A3 'AUM' 1.8T, cam chain problem
Discussion
Hi guys! I've recently done a cambelt change on an Audi A3 AUM engined 1.8 turbo and starting to wish I'd never seen it. The car came to me with an EML showing 2 codes.... 1 was turbo pressure loss (found a leaking pipe) and 1 that I hadn't seen before was camshaft position reading early and late advancing / retarding.
I changed the cambelt which was due and running slack / worn and since then I've had it running but with a tapping at the top end. Satisfied that the timing was right after checking a dozen times
I lifted the camshaft lid cover and found an oil damper / tensioner running underneath the cam chain inside the top of the engine which turns the secondary cam. What is happening is the chain is being allowed to go slack just before tdc on cam 1 and the chain bows to the point that when cam 2 finally sits down the damper 'pops' back in making a loud click noise. I've checked for compression and getting random readings but I'm convinced there has not been any interference ......... SO FAR!? 
I've done tons of these cambelts before and never had a problem but Audi, in all their helpfulness as usual, reckon it's a common problem on the earlier Passats yet have not heard of it before on an A3. Their solution is to chuck an new chain and damper in to it at a cost of over £500 for the parts alone. (plus the grief of me getting the engine mount out again and starting from afresh)
Any suggestions would be greatly appreciated as I'm 2 steps from dousing it in petrol and setting light to it!!!
I was told today that the owner changed the oil in it recently and he used 5w/30 and as it was running OK when it came to me albeit it with the EML on so I'm assuming that it isn't just a hydraulic problem with the VVT. Is it possible that the secondary camshaft has moved slightly? I can't see how as cam 1 was timed up right as per Audi's marks on the cam itself and therefore cam 2 shouldn't have moved as it's linked to the chain when at TDC. Can anyone shed some light?
Pretty please?????????
I changed the cambelt which was due and running slack / worn and since then I've had it running but with a tapping at the top end. Satisfied that the timing was right after checking a dozen times
I lifted the camshaft lid cover and found an oil damper / tensioner running underneath the cam chain inside the top of the engine which turns the secondary cam. What is happening is the chain is being allowed to go slack just before tdc on cam 1 and the chain bows to the point that when cam 2 finally sits down the damper 'pops' back in making a loud click noise. I've checked for compression and getting random readings but I'm convinced there has not been any interference ......... SO FAR!? I've done tons of these cambelts before and never had a problem but Audi, in all their helpfulness as usual, reckon it's a common problem on the earlier Passats yet have not heard of it before on an A3. Their solution is to chuck an new chain and damper in to it at a cost of over £500 for the parts alone. (plus the grief of me getting the engine mount out again and starting from afresh)
Any suggestions would be greatly appreciated as I'm 2 steps from dousing it in petrol and setting light to it!!!
I was told today that the owner changed the oil in it recently and he used 5w/30 and as it was running OK when it came to me albeit it with the EML on so I'm assuming that it isn't just a hydraulic problem with the VVT. Is it possible that the secondary camshaft has moved slightly? I can't see how as cam 1 was timed up right as per Audi's marks on the cam itself and therefore cam 2 shouldn't have moved as it's linked to the chain when at TDC. Can anyone shed some light?
Pretty please?????????
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