Various oil leaks - some advice needed

A6 All/ S6 All
#1

I’m the proud owner of a 2006 V10 S6. I’ve had the car for around 2 months and I got it for a good price. I think I’ve found out why now. After getting the car I took her for a complimentary health check with Audi. They found an oil leak that wasn’t apparent when looking at the underside of the car. I took it to an Audi specialist who couldn’t find the source of it. He left the engine running for an hour and it didn’t drip. He said ‘next time you bring it we’ll have a proper look.’ I’d have hoped he’d had a proper look the first time really.

I then took it to another garage who pretty much straight away identified the leak as being the front crankshaft seal, and likely the rear seal too. It is also probably leaking from the bottom pan (I forget it’s actual name). The quotes for the work are very realistic. I know there’s a lot involved; removing the transmission, removing the front bumper etc. Could be worse though!

I’m a bit of a car DIY’er, but the V10 and Audi in general are beyond me. I still like to understand what’s going on. After reading through this forum I’m suspecting that the crankcase breather system may not be working leading to seal fails on the front and the back. I don’t want to replace the seals without identifying why they’re leaking. I’m hoping if I’m right I should be able to replace the breather oil separator and check for blockages and the seals won’t fail again.

I’d be interested to hear if I’m on the right lines or if there’s something else I should be thinking about. I don’t have any misfires, the car runs and pulls smooth, and the oil level doesn’t move much (probably because he overfilled it so much before he sold it to me knowing it had a leak!). She’s a fast little bugger too with no apparent flat spots so I think the engine is fine.

Once I’ve sorted the leaks I’ll be taking the car for a carbon clean and tune. Then I’ll be looking forward to trouble free motoring…

#2

Welcome to AR.

The V10 is shaping to be a great new platform and whats good for the V10 guys is that the V10 is very close to the V8 S4. It seems lots of the same issues that can show up on the S4 are there on the S6. Other then the carbon issue the V8 S4 didnt have that against it.

As for the oil leaks. The usual suspects are the valve covers first. The valve cover gaskets almost always leak and start the first line of issues. The crank seal on the front and back can be an issue but usually not as major as the valve cover gaskets. The formula that works best for the S4 is. Replace the VC gaskets install intake spacers (from JHM the remove lots of under hood temps) and inspect and or replace your PCV and oil separator.

The good part is you can install the spacers and VC gaskets when your going the carbon clean and carbon cleaning is a big plus. If you let the carbon go too long on the V10 it can take out injectors and then 02 sensors. This on top of giving you a bad misfire on cold start.

One thing to look at is your intake manifold. When you pull it off check the part number that should be on the underside. The v10 motors had big issues with failing intake manifolds. So checking that out would be a good idea as well.

Welcome. This is a much more car and excitement based forum. Lots of great technical guys here to help. So dont be afraid to ask any questions you might have

#3

Thanks for the reply. I’ll get him to check the valve covers when he’s stripping the front end off.

I need to try stage the repairs best I can; the carbon clean costs £1000 near me. There’s a company which is about 4 hours away that charge £250 for the clean, and for another £150 they’ll remap the ECU. So ideally I need to get the oil leaks fixed near me and then book it in for the carbon clean separately.

So it’ll be worthwhile to change the valve covers and possibly PCV when I have the carbon clean done. I’ll look into the intake spacers. Good to know; thanks! I may get the oil separator changed now as I don’t want the oil leaks to be repaired and then the faulty crankcase breather system cause it to leak again. It’s a bit of a gamble.

#4

Does anyone know if when changing the front crankshaft seal you need a special pin to hold the crank in place and retain the timing? I don’t know if it’s a floating crank or not.

#5

I’m not sure about your other questions, someone else here will be more qualified to answer those than me… but I will say, that when you “check” your valve cover seals, you might as well just replace them for $50 each. You can’t really reuse your aging gaskets after you’ve popped your valve covers loose.

Oil leaks are really a pretty minor problem. Don’t stress. Even on a rare V10 like this one, replacing all your gaskets doesn’t cost your life savings.

#6

There is a tool to stop the crank from moving but I dont think you need it to change the seal. I think there is a diy here in the tech section on how to do the front seal. But its for a 3.0 still that shouldnt be too much different then what your doing.

The carbon clean for 250. Make sure they are actually taking off the intake manifold and cleaning the valves and not just spraying something into the intake or putting some additive in the tank. I would also wait a while after getting the CC done to try and get a tune. Sometimes carbon cleans can bring out other issues or on reassembly issues can linger.

#7

Great stuff. My mechanic doesn’t have all the Audi tools to do everything. He wouldn’t want to buy the specific tool just for my car as he won’t see likely another V10 again. Sure it will be fine. I found a DIY relating to the 4.2 V8 which should be essentially the same though and he didn’t use any specialist tools.

