alightman

Got my '02 S6 back yesterday from trusted indy, replaced oil cooler due to coolant leak. Drove 50 miles home, everything great. Started fine this morning, ran some errands close to home, pulled into driveway with car making a bad noise. At first I thought it was an exhaust leak, but it kept up at idle. It's left side valve train, like there's no oil. Pressure is good, level is good. Put it on a flatbed and sent it back, I won't hear until Monday. Is it possible that something came loose during replacement and blocked passage to just that side? Right side sounded fine. I know it's a 5 hour job, so a lot must have come apart. Car has been running great aside from the leak. Any thoughts from the wise men?

SloopJohnB@mac.com

There is no relationship between valve noise and that oil cooler coolant transfer tube replacement. I've done it twice on the 2K4.2A6. Only thing that is remotely connected to the oil system is you have to remove the oil filter (I drain and change the oil, but not necessary) to get to a few things.
BTW..the left side is generally the driver's side; the cooler coolant transfer tube is on the right side, the passenger side in LHD cars in North America.

alightman

Current suspect is "check valve" that keeps oil from draining from the head when not running. Took a week to get the part, wrong one arrived, correct one on the way. Tech agrees they should not be related, but that it is really coincidental. I'll post the result when I know (soon I hope)!

Prospeeder

Probably cam chain tensioner failing and making noise. 4.2s are known for this.

SloopJohnB@mac.com

Try changing oil to 15W-40. Chances are you're running 0W-30 or 5W30….
I know I have a cam tensioner issue (code comes and I cancel it) but it went away with 15W-40 amsoil synthetic…(it's a diesel/marine gas oil, doesn't meet 02S6 standards but it's ok for 2000 4.2 engine). One of these days I'll change out the tensioner or it's most likely the plastic shoes….

I run 5W-40 Euro formula on my S6….


Fair disclosure..lifetime Amsoil dealer.

alightman

Saga continues, got the car back today after 5 weeks. After trying check valves, tensioner and other parts, nothing worked. Pulled the head, some kind internal oil block on exhaust lifters. Consult with local dealer head mechanic, never seen anything like it. Choice was new head from Germany for $3100 installed, or used engine with 61,000 miles from a crashed from the rear 2003 S8 for 4K$ total. My car was nearing 140,000 miles, so I rolled the dice and went for the used engine. Runs great, I swear I can feel the extra 20 hp. We'll see as time goes on. I've driven 500,000 miles on 3 different quattros with no major problems, so I guess I'm due. Still, it's a little disconcerting.

Airbag

no realtionship between an oil cooler transfer pipe work and a blocked oil passage ? hmmm... yo just gotta think they did SOMETHING
maybe even a bad oil filter ? did they change the oil at the same time ? .. i dont believe in those type of coincidences

Nialist

+1 As I had this as a problem shortly after last tb service. Sounded like a rhythmic ticking, or slapping-type of noise when idling with all engine covers on and hood shut. Turned out the tensioner was failing and making the noise i described.

SloopJohnB@mac.com

Did they say why not replace lifters and cams?

alightman

I agree, has to be connected somehow. They did change the oil and filter, looked closely at them, no smoking gun. The mechanic even thought it was too big a coincidence. These guys have taken pretty good care of me, did a no charge timing belt on the new motor and some other free labor.