Oil leak between engine and gearbox

[controlz]

Hey,

I'm about the purchase a November 2008 S3 that's in almost perfect condition (1 owner and 30k miles). I've had a vehicle inspection on it by Dekra, and the inspector said there is an oil leak between the engine and gearbox, which is probably the rear main oil seal. This is the only fault with the car.

Is this quite major and an essential thing to get repaired, and if so is it likely to be expensive?

Thanks

 

[jaydav2306]

Is it engine oil or transmission oil did they say? Could be anything, had this on my TT and it salve cylinder leaking onto the gear box I think, ended up having new slave/master and a clutch

 

[controlz]

Is it engine oil or transmission oil did they say? Could be anything, had this on my TT and it salve cylinder leaking onto the gear box I think, ended up having new slave/master and a clutch

said it was a small amount of engine oil, so probably the rear main oil seal.

 

[Rom]

Requires removal of box and flywheel to replace. Once they are out, it's not a hard job.

It will need doing. But could could for years and never get worse.
Main issues will be oil onto clutch and low oil level. But there is no way of knowing what will happen, if it's just a seep and will be fine, it will dump all the oil next week.

If you can negotiate the price to allow labour for a clutch, then could still be worth it.

 

[controlz]

Requires removal of box and flywheel to replace. Once they are out, it's not a hard job.

It will need doing. But could could for years and never get worse.
Main issues will be oil onto clutch and low oil level. But there is no way of knowing what will happen, if it's just a seep and will be fine, it will dump all the oil next week.

If you can negotiate the price to allow labour for a clutch, then could still be worth it.

Thanks for this comprehensive answer. Since you mentioned flywheel, I know it had a flywheel replaced under warranty in 2011, perhaps something around this time caused the RMS to start leaking too.. (not sure why Audi didn't pick up on it!)

 

[Rom]

Sorry, just realised some mistakes in it. Damn phone !

A new flywheel shouldnt have mattered. The seal sits behind the flywheel, but theres no real way you could damage the seal when doing a flywheel. Not by accident at least.
The crankshaft is what the flywheel bolts to, it protrudes through the engine block just slightly, with usually 8-10 bolt holes. The rear main seal is what seals the crankshaft to the engine block. Its the same design as a driveshaft seal, camshaft seal etc. Has a spring inside to keep its shape and fit.

The only reason it would fail is just a faulty seal really. Nothing can really contact it, or do anything that would damage it in normal operation.
Excess oil pressure can blow them, but it would be a severe leak.

Without seeing it, its hard to offer much more advice. Its not impossible its leaking from above the gearbox, and running down the block, giving the impressions its coming from the rear main. Like wise, either side, and running down the bellhousing / mating faces.
But you would like to think they would have spotted this on the inspection.

Thats if its 100% engine oil. And not gear oil, dirty clutch fluid (from dirt under car, not dirty fluid itself) etc....

 

[controlz]

Sorry, just realised some mistakes in it. Damn phone !

A new flywheel shouldnt have mattered. The seal sits behind the flywheel, but theres no real way you could damage the seal when doing a flywheel. Not by accident at least.
The crankshaft is what the flywheel bolts to, it protrudes through the engine block just slightly, with usually 8-10 bolt holes. The rear main seal is what seals the crankshaft to the engine block. Its the same design as a driveshaft seal, camshaft seal etc. Has a spring inside to keep its shape and fit.

The only reason it would fail is just a faulty seal really. Nothing can really contact it, or do anything that would damage it in normal operation.
Excess oil pressure can blow them, but it would be a severe leak.

Without seeing it, its hard to offer much more advice. Its not impossible its leaking from above the gearbox, and running down the block, giving the impressions its coming from the rear main. Like wise, either side, and running down the bellhousing / mating faces.
But you would like to think they would have spotted this on the inspection.

Thats if its 100% engine oil. And not gear oil, dirty clutch fluid (from dirt under car, not dirty fluid itself) etc....

