Howling noise under hood

So my '01 Jetta is making this howling noise, likely a bearing of some sort, but I can hear it best at 1600 rpm when I put my head around the power steering reservoir.
I'm hoping it's the AC compressor. I did the TB at about 230K I think, car now has 266k on it. Did all the usual stuff when I did it, water pump, etc.
Looking for ideas.

Remove the serpentine belt, and run the car. If the noise is gone, you're
narrowed down to that track. You'll get a battery light, but no biggie. Just
remember to put it back on before you go out of town!

Well, I removed the auxiliary belt and the noise persists. Looks like it's TB related. I just did the TB about 40k miles ago. I'm hoping it's something simple like an idler but are there any usual suspects to look at once I get in there? Like, once I get the belt loosened will it be obvious which component is going bad?

Where did you get the parts from?
Saving money on TB parts can cost more if any one part fails.

wonneber said:

Where did you get the parts from?
Saving money on TB parts can cost more if any one part fails.

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idparts.

Take the timing belt cover off and inspect.

IDParts has been my go to for these parts as well. Shy of 60k in to my 100k kit, my waterpump developed a bad leak that required a premature timing belt job. I was NOT happy about that.

I went with their kit again in hopes that it might last 80-100k, although I'll always do it prior to 100k. If this one fails early I'm going to have to look at other kits. Under 60k out of a 100k advertised kit is simply unacceptable to me. Unless it's half off.

KrashDH said:

IDParts has been my go to for these parts as well. Shy of 60k in to my 100k kit, my waterpump developed a bad leak that required a premature timing belt job. I was NOT happy about that.

I went with their kit again in hopes that it might last 80-100k, although I'll always do it prior to 100k. If this one fails early I'm going to have to look at other kits. Under 60k out of a 100k advertised kit is simply unacceptable to me. Unless it's half off.

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I don't know when you installed the waterpump that failed, but I feel there was a bad batch of them 10 years ago. Mine died with a bad bearing and shaft froze at 98K in 2014, but that kit was installed in 2010. Some others found a failure way before that mileage. It didn't seem to me to be a widespread problem. I went with another kit from them because I've not ever had a problem on the kits I have purchased from them or the countless ones I have installed for customers who I have done work for.

jokila said:

I don't know when you installed the waterpump that failed, but I feel there was a bad batch of them 10 years ago. Mine died with a bad bearing and shaft froze at 98K in 2014, but that kit was installed in 2010. Some others found a failure way before that mileage. It didn't seem to me to be a widespread problem. I went with another kit from them because I've not ever had a problem on the kits I have purchased from them or the countless ones I have installed for customers who I have done work for.

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So I bought the car in/around 2015, drove it for a few months when the shaft of the WP snapped clean off. PO had all the paperwork for the TB job that was done, it was around 70k at the time (100k kit). Then I did the job myself with the ID parts kit (2015-2016 ish, I have the records at home not as I type this) and the WP again started to leak bad under the 60k mark, which was last year. I wasn't going to let it go much longer after I caught it leaking. So the newest kit I bought from them I installed last summer (2018). We'll see what this one does.

Another thing you can do is to remove the accessory serpentine and listen. You might get a light for the alternator, but the battery will keep things going for a while anyway.

That way you can at least tell whether the noise is coming from something in the timing belt loop vs the serpentine belt loop.

Cheers,

PH

Powder Hound said:

Another thing you can do is to remove the accessory serpentine and listen. You might get a light for the alternator, but the battery will keep things going for a while anyway.
That way you can at least tell whether the noise is coming from something in the timing belt loop vs the serpentine belt loop.
Cheers,
PH

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I think he did that in post #3

Oops, you're right. My bad...

PH

check for dogs

How long has this gone on? Since the timing belt operations?
One howling scenario is if the timing belt gets put on the wrong side of the small lower idler roller. The timing belt lugs will roar.

I have this car up on the ramps now, have the accessory belt off and had my wife run the car for me. It's really apparent at about 1600 but one can only hear it from inside the cabin, I'm standing outside with my head in the engine compartment and I can't discern the noise itself, much less where it's coming from.
One thing she and I agree on is that when the car is on the road there's a deeper toned noise similar, probably associated, who knows.
IIRC the car has always had this noise (or noises) ever since I resurrected it out of a field but it seems to be developing.
That rescue involved a TB and a new 02J transmission, among other things. That was at 220k, car now has 266k on it.

Since it hasn't been asked yet, have you checked if any of the EGR pipes have cracked or are leaking? They can cause a similar noise, and get louder when under load.

Nero Morg said:

Since it hasn't been asked yet, have you checked if any of the EGR pipes have cracked or are leaking? They can cause a similar noise, and get louder when under load.

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This particular car has no EGR per se. The cooler is there, but no coolant goes thru it. It came to me blocked off, presumably for a leak.
That's a good idea though.