S6Avant

I was hoping to get suggestions on a 2002 S6 Avant that I have had for about a year now. I bought it from a dealer with just under 100k miles on it. Had a great history of service records and seemed to be cared for.

The issues started with I put the car through an automated CAR WASH that caused the car to stall, put out white smoke, and seemed to tweak the electrical system by having the engine light flash on and off.

Since then, I have gotten multiple opinions on what has happened. It seems the logical explanation was that the car had water shot up through the intake (maybe from an under carriege spray?)and caused serious damage to the engine.

The car is now reading low-compression in a cylinder #1 and I am told that it needs major engine work, or an engine replacement.

Is it really possible for a car wash to take down one of these cars? I am at a loss for what has happened.

Any suggestions or interest in the car is welcomed. Thanks.

socalclimber

White smoke = burning water (or coolant). Was white smoke sweet smelling, indicating coolant vaporizing?

Either water got pulled in thru intake, or something let go (blown head gasket?) that is a purely a coincidence.

If water got pulled in thru intake, air filter would have been saturated, but it seems hard to imagine unless a stream of water was pointed directly into air intake near front grill.

Was air filter drenched in water? If a significant amount of water came into combustion chamber, pistons would hydro-lock when they hit the incompressible fluid, possibly causing damage.

Did you keep trying to start/run engine after this happened?

Sounds like you have car at mechanic already. Do tell more of the details.

OOOOya

Mine has been through a drive through car wash many times over my 5 years of ownership.
If the cowl drains are blocked (common), maybe the ECU got wet...might explain the twitchy electrical, but not the smoke.

The primary air intake is in the front grille, I can't imagine enough water spray to fill up the airbox...

S6Avant

Once the car wash incident occured, it did restart but with some difficulty. I limped the car back to my house which was only about 1.5 miles from the wash.

So far it has been to two different mechanics and an Audi dealer. At the first, they replaced the valve cover gasket and put all new spark plugs in. This was the first time I heard about the potential for a lot of damage, but none of the mechanics could believe it came all from a car wash. There was also a tapping noise that they claimed was a timing chain.

The dealer was the next stop who brought up the compression issues.He said that cylinder #1 was firing at around 90psi and that the engine was showing wear.

He said that we were looking at potentially an engine replacement to the tune of 9k to 10k dollars.

At this point, the car will start and run but I have been cautious not to drive it.

Has there been any horror stories like this regarding a car wash or water exposure? I love this car and find it odd that a car of this caliber would succumb to this.

Huskerbob

You should have a plastic cover UNDER the engine, if that makes sense, which would prevent water from blasting up to the engine.

Water cannot get through the air inlet/filter system unless the system is somehow compromised. Too many bends and turns for water to get sucked in that way unless your air filter is missing or totally drenched so that water is being sucked into the intake. That's hard to picture.

If water intruded through your fresh air intake, at the passenger side lower windshield cowling, it may have run down onto part of the computer that is under the passenger side floor mat. Not sure if you have electronics at that location but I did on an '01 A6 Avant.

Check the passenger side carpeting and pull it away from the firewall if you can and see if it's all wet under there. You'll be able to smell the mildew as well.

What codes are you throwing?

Don't go all "new engine or engine overhaul" yet until you diagnose the problem.

Does the car run? Have your mechanic pull the codes and then post the results.

mithrilG60

The TCU sits under the passenger carpet, the ECU sits in the rain tray on the drivers side in a very water sealed box. If this was an issue with water leaking in the cabin and causing problems he'd be seeing transmission faults not a (potentially) blown engine.

ddillenger

Sounds like the low compression is unrelated. Any codes?