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Is a root cause known for rear main seal leak/failure?
Bad seal component?
bad crankshaft machining or tolerance?
damaged seal during factory assembly process?
failed oil/vapor separator causing crankcase overpressure?
something else?
I had the same leak and Audi found out it was the oils filter housing, was a $1200 job but I had extended warranty
That doesn't seem like the same leak then, the oil filter housing is on the front of the S4/S5 3.0 engine, this leak was definitely coming from between the engine and transmission.
I have the same leak. Took car into an indie shop last week to fix the oil cooler gasket and oil filter housing for the leaks up top in the valley and was hoping that was the cause of the bellhousing drip but after servicing, cleaning up and putting some miles on it they confirmed that it's still leaking from bottom. Likely a timing cover seal issue they said it would be engine out, $7.5k.
And with that bit of knowledge gentlemen, its time I hang up this little experiment called Audi performance car ownership and move on into the sunset.
The engine does not need to be taken out, only the transmission. It can be done for 12-20hrs of book time depending on the shop/dealer. If doing the RMS I'd also recommend having the timing chains inspected and cover resealed too as it will then be easily accessible and is another possible cause of the leak in that area.
Update on my problem. Took it to a place and they said it's most likely timing chain cover, 4k quote. Flashed my car back to stock and finally took it to audi for my 50k service and brought up the leak. Audi found it to be the transmission cooler line that runs right below the bell housing. There's a small leak that sprays transmission oil and can spray up to the bell housing making it look like it's leaking from the RMS. If you have oil on your line right below the bell housing and it looks like it was sprayed everywhere, that's probably your culprit. My only concern is that I was driving with low transmission fluid for 10-15k but doesn't seem to be too bad.
Audi is covering the replacement of the transmission coolant hose return line and refill of transmission fluid.
2018 S5 Sportback Sedan 47,000
I'm starting to see a small rear main seal leak. Did you guys originally see a small leak like this that eventually expanded?
CPO warranty till 60k
Service advisor said its a small leak or "residual oil"; they put in dye in the engine oil to further diagnose it.
Seems like they are trying to get out of further diagnostics till my CPO expires 7.2024
02-18-2023, 08:37 AM
