02 Jetta VR6 makes Rattling Noise

I noticed a rattling noise in the engine area anytime I "give it the gas". It's worse between 40-50mph. It seems to be worse depending on how cold it is outside. I drove it 3 hours one day and at the end of the trip I could barely hear it. I've taken it to VW dealership (they are worthless) and a friend who owns a car repair place. He said the only way to find the problem was to tear down the engine and that would cost $800+. He put in thicker oil which didn't help much. Any ideas/suggestions?

Reply to
cwhitmore
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What octane gas are you using? Does it do it with high test gas? It it noisier when it is cold like 20C or is it noisier when it is warm like

20F?
Reply to
Jim Behning

I thought it was the gas as well, but I've even gone to different gas stations and have only been using super unleaded (93). Yes, it seems to be noiser when it's colder outside (but it still does it whether it's warm or cold). I noticed it in October when it started to get cold outside. It doesn't seem to be as loud after a 2+ hour trip. I thought there might be some carbon loose inside the engine so I've gunned it a few times to see if I could flush it out, but no luck. If I'm cruising on the highway at 70+ it doesn't make any noise. It's only city driving when I notice it.

Reply to
cwhitmore

I am going to send the injectors from my truck off for flow testing and cleaning. The truck pings a lot more than it did 250,000 miles ago. Relatively fresh valve job, cylinders look good, catalytic onverter looks ok on either end. There are folks that offer on the car injector cleaning. I want measured results before I go on to other troubleshooting efforts.

Your car has a diagnostic port. If somethng is goofing up it should toss error codes. On my truck which was made before the fancy easy to read dignostics codes has a knock sensor. If my truck is running too lean because of a goofed up injector that causes the knock sensor to roll back timing then that might explain the loss of power.

Another note. My 80-84 Rabbits seemed to eat catalytic converters even with new injectors. The convertor would rattle like there were marbles in the convertor. That was until a chunk big enough to cork the exhaust broke off.

Sometimes belt bearings can make weird noises that get quieter when they warm up. On the TDI you are supposed to replace all timing belt idler pulleys when doing a timing belt. My alternator/power steering belt needs a new tensioner as it is a bit noisy. Sometimes I notice it and sometimes I do not.

Back to my truck. It was making some weird rattle noises. I finally replaced the timing chain and its idler rub plates. One of those rub thngs had disintegrated. Truck was quiet again after that part was replaced. That is except for the pinging from the too lean injectors. ;-)

Reply to
Jim Behning

Yeah it could be a bad batch of fuel.

I sent a '01 GTi VR6 to the dealership. It had a slight rattle noise and I think the dealer said that the engine needed work. I believe the noise is coming from the timing chain area so that is what I think the problem is, the timing chain. This engine only has 56K miles on it and is still under warranty for the owner who is the original owner. They have to prove that the oil changes have been done regularly, so I will see what happens since they do have proof. Dealer has been nice so far, but quoted the owner $3300 if they could not provide the proof! 8^o

You need to listen to where that rattle noise is coming from. I used an auto stethoscope to determine it was in the timing chain area.

later, dave (One out of many daves)

Reply to
dave AKA vwdoc1

Reply to
none2u

How would I use the stethoscope if the noise only happens when I'm going 40-50mph?

Reply to
cwhitmore

Well obviously you would have to remove the hood, get someone else to drive while you straddle things as your co-driver gets up to speed. Well that sounds dangerous. Just go to the dyno shop, pay $100 or whatever their dyno fee is, put the car in drive and have someone rev it up to 45.

Not game for the dyno? With a stethoscope you can hear stuff even at idle or off idle in neutral that you might not hear normally.

Reply to
Jim Behning

Didn't that year VR6 have a timing belt?

Reply to
Tom's VR6

Reply to
dave AKA vwdoc1

lol thanks Jim! Yes you could hear more with a stethoscope while you are increasing the speed of the engine. Now either the noise will be there when you increase rpms or it could be the engine needs a load on it.

Dyno time or an electronic stethoscope. Some shops may have them. I think they are kinda like a remote microphone that would attach to an area so you could listen for engine noises while SAFELY driving.

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a really inexpensive one under $25
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Of course I don't want you over the engine with the hood removed while someone else is driving! But take pictures if you do and post them!!! lol

later, dave (One out of many daves)

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Reply to
dave AKA vwdoc1

Reply to
Lost In Space/Woodchuck

Here is a very interesting idea from someone on a vw message board. What do you all think about his answer?

"the noise you hear is most likely the sound coming from the Variable Geometry Intake manifold feature: in essence, it's a tuned air chamber that uses harmonic resonance to increase air flow within the intake system, effectively pushing in more air to create more power/torque.

There is a rod that rotates within the manifold to open and close this resonance chamber. It opens and closes the chamber according to engine rpm; you may have noticed that the engine sound changes around 4000 rpm, that's the VGI at work. Problem is, the plastic bushings that the rod rotates on are crap. They are too soft and due to the vibrations, become deformed and loose, causing the rod to rattle. This is most noticeable around 3000-4000 rpm under light throttle, which is around

40-50 mph in 4th gear."
Reply to
cwhitmore

Yes, very well could be the cause... as I have replaced a few.

Reply to
Lost In Space/Woodchuck

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