Greetings, all,

I thought I blew my turbos and have been pricing the job out. I spoke to a gentleman at a respected Audi shop and he had some different opinions. I'm completely new to forced induction- I've been my own mechanic for years but I'd appreciate some help with the new concepts.

The car is a 2002 S4 Avant with 94,000 miles. Timing belt was recently replaced.

Symptoms:

-Car blows a puff of oil smoke on startup and on overrun from the tailpipe. There is some smoke under the hood coming from both sides of the motor. The turbos look clean. I see an oil fitting on the top of each turbo- each side is clean. Oil is German Castrol Syntec 0W-30.

-Car has full power in first gear to redline 100% of the time. In second gear, it's a crapshoot what will happen after about 4000 RPM- sometimes the power continues, but more frequently it drops off dramatically.

The gentleman I spoke to doesn't think the turbos are fried. He believes there's definitely a problem, however. He wants me to start by checking the breather to make sure it isn't clogged. Could a clogged breather be the source of my smoke problems, both under the hood and out the tailpipe?

Does anybody have any suggestions about either symptom? As odd as it sounds, I'm more concerned about the oil burning than I am about the power (at least until the burning problem is solved).

Thanks in advance,
Rob Theriaque

 

More info... I started checking the intake tract. The entire thing is covered in oil.

I started by pulling the throttle body boot. Oil. I pulled off the hose between the airbox and the y-pipe. Oil. Looks like the oil is coming from the breather. Any ideas why it could be so much? Any suggestions on what to do?

Thanks!

 

I blew compressed air through several breather openings (only one open at a time): each bank, the valve directly linked to the Y-pipe, and the orifice in the intake boot between the airbox and Y-pipe. The only one that gave me any airflow through the oil filler cap was on the left (facing the engine) bank.

It looks like the oil is entering the intake tract through the plastic intake boot between the airbox and Y-pipe and/or from the valve attached to the Y-pipe.

I've buttoned the car back up as I've taken it as far as my naturally-aspirated and 70's era knowledge will. Any help is greatly appreciated. I doubt a catch can is the answer!

 

The crank case ventilation is routed into the y-pipe so some oil in the intake tract is normal.

Is there oil on the sparkplugs? oil in the coolant? coolant in the oil?

If so than its a headgasket, it would be puffing lots of smoke, causing misfires so you wouldnt have power. Is your CEL on?

Usually with blown turbos there will be lots of smoke from the exhaust and a loud dentist drill sound. These cars are known to have oil leaks though from a bunch of places...

What did the person at the audi shop say?

 

Thank you for your reply. I appreciate your time.

I haven't had the car to a shop yet- I've been nervous to drive it.

There's far too much oil in the intake tract to be normal. I had the intake apart two months ago to replace the throttlebody boot- there was a film then, which I took as normal. I'm seeing pooling now.

The plugs are nice and clean. I changed the oil a week ago and it was clean. The coolant is also fresh. I've seen no evidence of a head gasket issue, thankfully. I played that game recently with another vehicle- I'm unfortunately well versed. Grr...

I have no check-engine light illuminated.

I've been exploring the breather possibility. I don't see any evidence of a check valve that would prevent compressed air blown from the left bank's breather from escaping via the oil filler.

I haven't seen an Audi/VW-specific site that stocks the breather hose. I've seen a few online wholesalers, but I haven't had good experiences with general parts sellers. The only Audi parts sites I have tagged are the Audi Parts Superstore and RapidParts. Any others I should be aware of?

 

how much oil did you put in? i hope you didnt overfill

 

Thanks, but no, I didn't overfill.