Yet another edition of "What's that noise" (videos inside)

I noticed this noise coming from the engine after starting it yesterday. It seemed to have gone away after a bit of driving. I drove the car two more times that day about 3 to 5 miles and didn't hear the noise again. This morning the noise has returned and didn't go away while driving. I don't really know how to describe it, so I took a couple videos.

In the first video I left the engine cover on and it sounded like the noise was coming from the front of the engine bay. For the second video I took off the engine cover and it sounded like the noise was coming from the cylinder head. I raised the RPMs a bit and it does seem like the noise changes based on RPM.

Has anyone had this noise before? What could it possibly be. Any help is appreciated.

https://drive.google.com/file/d/129729vAx9AIq6YeVC796Hwv9fuodILzk/view?usp=drivesdk

https://drive.google.com/file/d/14m3nGFg8AM87YJrDdgJ3xxfrqt9sujNm/view?usp=drivesdk

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Either googl no worky or the files are huge. It just spins
pics.tdiclub.com

Worked for me when I got on my pc vs. mobile. Did someone install a vacuum cleaner on your car? Cause that's what it sounds like lol


Noise was loudest when you were above the power steering pump. I'd start by pulling the serpentine belt off and fire it up again, see if it goes away. That'll eliminate all your accessories.

I agree you should first take off the serpentine belt off and see if the noise goes away. You can take the belt off and start the engine. It will run no problem. Just the no battery charge, A/C, or power steering so don't drive it around for too long.

I had a similar noise (when cold but goes away when warm) but it was in my timing belt path. I did a full timing belt job with all new rollers and tensioner and the noise went away.

My guess is one of the roller's bearings (serpentine belt path or timing belt path) is wearing out.

The noise has been somewhat intermittent and seemed to be a tiny bit louder today.


I'm gonna go ahead and remove the serpentine belt this weekend. It's funny because just a few weeks ago I had to do this to diagnose and replace a bad alternator pulley. I replaced the idler pulley, tensioner and belt as well. Every pulley seemed to be fine, but we'll see what happens.



I really hope it's not anything in the timing belt path. I only have about 30k on this timing belt kit.

Sounds like bearing noise to me, but my laptop speakers are crap. Definitely take the serp belt off and see if it goes away, don't delay though, could be catastrophic if it's a roller on the t-belt.

Lurker,
Something's up with his car, overboosting?

On 16" rims, look around for "Le Castellet". Came standard on VR6s. There's a set advertised locally for $150.

Rrusse11, I think you replied to me in the wrong thread . Thanks for the tip on the rims though.

VE1.9 said:

The noise has been somewhat intermittent and seemed to be a tiny bit louder today.

I'm gonna go ahead and remove the serpentine belt this weekend. It's funny because just a few weeks ago I had to do this to diagnose and replace a bad alternator pulley. I replaced the idler pulley, tensioner and belt as well. Every pulley seemed to be fine, but we'll see what happens.

I really hope it's not anything in the timing belt path. I only have about 30k on this timing belt kit.

Click to expand...

The belt might be fine, but the bearings on the tensioner/roller might not be. That's what happened to me. The belt had 60K on it and it looked fine (except it was a tiny bit thinner) but one of the bearings was definitely making the noise. Once I replaced all pulleys/tensioner the noise went away. This time I got the best tensioner/rollers I could get. Hopefully it'll last 100K.

I wanted to post up an update since I figured out and solved the issue over the weekend. I hope this helps anyone who has the same issue.

I removed the serpentine belt and briefly ran the engine. The noise was gone so it had to be one of the components along the belt's path. As I mentioned earlier in the thread, I had replaced the belt, tensioner, idler pulley, and the alternator pulley about a month before this noise began. After checking all the pulleys, I noticed the alternator pulley had more rotational resistance than it should have, so I figured it must have a bad bearing. This seemed odd because when I had replaced the pulley a month before, it spun normally without major resistance.

I ended up finding a rebuilt alternator in junkyard Jetta. It looked to be a freshly remanufactured 120A Bosch. The thing still looked brand new and the pulley had a manufacture date from october 2017, so it seemed like a nice score. I installed it this past Saturday and to my dismay, the battery light on the cluster stayed on after starting the car, and the voltage at the battery was around 11v, so this alternator was bad. Since my alternator only seemed to have a bad bearing, I decided to swap over the bearings from the rebuilt alternator. I also ended up swapping over the slip rings since mine were fairly worn and the ones on the rebuilt unit looked brand new. I also noticed that my voltage regulator's brushes were actually past the 5mm wear limit, so I replaced it with a good spare that I was holding onto for exactly this type of situation.

In the end, I basically ended up rebuilding my own alternator and installing it back on the car. I had to do the job twice, but in the end it's worth it since I replaced nearly every component that can fail in an alternator. I expect this one to last a good long time.



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Nice! You've got the makings of a real fine HOW-TO right there