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Discussion Starter #1
Hi all,

About a week ago my 2.0L AEG engine started making a low rumbling/growling sound. It seems to be coming from underneath the engine or below the front area, and I can feel it vibrate most of the front dash area when it happens. It's a bit like a ricer car's loud muffler, but it's coming from the front area not the back.

It only happens during idle, and when I step on the throttle to accelerate. If I just let off the throttle (while still in drive) and coast, then it does not happen. Also when I accelerate it feels kinda sluggish now.

I scanned it and initially got code 17988 (P1580 throttle bank 1 malfunction). So I cleaned the throttle plate and did a TBA, cleared the codes and went for a short test drive. The rumbling was still there.

I then did a full scan again and no more codes - nothing. So I'm not sure where to look now. Any ideas anyone?
 

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5/23/10 <3
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Maybe an exhaust leak or failing catalytic converter?
 

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Discussion Starter #3
Maybe an exhaust leak or failing catalytic converter?
Any tips on how to test for those? Searching forum I get these tricks:

For testing the cat, I read here to shake it and see if there's anything inside rattling, if so it's dead. Any other tips?

For exhaust, I also read a couple of methods. One is to plug up exhaust pipe with a rag while running and feel/listen for leaks.

Another method is to hook up a vacuum to the exhaust and turn it on, then feel/listen for leaks.

Any other methods? In theory I like using the vacuum method because it seems a lot safer (no fumes and no hot parts), however I'm guessing it's probably harder to find the leak that way say it's harder to feel/hear air going into a leak, as opposed to feeling air being pushed out of a leak through the back pressure would probably be easier (using method 1).

I'm gonna try to tackle it this weekend. If anyone else has any tips that would be greatly appreciated. Thanks.
 

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Discussion Starter #5 (Edited)
motor mount?
I'm a noob mechanic so please bear with me, where is the motor mount exactly and what should I be looking for? I guess I'll try to see where the motor bolts to the frame, I guess right? If I find it, what should I do, just try to tighten the bolts or something?

**EDIT** Ok I looked up some timing belt DIY and saw the passenger side engine mount, it's a triangular block type thing, but where are the other ones located? Also I'm still not sure what to look or check for with the mounts. Should I just test and hold them and see if the noise stops (in my case I'll probably press a block of wood or something, I'm a noob so I don't like sticking my hands into the engine when it's running).
 

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There is one mount on the drivers side, just like the passenger side. And one under the transmission that goes towards the back of the car.
 

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running engine

Not a good Idea to be sticking hands or boards when the engine is running..LOL :D Do a goodle search for the new beetle motor mounts using the image selection and it'll come up with hundreds of pictures of the mounts so you'll know what to inspect, engine turned off of course. Good luck
 

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I'm a noob mechanic so please bear with me, where is the motor mount exactly and what should I be looking for? I guess I'll try to see where the motor bolts to the frame, I guess right? If I find it, what should I do, just try to tighten the bolts or something?

**EDIT** Ok I looked up some timing belt DIY and saw the passenger side engine mount, it's a triangular block type thing, but where are the other ones located? Also I'm still not sure what to look or check for with the mounts. Should I just test and hold them and see if the noise stops (in my case I'll probably press a block of wood or something, I'm a noob so I don't like sticking my hands into the engine when it's running).
I doubt it is your motor mounts but you can try and push on your engine (while it's off) and see if you get any movement especially back and forth. Now your sounds your are getting aren't clunking sounds? More like exhaust sounds or engine sounds. I would open the hood, take off the plastic engine cover turn on the car and then listen. Give it a little gas and see if you can trace the sound. Could be an exhaust leak or a vacuum leak. If there is a rattling noise coming from underneath the car it could very well be the catylitic converter. The ceramic inside breaks into little chunks and cloggs up the exhaust pipe causing major back pressure and loss in performance.
Also check for anything loose under the hood. Wiggle your radiator from the top and below. I had one of the bolts missing on mine and there was excessive movement until I replaced the bolt.

Good Luck and keep us posted.

PS: If it is more like a clunking sound it more than likely is caused by your worn out sway bar bushings. It's the first things I replaced when I got my car. Makes a world of difference.
 
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