I'm stumped about a problem with my 1999 A6 2.8, ~55k miles.

Car has run very well, no problems at all. Until...

In mid-February, the Chicagoland area had a serious cold spell, with temps down to -20 and below. My A6 had to sit outside during that period, and understandably wouldn't start one morning. Took the battery inside, and waited until the temperature moderated to at least above freezing. Replaced the battery, car would crank fine but seemingly no spark, barely even a mild cough or two during 30 seconds of cranking. Not to worry, have another car to drive, so just waited for temperatures to rise, and tried starting periodically. No improvement.

Had the car towed in for service. Got a call back saying there is a serious compression problem with the engine, one cylinder within normal range (125psi), other 5 cylinders in the 60-80 range. Was told this would indicate a "low engine problem" and "could be as much as $10,000". I was both very shocked and very skeptical and told the dealership I needed to consider. Got a call back a few hours later, told that upon further investigation "the valves are stuck (maybe he said sticking) open" and that a "cold start package" would help and that would be about $3,000. Told them to fax me something showing the repairs involved. Nothing on the list (water pump, injectors, coolant temp sensor, spark plugs, decarbon) would have any conceivable effect on compression. Separate from the "cold start pack" on the suggested repairs was a timing belt, water pump, and serpentine belt replacement, of which I'd be tempted to believe the timing belt might be an actual cause of the problem.

That kind of a compression issue, I'm told, should cause very noticeable performance problems. Car had NO problems prior to the cold snap.

After asking around, only things I've heard which are plausible are:

1) Timing belt broken or skipped a few teeth (cold weather effect?)
2) Head cracked due to extreme cold (seems very long shot, although I did hear from someone knowledgeable who experienced this on another make/model)
3) spark pack (not sure what this is)

Advice, anyone?

(I'm looking around for an independent mechanic at this point)

 

Have a leak down test done. This just doesn't make any sense to me. The valve should never be "stuck" it has a spring, & a piston to know it back up. If it's stuck close, you would break the cam.

The TB could be the problem, but cold alone should not change the timing, unless the tensioner is stuck. Doing a Vag-com log should tell you. The cam sensors will also be off, & should throw a code. Yes, it can be a coil pack, but they will NOT change compression.

You might need to pull the heads off & see if the head is cracked, or if the cold caused ice to form in the coolant, & blew a gasket.

I would find a better shop! It look like they just want to sell you parts & labor, & not fix the cause.

 

i belive the v6's use a timing chain first off and those really nvr advance although its possible. Id deff do a wet compression test. It could be your rings, head gaskets for your heads could be a problem. thing that has me convinced its timing is b/c your gettiing poor compression in all but one cylinder. more and likly means valves are stuck open when they should be closed. and btw it wouldnt break a cam if the valves were stuck closed, it would actually send them through the piston first or bend them in the cylinder. Take it to another shop or start tearin it down urself. n save alot of money.

 

B5gen, I am sorry for name calling, & taking the post out of topic. It was brought to my attention by Dave, what you were talking about.

There is a TB on all of them. However, the cams are chain driven off the TB. This is a classic case of not being descriptive & people taking things out of context.

 

Where are you from b5gen?

 

There is a common problem with v6's , well ive seen it bunch of times.
when its really cold out especially... The eng gets flooded and all the oil is cleaned out of the cylinders and it looses compression.
The fix - removed all the spark plugs and spray a couple sprays of oil into each one.
Then crank like you've never crank before.
I would get a new ECT sensor and some new plugs.
The Dealer should Know this............................................

 

A leakdown test will tell all, then you'll know if it's ring or valve related. Andas strange as vaudi's post sounds, I almost remember hearing something about that before too. I like how b5 tries correcting everyone with wrong answers, he does even know that the v6's have timing belts.

 

what a nice day it was today sun shining me sat in my chair and nothing to do[:@]but at least I have one hand free and its by best for a right hookso cool it guys and enjoy

 

It's a little off-topic but I asked because a buddy of mine currently owns the green 2g dsm in your signature.

 

A stone cold motor is going to give you low compression. I have learned on german cars thermal expanison plays a big role in piston ring seating and piston size. But do a CLT. No running issues right?