huwla

After 10 years and 119k miles of blissful motoring I've just been told that my engine may be a total loss. About a month ago the check engine light came on. Like any good decade-long member of AW/QW, I hooked up my VAG-COM only to discover the following:

16684 - Random/Multiple Cylinder Misfire Detected
16687 - Cylinder 3: Misfire Detected

Hmmm, what could this be? Well, the local shop in Seattle has concluded that Cylinder 3 is probably damaged due to a leaky head gasket. They removed the spark plug and performed a compressed air test. Unfortunately, the air came out the oil filter which means the cylinder and/or seals may be damaged. The hypothesis is that the head gasket allowed coolant to get into the combustion chamber, washing away the oil. If this is true then the walls of the cylinder may be scratched.

The shop gave me these options:

1) Punt - Sell the car now. This was their #1 recommendation.
2) Risk the Cost of an Engine Pull - Pay the money ($3000) to have the engine pulled and inspected. If I'm lucky the cylinder is fine. However, if I'm unlucky, I may have payed money only to discover the engine is a loss.
3) Get a Used Engine - I'm not even sure if a reliable used engine is possible to source for a reasonable price.
4) Just Drive it Til it Dies - The check engine light is the only telltale sign. The car currently drives just fine but I understand the risk.

Any advice from the forum on this dilemma? I really want to keep the car. BTW, this car is completely stock.

Huw

Peter Badore

Try to find a good used engine of the correct transmssion application.
Find an independent shop that works on Audis. Do not try to repair the existing engine if the diagnosis given to you is correct (second opinion needed?).

Preatorian

Well I just finished rebuilding my S4 motor with similar codes. The difference was my turbos had exploded(Which was how I bought the car). Long story short it sent pieces through the motor scoring the walls and bending valves. Cost was about 1500 for parts and machine shop service not including I replaced all sorts of other worn parts and all fluids while I was in there. That was my costs doing it all myself. paying someone you'll have to add a ton for labor. It's a long process to remove the motor. In the end though I have a car that I know is 100%. no questioning the new/used motor.

Preatorian

oh and one other thing you can try first is to run a bottle of risoline in the oil. it'll help clean out carbon deposits in the valve train and if its just sticky valves or sticky piston rings might solve your problem. The bent valve in my head caused the same problem you have. (Blowby in crankcase felt at oil cap and low compression giving misfires) Sticky vlaves and piston rings can give you the same scenario.

ur20v

So have you been seeing clouds of puffy white smoke behind you everywhere you drive? Is your oil a pinkish-grey-brown milkshake? Are you refilling your coolant resevoir every other day? If your answer to these questions is no, it's time to get a new shop.

Swap the coil from cylinder 3 to cylinder 1, 4, or 6. See if the misfire stays put or travels with the coil. If the misfire changes to another cylinder, coil is your issue. If the misfire doesn't change, spend $6-12 on new spark plugs, gap them and swap out the old ones. Report back with the results - if the misfire remains we still have more options.

I can't tell you how many times I have heard people getting a terminal diagnosis from their 'trusted family mechanic' only to have it be something far less severe. Hell, I once had 3 specific misfire codes, a random misfire code and a cam adjuster code - my friend, the factory trained Audi master tech, took one look at the vagcom scan results and said "you're screwed, your t-belt jumped teeth, your timing is off". And you know what it was? The screw-on electrode on top of all 3 spark plugs in bank one were loose. That was it. I set them with a bit of Loctite and the codes never returned.

huwla

$1500. How did you pull that off? Turbos alone would be close to that.

huwla

Took it to a different shop and pulled the engine. Exhaust valve is shot. Sourced a rebuilt head.