Intermittent Noisy Engine - Audi A6 estate - 1.9 Tdi

[Hairymary]

Hi guys
My car is about 5 yrs old - an 03 plate. The 1.9 Tdi has been faultless and has done about 52,000 miles and has been serviced regularly. It suddenly developed an intermittent rattling noise at the front of the engine, noticeable at low speeds, and mostly when parking, manoevering etc.

My friendly competent mechanic immediately diagnosed a faulty power steering pump that was noisy when working hard. He identified the problem by putting the front wheels on full lock whilst stationary and the noise started, so a reasonable diagnosis. Replaced it but no improvement ! The next logical thing to replace was the belt tensioner, a tricky time consuming job including a bracket and pulley, and a small damper device.

The only logical conclusion is that the fault has been mis-diagnosed and I have replaced parts that didn't need replacing. I have still got the problem and my wallet is much lighter ! By the way, all parts replaced with Audi parts, with the exception of the power steering pump.


Anyone had this problem? Any ideas before I take it to an Audi dealer ?

Thanks in advance
Mike

 

[Belle427]

difficult to diagnose over the internet but has it had a timing belt change yet?

 

[^neo^]

Check the exhaust heat shield

 

[Hairymary]

No, the timing belt has not been changed.
Thanks

 

[captain_scarlet]

did you replace the p/s alternator etc drive belt? you may have changed the tensioner but if the belt is a little stretched or the ribs are worn it can cause the tensioner to rattle and vibrate giving the noise your getting. try to watch the movement of the tensioner with the engine running. difficult to describe how much it should move, but with everything in good condition movement should be slight. but more than say 10- 20 millimetres the belt isnt being tensioned enough.

 

[libby lou lou]

Check the exhaust heat shield

you should also do the cheapest first.

P.S.was it a new pump, recon or off a damaged car,or anything else that could help?

 

[davieboy]

timing belt tensioner very prone to breaking up on these. there are modified parts available from audi/vag. the plunger assy waers the tensioner where they contact, when it fails the belt goes slack, timing jumps and valves get bent. have it checked now by a competent mechanic.

in fact on that mileage i would change the timing belt, tensioer assy and relay roller as a matter of course, its not hard.

 

[jav]

could u keep us posted on wot happens, i'm having a similar situation, tnx.

 

[Hairymary]

Ok this is the definitive answer, as fixed by the Audi dealer today.

They diagnosed a siezing alternator pulley mechanism. The freewheel pulley (which has some sort of clutch mechanism on it) was replaced and she is now running very sweetly.
So, in the end, quite cheap compared with all the other stuff I have had replaced for no reason.
Should have gone there first, but having said that I can see how the symptoms made the diagnosis difficult. This was definitely the case that superior Audi product knowledge helped to correctly diagnose the problem.

Thanks for your replies and your interest and hope this helps someone else
Mike