Severe Oil Leak Question

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Gene Wesolaski
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Severe Oil Leak Question

#1 Post by Gene Wesolaski »

Greetings,

I searched the forum, but I thought I would post my question anyway.

I replaced both main seals (flywheel and pulley) to rectify an oil leak I have on the flywheel side of my 356A.
Not wanting to do it again, I was very careful to do the job correctly, or so I thought. After the repair
the oil leak is still there.

The attached pic is after my first 15-minute test drive, with car off, sitting in my garage for 5 minutes
It looks like the main seal is leaking to me.

Question. Before I pull the motor again any words of wisdom would be appreciated. If it's not the main seal,
what could it be and how do I find the problem? Could this be caused by an oil cooler or oil pressure relief valve
issue? When I replaced the seal I did not use any silicon between the metal ring of the seal and the case,
should I have?

Thanks in Advance,
Gene
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Martin Benade
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Re: Severe Oil Leak Question

#2 Post by Martin Benade »

Look on the top of the case, ahead of the distributor. Chances are an oil cooler leak would show up there before running down to the bottom.
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Al Zim
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Re: Severe Oil Leak Question

#3 Post by Al Zim »

Check the end play on the crank. Call me with your results and I will diagnose for you 817-235-4415 Zim The leak is at the front (fywheel end of the engine, the oil is black indicating used oil Oil cooler leaks come down from between cylinders 3 and 4. Rear oil seal (oil pump) drip from the sheet metal to the rear down the crack between the two rear sheet metal pieces. You might want to give Vic Skirmants a call on this his phone number is listed in the latest registry.
Last edited by Al Zim on Fri Jan 20, 2023 1:17 pm, edited 1 time in total.
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Wes Bender
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Re: Severe Oil Leak Question

#4 Post by Wes Bender »

I would have used a very light coating of Aviation Permatex (the non-hardening kind) on the case/seal surface when installing. If the oil is not visible at the top of the case, could the leak be coming from the cam plug?
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Re: Severe Oil Leak Question

#5 Post by Chuck Allard »

When you replaced the flywheel seal, did you use a single or double lip replacement seal? If a double, that is most likely the problem. If a single (always recommended) perhaps there is a groove worn on the flywheel seal area where the lip of the seal mates. When you pull the flywheel again, look for a groove worn in the flywheel and if there is one, purchase a speed-i-sleeve from Stoddard and install it on the flywheel to solve you problem.

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David Aronson
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Re: Severe Oil Leak Question

#6 Post by David Aronson »

I had the same problem years ago. I replaced the front seal several times and ruled out other sources as recommended by others. The engine was replaced (see why later). I sent the parts (30 years later) to Walt at CE. The case had a crack through the oil journal on the front of the engine, above the crankshaft . It was repaired against long odds. Keep at it. Next time you remove the flywheel, inspect the front of the engine very closely. BTW, I ran the engine with a dripping oil leak for a few years before the crank broke. That is why it was replaced. Nice to have a spare.
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John Brooks
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Re: Severe Oil Leak Question

#7 Post by John Brooks »

I would thoroughly clean the entire exterior of the case with a de-greaser, then start it let it run for 5 minutes, shut it down and get under it and look for where the oil stains are coming from. There is only a few places it can leak from. The flywheel seal and pulley seal are pretty easy to detect. push-rod tubes, Temp and pressure senders, oil filter lines are all easy also. the oil cooler and cracks are a little harder, But start with a clean case and look for oil stains. De-grease, then spray brake cleaner on the case so it is bright makes it easy. A good strong light source helps.
Last edited by John Brooks on Thu Jan 19, 2023 11:34 pm, edited 1 time in total.
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Chuck Allard
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Re: Severe Oil Leak Question

#8 Post by Chuck Allard »

Plus one on what John said above. I sometimes put some florescent dye in the oil and run the engine for a few minutes, shut it off and then inspect with a black light source. Very revealing of the leak source.

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Greg Bryan
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Re: Severe Oil Leak Question

#9 Post by Greg Bryan »

Did you also replace the soft iron gasket that goes between the crank end and the flywheel? It will leak without it. Al Z is correct about checking the end float of the crank/flywheel - 5-7 thousandths of an inch - while it may not cause a leak per se, it's an indicator of engine wear or poor setup if it's too much.
I've seen them leak between the case haves, although it's rare.
Wolfburg West has the correct seal - they sell it for the 36hp VW but it's the same and it fits properly.
All the advice I see here is good too.
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Dick Weiss
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Re: Severe Oil Leak Question

#10 Post by Dick Weiss »

Gene,

Have you cleaned off the engine's bottom and re-run the engines for a few minutes?
Possibly the sump plate is warped (from over the years) when R & R-ing the nuts & washers.
If you replaced the sump plate w/the aftermarket aluminum plate, it won't leak due to a
machined thickness.
If the oil is leaking from the notch in the bell housing's flange which would be from the F/wheel
seal--it's engine oil; Trans. oil is much thicker to leak from the input shaft's seal and your leak
most likely, is much quicker. (w/o a smell)

As others replied, if there's oil on the top surface of the case from under the upper #4 air guide,
(attached to the F/shroud), the oil cooler may be leaking, or the cooler's pad may be cracked!
It can be seen w/the spark plug terminal removed and using a small mirror and flashlight to see
if oil is leaking after a few minute run. That's the worst!!!

Finally, if you used a double-lip F/wheel seal, the extra lip must be removed, use a "single-lipper."

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Greg Bryan
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Re: Severe Oil Leak Question

#11 Post by Greg Bryan »

Any update on what you found?
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Vic Skirmants
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Re: Severe Oil Leak Question

#12 Post by Vic Skirmants »

I had a race engine that had a loose plug at the end of the main oil galley. That's covered by the flywheel, so you have to remove the flywheel to see it.

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