ORKA64.2

Dear AudiWorld,

I have a 03 A6 4.2 with a P0346 code (No VAG) & it has been happening since I had the TB done @ 80K at an indy shop. I had the sensor replaced a couple months ago, drove it 18K & the code has come up again accompanied by the CEL. Another noticeable attribute I the car has had post TB service is a rattle on cold start up. I've looked into this subject and have yielded a headache with few conclusions if any, so I figured it'd be worth the inquiry to Audiearth to see what my problems could be.

Is it the cam chain tensioner?
Could the new OEM sensor be kaput?
Could it be a solenoid valve? IDFK
Is trusting your Audi to a Mechanic, like trusting your rights to a Lawyer, your health to a Doctor or your soul to a Preacher?

I am taking the car in to get fixed in a couple days and would appreciate any input so I know what to go for in the engine/ car without wasting Time/ Legal Tender.

DISCLAIMER: I googled until my head hurt, I'm very busy and I am the opposite of a mechanic. Thank you for your Time.

N_Jay

I don't know much about the Audi engines yet, but rattle on cold start after a Timing belt change is either a bad tensioner or mis-timed cams.
Neither is good.

SloopJohnB@mac.com

Bad tensioner often is the result of worn/missing/broken shoes on the tensioner…the shoes can be replaced for $20 or so plus gaskets, etc., labor.

4Driver4

Timing belt job was botched. Did they use the special tools?

ORKA64.2

I would hope so, they're the pros and I paid. I brought it back right away to harp about a few points, that being one and the shop struck me as pros yet again. I have taken my car to them a lot and the whole experience has been good, so I'm not inclined to think they messed it up, but who knows. Could it only put out one code if it was botched? Would botching it make the cam tensioner go? Could I really drive it across the country 3 times if it was messed up? What could they have done wrong in particular when doing the TB that could cause this? Thanks for the input.

ORKA64.2

How many of hours does it take to replace the shoe roughly? Thanks

SloopJohnB@mac.com

I would think if you drove it across the country three times after the TB job it was not messed up and your tensioner or shoe failure/wearout was coincidental.

SloopJohnB@mac.com

About the same as replacing the tensioner…the tensioner comes out, the new shoes are snapped on, and the tensioner replaced. Maybe a few minutes more per tensioner to snap on the new shoes.

The problem of course is determining if the tensioner is bad….but if the shoes are worn/missing when the tensioner(s) is/are pulled out, the problems is likely to be the shoes. I'd guess maybe 6-8 hours for both banks. With high mileage engines, it's also a good idea to check the cam chain for stretch (measure 10 links next to a new chain, much like a motorcycle chain…I'd guess more than two-four mm difference should have a new chain). As on a motorcycle chainring, if the chainring is cupped significantly, it's time to replace the chain ring(s) as well unless they're an integral part of the camshaft…in that case I would just replace the cam chain since replacing the camshaft involves replacing followers, etc. and can run into significant additional cost.

ORKA64.2

Yeah, I drove 18K +/- post TB service. I got the code & CEL right after service, replaced camshaft sensor only to get code & CEL 18K later. Rattle on cold start up began the day after TB was done and has been happening since.

ORKA64.2

Thanks for the gems. The engine has under 100K, and I was initially quoted for replacement of the entire tensioner. If the mechanic doesn't bring up the tensioner shoes firstly, would that be grounds to get a secondary opinion? It sounds a lot cheeper to do just the pads.