Oil Leak on Right Front Cylinder Head

Hi Mark,

I have owned a CT for 1500 hours and have almost 2K hours in them. Two things here. In your picture I still see a drop of oil on the valve cover and oil on the plug wires. Just because you changed the "O" rings doesn't mean the problem is solved. I have seen and heard of many including my own CTSW that had an oil ooze on the bottom of two valve covers. I repleced my "O" rings 4 times, I lightly sanded the valve cover face to remove any high spots or imperfections. I tried using Loctite 598 on the valve covers / "O" rings and it helped on 1-2 and some it didn't.

First you need to pin point the leak. Any speculation is just that and you may look for a long time or like you have tried and fix the wrong thing. The two most most common areas for that oil leak is the bottom of the valve cover and the bottom of the gearbox and the incoming air flow pushes it back on everything else making it look like it came from somewhere else and at times leaving the leaking area clean. The gearbox would be my last choice since I don't see any oil under the cylinders and all over everything else. This particular leak can make a big mess. Not the likely culprit.

Here is the solution. Clean the area underneath around the cylinders and under the gearbox between the oil pump and bottom of the gearbox real good. You can use some carb cleaner spray to wash out the tight areas. Buy some Dexenex Foot Powder spray. It is white when sprayed on and sticks until you wash it off. Then go fly for 15+ minutes. ANY little ooze or leak will stand out against that white powder like a red flag and makes your diagnoses easier. 

Spray under each valve cover edge and just under the gearbox in that space between the oil pump and gearbox bottom. If that space is totally dry from any oil residue I seriously doubt any oil is leaking there. The gearbox isn't the likely leak anyway, but since you have the spray might as well rule it in or out.

I just had a guy with a 912iS engine that swore oil was coming from some place and wanted to come see me. I would have had to pull his engine. Before he did that and he spent a bunch of money fixing something that we were unsure of I had him do the same thing with the foot powder. Found out it was coming from where the starter enters the engine. Then told him to tighten the nuts and he found them loose.  He tightened them and problem solved. Cost was only for the foot powder and knowing EXACTLY where the leak was was the key. Air flow through the cowl has a way of making us thinking leaks are coming from somewhere else. 

Hi Roger,

I've the same issue on a 912S3 and used the power "thrick" and it seems the is coming for the pushrod tubes where they connect to cylinder head. Any special glue or suggestion to apply, to avoid taking the cylinders heads out?

Thank you in advance,

We had the same problem with the covers. Grinding the covers helped. The easiest way to straighten the covers on a flat straight glass surface using 400 sandpaper