Thanks Rom,

The engineer said it was only a minor leak of engine oil, so I can't imagine it's something major! :S

 

[controlz]

Would you consider not buying a car because of it, even if everything else is immaculate according to engineer?

 

[Rom]

Me ?

No...but im a highly skilled tech lol. I rebuild engines and gearboxes regularly, built many project cars etc. I have a different view on buying cars. Id buy a car that needed an engine rebuild for the right price

If i was a average joe, id probably try and knock it down a bit with the engineers eveidence. And maybe see it as a blessing to get uprated clutch / flywheel, seeing as you 'need' to take the box out for the oil leak

In all honesty, i doubt its going to cause any problems. I see leaking rear mains a fair bit, often the same cars year after year, very few people chose to replace them if its just reported on routine servicing.
If its reported on a clutch, almost everyone has them, as its no extra labour, and the seal is £30 ish.
Absolute worst case scenario, it suddenly gives, dumps your engine oil, spins a shell or similar. Unsure if you have a level warning. But low pressure light will come on, providing you stop right away, no real damage should be done. Though low pressure lights are always a bit too low for my liking.
The chance of that is very slim, and as i said, thats as bad as it gets (bar destroying the engine, but again, thats extrememly unlikely)

If i saw my rear main leaking tom, i wouldnt rush to fix it. It would wait unitl it needed a clutch, or it got worse, to the point im seeing oil level suffer, stain on drive etc. Im not trying to put you off with doom and gloom, just outlining the possibilties.

 

[controlz]

Rom, your reply is great, thanks so much.

As a car that has been serviced every single year for the past 5 years at Audi, can you think of why this would be leaking? Surprised it didn't show up in the service beginning of last year!

 

[RobinA3]

I'd walk away - there are a many other S3's for sale so I wouldn't risk it - the oil leak won't get better - it will only get worse. Yes it may remain the same for a whole how on the other side of the coin it could get worse very quickly.

To change the seal I would expect a independent Audi / VW specialist to charge about £300 - £400 in labour alone if not a little bit more.

 

[Rom]

Its possible its only started leaking since the last service. Or that the tech didnt deem it worth noting. There is an obligation to report faults on cars, but you also dont want to be seen as trying to fleece customers. He may have thought re check it next year etc, who knows.

Robin is right, it will never get better, only stay the same or get worse. I really dont know much on the S3 market, so ive no idea how easy it would be to find anotherm, or if you have room to haggle the price.
If its from a dealer, maybe they would repair it, or offer a warranty, which then would cover it after its bought. That way they dont pay the cost of the repair, the warranty company does.

 

[controlz]

The car is immaculate for its age, with 1-owner and 30k miles in 5 years so it's going to be hard for me to find something similar. I knocked the price down by another £250 which I think is acceptable.

As the leak is very minor, I think I'll monitor the floor under my car for a few weeks and see how much it leaks. If it's literally only tiny drips ever so often, would you recommend not spending the money on a repair yet?

 

[Rom]

Id spray a load of brake cleaner on the top of the bellhousing, so it runs down and wases any oil out. Assuming you cant get under neath to do it.

Id then monitor it like you say. I cant say never fix it. Its not my call. I can say if it was me, and it wasnt leaking much, and it wasnt making the clutch slip, id leave it until a time it did leak more, or make the clutch slip, or when i did the clutch for a stage 2 etc.

If its garaged, place something under it, paper, etc, makes it easier to see. If its on a drive, you can use a peice of wood, or similar, so it cant blow away, and if needed, staple paper to it. Shouldnt get wet when cars over it. So just slip it under at night etc.

So youve bought it ? £250 wont cover the repair, but it will certainly cover some of it. Which fingers crossed you wont need to do until a clutch is needed anyway. A lot of people would never have known its even there, and just bought it.

 

[controlz]

Well, drove the car hard and been sitting in the driveway for 12 hours and not a drop of oil underneath. Guessing it's being deposited onto the sump guard...? My assumption is the leak is incredibly minor with just the odd drip!