04 A4 Tdi rattling when idle.

Lord Nikon · 09-08-2010 2:21pm #1

It started Wednesday when I picked my girlfriend up from the airport, car was perfect on the drive there, 50 mile drive. Spent about 40 minutes in the airport, left and things went sour.

1. Battery light on dash flickered, when I went over 2500rpm, through all gear changes.

2. Car felt like it lost power completely, for a fraction of a second, when driving normally.

I couldn't really start checking the car for anything that day, I was busy in the house, and I'd worry about it on the Thursday. Thursday issues up to today...

1. That battery light flickering has gone now.

2. Rattling noise from engine compartment, can be heard from in the car, only on idle. If I tap the accelerator pedal it goes away.

3. Rattling noise happens when the car is under no stress, idle, and gear changes when releasing the clutch.

4. Squealing noise when the steering wheel is locked in either position.

Car is running perfect, no power issues at all. Timing belt, waterpump, and tensioners all done less then 5k miles ago.

Any ideas?

Moanin · 09-08-2010 2:41pm

I'd say your alternator is knackered.Have a mechanic look at it.

delynet · 09-08-2010 2:52pm

Something like this happened my 02 A4. When I turned the steering wheel I heard a screaching noise, did this for a few weeks. Was in Belfast one day and was coming home, went around a bend and lost power, lights on dash. Got home and got mechanic to check and the bearing linking the alternator to belt was gone. Some sort of freewheel thing to stop the alternator from spinning the wrong way

Mechanic said that I was lucky the thing did not come off as it sometimes does and sends the bearing out through the radiators. Cost €30 I think and he said its a common problem.

mickdw · 09-08-2010 3:49pm

I dont know about the flashing battery light etc but if you had the rattle in the engine at idle without any of the other problems, I would have said that it was your flywheel that was on the way out if your car has a dual mass flywheel.

Given all the other issues, it may well be an issue with a belt driven component as stated above

king_of_inismac · 09-08-2010 4:30pm

Definitely not tappets mate.

Sounds like something on your aux belt, which runs your alternator.

It's probably the pulley on the alternator itself. Get it fixed asap before it breaks and you lose power steering and the alternator while driving.

If you get it fixed soon, you might be able to save the alternator and just replace the pulley.

The battery light is coming on because the alternator isnt charging. The noise you hear is the alternator pulleys bearings eating themselves!

04 A4 Tdi rattling when idle.

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