Pesky engine oil leaks

Paul Eastham · #1 12-22-2007, 10:56 PM

Hey gang,
Just uncowled for oil change #3 on my Aerosport O-320 and found several new oil leaks that have appeared between 40 and 65 hours. I'm curious if anyone has had experience with leaks in these spots, and are leaks like these inevitable on threaded fittings somewhere on the engine? All the rental birds I ever flew sure seemed to have em...

#1 seems to be leaking from the threads of a stud where it emerges from a nut. Sad to say I do not know what this thing is for -- forward upper left side of crankcase. Torque seal still intact from aerosport, just now I put a 10" wrench on it and couldn't tighten it further.

On the plus side, I can keep an eye on this one without decowling. Looks like it has leaked about 15 drops of oil. Made a nice mess against the back baffle wall.

#2 is the oil quickdrain, leaking around the threads. Was installed with ez-turn, and cranked it in as hard as I could with a 1-foot wrench. Not enough?

asav8tor · #2 12-22-2007, 11:35 PM

I'm sure you will get some good info quickly but before you do.... STOP wrenching stuff as tight as you can. You are going to strip, break, or otherwise cause yourself more problems unless you know for sure how much force can be applied. This is not the case where.... "when in doubt, get a bigger wrench".

I'll stop now and let the gear heads chime in.

Paul Eastham · #3 12-22-2007, 11:41 PM

In my defense, I do believe I looked up the allowed torque for such a large NPT (the oil drain) and decided that it was more than I could apply -- since it was off the scale of a torque wrench that I'm just barely able to max out.

On the stud, #1, it was already torqued more than I could manage with standard length wrenches. I didn't budge it.

Norman CYYJ · #4 12-23-2007, 01:05 AM

Sometimes the places where you think the oil is leaking is not the place it is actually leaking. There is a lot of air movement in there and the oil could be coming from somewhere else and just collecting where you see it. The oil leak at the drain plug is probably weeping a bit. Call Bart and ask him, he'll be more than happy to help you.

Geico266 · #5 12-23-2007, 01:40 AM

What kinda of thread sealing are you using? We all know teflon tape is a nono. How about the TFE liquid paste plumbers use?

AlexPeterson · #6 12-23-2007, 08:02 AM

Regarding the quick drain, mine spits a little through the valve. After oil changes, I stuff a rolled up paper towel up inside to remove oil below the valve. I see oil in the threads above, but I've convinced myself that vibration causes some leakage through the quick drain valve. I always have a few drops generally below this area. When the cowl is off, I'll stuff another paper towel inside, and there is always oil. It is not quite a big enough nuisance to do anything about.

Paul Eastham · #7 12-23-2007, 09:07 AM

Quote:

Originally Posted by AlexPeterson

Regarding the quick drain, mine spits a little through the valve. After oil changes, I stuff a rolled up paper towel up inside to remove oil below the valve. I see oil in the threads above, but I've convinced myself that vibration causes some leakage through the quick drain valve. I always have a few drops generally below this area. When the cowl is off, I'll stuff another paper towel inside, and there is always oil. It is not quite a big enough nuisance to do anything about.

Thanks Alex, you might be right about that. I'll use that technique to monitor it further.

cytoxin · #8 12-23-2007, 10:11 AM

I USE LIQUID TEFLON ON FITTINGS THAT ARE TAPPERED IN OIL APPS.

pauldan181 · #9 12-23-2007, 10:43 AM

I used medium weight Titeseal on all fuel, oil, and brake NPT fittings on my plane. I also amd fighting a few tiny oil leaks on my Aerosport O-360 but nothing with assembled with Titeseal has ever leaked. Aircraft Spruce has it as well as some auto part stores.

Paul Danclovic
Carver MN / Albuquerque NM
RV-8A at the paint shop

Mike S · #10 12-23-2007, 12:06 PM

Paul, in your first photo, there appears to be a crack in the casting where the cylinder base stud is.

Perhaps it is just something in the photo------sure hope so, as the crankcase is a bit expensive------but if that is indeed a crack, that may be the source of your oil leak.

Or, am I just seeing things????