we need to pull the prop again:-).

Is leaking only airborne - or I assume higher MAP commonly associated with a prop seal leak?

We used a single piece seal - I cleaned like crazy to include with a pick - the grove was clean and used emery cloth on the shaft - it was clean.

We then used the prescribed DOW 737 sealant.

We did not use the prescribed tool to stretch it, but heated the seal and it pulled over the prop hub fairly easily - inspecting it prior to installing the spring and putting it in place it appeared undamaged.

Prior to pulling the prop again - I might try putting some foot powder on the visible portion of the case below the prop seal to see if I get any oil. - thoughts?

Looks like you have done good. However, I had one mechanic tell me to heat the seal in hot oil. That destroyed the seal. Might not be your case.

I noticed oil on top of the intake plenum and replacing the seal fixed it.

I don't know about foot powder but the spray powder(?) designed for detecting leaks and sold at aircraft shops stay on the surface for a long time.

[wilddog]

I heated that seal in hot water and used the proper tool. Went on easy. Heard of the hot oil trick but as afraid the glue would not bond. If your seal was leaking, most likely it left oil all over the engine and that will drip off for a while unless you can clean it off.

[Drippy]

We used hot water as well - let it sit at a low boil for about 20 minutes or so.

I would hate to pull the prop again - but really want to solve this - my other wonder is do I need to go with an over sized seal - not sure how I tell? Reading it sounds like that is a major - crack the case type of event.

[bbsdad]

Problem is these are air cooled engines. The air can massively effect were the oil goes once it leaks out. I replaced 2 good crank seals trying to fix a leak. Drops of oil on front bottom cowl and running along case split on bottom. Eventually found the leak to be the vacuum drive seal. Oil would leak from the vacuum drive seal, then pass forward past the baffles along the case split and run alll the way forward to the front seal. Then after shutdown drip on the cowl and run back along case split bottom. I hade tryed the talk trick, pressure test. Etc... Finally found it just by chance. Replaced the vacuum drive seal and it never leaked agin. Fought this helps but just an old a&p’s story. Lesson learned oucums Razor doesn’t aloes apply.

[Thor RV10]

I’ve been adding a quart every 10 hours and ignoring oil on the belly, plus very small pool after sitting more than two weeks. Any thoughts on my inaction? New 540 890 Hobbs

[Drippy]

We tried the UV dye this weekend with a good result - I had a significant leak from one of the push rod covers on my #6 cylinder. The leak was the first push rod aft of the oil fill/dip stick which probably helped to mask the source. But under the UV we could see it was a pretty significant leak around the green push rod cover gasket. We replaced the gasket and added some tite seal. I haven't had a chance to run it but hope to get up there one night this week and I will share the results with everyone.

Thanks once again to everyone for the great suggestions - I think "we" may have solved this . . . knock on wood.

[Drippy]

Just wanted to follow up and thank everyone - especially my FSO RV10 stablemate for all the help. The Oil leaks on 95VT are officially fixed.

Yes you will note the plural. I had a leak from the inboard-forward push rod cover on #6, from the magneto cover plate, and a very slight leak from the oil filter adapter and one of the case through bolts - the one that has the forward hanger integrated. A replacement seal, some tightening and a generous application of tank sealant seems to have done the trick.

I have another 10 hours on this oil until it is time for a change so I will continue to peak under the cowling after dark to see if the UV dyed oil shows up anywhere else but it looks good. [vigorous knock on wood]

Thanks again for all the help.