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Oil leak that is driving me nuts I have a revmaster and I been tryin to track down this oil leak for a while now , it seems as tho it's leaking from bewtween the cylinder and the head , the other day I was changing the oil , and adjusting valves , and while I was turning the prop by hand to adjust the valves , I noticed oil dripping at a good rate , I can't seem to see we're cause the baffles and other stuff , any ideas. We're , I was thinking the lower head bolts oil is goin bye it , but I retorqued the head and sealed under the washers and it is still leaking , I don't know what else to do I also have a small leak coming from one of the case nuts that bolt the block together ,
Adam Simmons

As others have mentioned in similar posts, two strategies I have seen used by experienced A & P's.

One is to completely clean the engine with the correct material so it does not have any oil on it. Start it up, check it. If required, fly it very briefly. This should give you a good indication of the source.

Second strategy is to use the same cleaning technique and then put some white powder on the block to see where the leak is.

If you do a search on this forum there have been previous discussions on this subject.

Good luck and let us know what you find!


Robbie Culver
Sonex 1517
Chicagoland
Tails and Wings complete - finishing fuselage.
N1517S reserved

It looks to me like it's leaking we're the cylinders go into the case , I cleaned the whole engine with brake clean , and let it run , it is seeping pretty good from around the seal , also I notice my breather there is a lot of oil coming out of it , and into my overflow can , an it was leaking from the bottom o ring on my oil over flow can , I replaced that o ring and that is all set , I also retourqued the heads abouts 5 hours ago and it's still leaking oil ,

Is there any sealant where the cylinders go into the case? That's where the spacer shims go to set engine compression and the engine manual says that a sealant is needed at the cylinder base and over said shims during assembly.

I hate to say it, but if that's the case you may need to pull the heads and then pull out each cylinder, one at a time, just far enough that you can reseal that area and those shims before putting the cylinder back on, the heads back on, and re-torque the heads.

Well after I went home after work and tought about this , and was thinking i can't fly till next week because I'm on call 24 hours a day for the next , I will pull this all apart and fix it and be done with it. Seeping oil , so I went back to hanger and started to pull head off and all the other small time consuming things , sheet metal , exhaust , intake , so at some point I see orange rtv around the base very , very little but it's there , so Tomorow I was goin to completely remove head and slide cylinders up one at a time just enuff to get in there and clean and re seal with yamabond 4 , awesome stuff btw , without taking the pistons out of the cylinders , also on mine there is no metal spacers , I have a revmaster 2100 , so that is my plan also I had two of the case nuts seepin also , I removed those and cleaned and put very little yamabond and retourqued , I am hoping to be all set , I am very nervous as to why they don't use head gaskets or base gaskets on the cylinder to case , just sealant , and use nothing on the head to cylinder , hope it works
Adam Simmons