In regards to the carbon clean, the guy who is doing it for £250 said they use this method:

“As to the Audi S6 we use this product http://www.forteuk.co.uk/product-detail/20/Petrol-… for the carbon cleaning and we choose to use this visually to maximise results. IE we strip the manifold off and manually use the product to guarantee all the carbon deposits are removed as well as vacuuming the residue from behind the valves so as not to contaminate the internals of the engine. We use this method to minimise any wear issues and to maximise the effectiveness of the job done.”

Does this sound like he’s doing a proper job?

#8

He also talks about removing the flaps prior to the remap, which after reading this forum doesn’t seem beneficial at all. I’m not keen on this part.

I’m starting to lean towards getting the following done:

  • remove and inspect manifold and hope it’s not faulty (£2000 replacement ::))
  • remove valve covers and replace seals with JHM spacer ones
  • replace oil separator and pcv from crankcase breather system
  • carbon clean
  • sort out the crankshaft oil leaks
#9

The list you put up is the best list for a happy well running car.
Checking the intake is a great idea. It is a big help in getting more hp out of the car. Having a healthy intake is a big must
The spacers help drop the under hood temps drmatically and keep the intake charge nice and cool for hp and keeping that hp
The PCV is always something to look at to keep the motor healthy
Carbon clean is another must. Its just good all around
Seals from the oil seals to the intake gaskets. this helps keep the burning of oil and small vac leaks at bay.

Your right to worry about the idea on removing the flap. Thats just not a good idea. It is just a hack way to go about working on your car even if the intake flap system is broken. Its still better to lock the intake on the long runner.
And as I said. I would not do the remap for a while after the work. Its just smart not only that but the same guy that wants to remove the thing from your intake that helps the motor make big power wants to remap the motor. I would pass.

#10

I’m looking to get the work done by someone more local now who doesn’t offer remaps so won’t be getting that done. Can I ask why it’s not a good idea though? Is this in case the repairs cause another issue, ie vac leak or carbon damaging the cats?

I’m messaged jhm; hoping they have a UK supplier.

#11

JHM are in the process of manufacturing the spacer gasket so it’s not going to be ready for me unfortunately.

I took the car to the mechanic at the weekend. When the car was idling he lifted the oil cap off and the car started sucking air in and nearly stalled. He’s now checked the oil separator and it is faulty so that’s being replaced.

After stripping off the front end and intake manifold off it looks like the oil is leaking from the base of the oil filter housing, just like SgtMontys. He’ll replace the crankcase seal while the front end is off as that appears to have been leaking too. I’m guessing the car spewed oil from every orifice to get rid of the pressure because of the faults with the breather system.

The carbon build up is a right mess; I’ve not seen the car yet but the mechanic is amazed that any air can pass though some of the valves. I’ll take some pictures when I’m with the car tomorrow. I’m going to go and get my hands dirty with the clean up. I’m looking forward to seeing how the car goes without all of that gunk in there.

I might be thanking this forum a little prematurely but if I’d not read up on here first and listened to some of the advice I would have made some poor choices regarding this repair. Thanks in advance!!!

#12

I know someone local who just got a set of spacers for his V10 PM jake@jhm on here he can get them out I would think.

All of the V10s that I have seen have that oil leak from the base of the oil filter to block connection. Seems those seals go bad somehow. From what I have seen on the v8 cars its heat so it might not be a bad idea to doubble check with JHM on the intake spacers.

#13

A few reasons for this.

1 after a carbon clean you can have little missfire issues and vac leaks can pop up. Having the car running as OEM as possible. Also the big deal is that carbon cleans and maintance work helps the car run better and perform better. This was a big deal with the rs4 guys. They would get carbon cleans and tunes at the same time. The scam was that some guys were picking up 20whp on a carbon clean and some of the forign tuners would try to have carbon cleans and tune deals as they knew the tune alone would make no difference but the carbon clean would make a big difference. They would piggie back the gain in performance and smooth acceleration with the carbon clean and try to say it was from the tune. When some guys had to go back to stock ECU to go to the dealer they would actually see a faster better running car. We want to make sure to not let that happen to the V10 guys.

#14

I had a suspicious oil leak from the front of the engine… except it was actually from where the oil filter housing meets the engine block. What happens is the valley fills up with oil and when you stop or park on a decline it drains out the front of the block.

If you are doing the carbon clean, check this anyhow. It’s an o-ring seal that was broken on my S6 and was $3.00 from the dealer. I suggest you change it while the intake is off.

I thought it was my crank seal or something like that… but when I investigated it was from below the oil pressure sensor but above the crank. The two drains are near that area, maybe a few inches above the crank pulley.

Wish I still had the part number, but it’s the o-ring for the oil filter housing between that and the block. Looks like a figure 8.

Hope that helps.

#15

Wish I knew how to edit! Looks like I should have read the whole thread first!

But now it’s looking like a more common fault… so add that to the carbon clean DIY, change the o-ring for the oil filter housing.

#16

^^ keep posting. At 150 you’ll be able to edit.

#17

We should make a thread on just that. That is a common issues on all the V10 motors