Home Technical Discussions Volkswagen Jetta, Golf, GTI: 1985-1992 (A2)

Volkswagen Jetta, Golf, GTI: 1985-1992 (A2) [1991 Jetta GL; AT; CA Emissions] Whirring noise when accelerating


Permlink Replies: 17 - Pages: 1
Last Post: Oct 17, 2011 9:36 AM Last Post By: tcovenant2000
s2zeller

Posts: 160
Registered: 12/09/03
[1991 Jetta GL; AT; CA Emissions] Whirring noise when accelerating
Posted: Aug 8, 2011 9:45 AM
  Click to reply to this thread Reply
I just started noticing a high pitch whir/whistle (not constant pitch, and a bit rhythmic... definitely not something I'd call a squeal) when I accelerate after starting the car from cold. The sound definitely coming from the front of the car and goes away after about a mile of driving.

Could this be a belt (and/or pulley) issue? Would a shot of silicone to the pulleys be worth trying?

Or is there something else I should be looking at (since it only happens on acceleration, it will be a bit hard to look under the hood at the time :P)?
tcovenant2000

Posts: 1,802
Registered: 12/09/03
Re: [1991 Jetta GL; AT; CA Emissions] Whirring noise when accelerating
Posted: Aug 9, 2011 12:49 AM   in response to: s2zeller in response to: s2zeller
  Click to reply to this thread Reply
Sounds like it's a vacuum leak, but maybe not if only when cold. I'd look at the hoses connecting the ISV. One of them does a 90 degree turn and cracks are well hidden unless you prod it a bit.
Does it do this when accelerating only? Or when revving the engine in N? If only on acceleration, I'd lean toward drive train components. But this also smacks of pulley or belt.
Here's another thought: The CA emissions package requires two sources for your intake air (coming into the bottom of the air filter box). When the engine is cold, air is supposed to be pulled from the hose going to the exhaust manifold. When warm, air comes from the hose going to the grille. It's possible you have restrictions in the hose going to the manifold, or maybe more likely that you have a broken diaphragm on the flapper inside the airbox, or some sort of problem with it such that when it's supposed to be "closed" (pulling air from the manifold), it's actually not really closing all the way. Or blockage in that line. You might look there.

Thomas
s2zeller

Posts: 160
Registered: 12/09/03
Re: [1991 Jetta GL; AT; CA Emissions] Whirring noise when accelerating
Posted: Aug 9, 2011 6:53 AM   in response to: tcovenant2000 in response to: tcovenant2000
  Click to reply to this thread Reply
I definitely only heard it after accelerating from cold yesterday,but I was going to see if it does it while revving in N this morning.

I'll also pay better attention today to see if it happens any other time.
s2zeller

Posts: 160
Registered: 12/09/03
Re: [1991 Jetta GL; AT; CA Emissions] Whirring noise when accelerating
Posted: Aug 9, 2011 9:42 AM   in response to: s2zeller in response to: s2zeller
  Click to reply to this thread Reply
No odd sound at all this morning... which jibes with my wife having heard it once a couple of days before I did.
tcovenant2000

Posts: 1,802
Registered: 12/09/03
Re: [1991 Jetta GL; AT; CA Emissions] Whirring noise when accelerating
Posted: Aug 9, 2011 2:11 PM   in response to: s2zeller in response to: s2zeller
  Click to reply to this thread Reply
Yeah...I hate these intermittent ones. That begins to sound more like belt, which would happen more when cold. Pay attention. This could be as simple as a power steering belt that squeals only when you turn the wheel (i.e. not when revving in N) and only when cold. Hope for the easy fix!

Thomas
s2zeller

Posts: 160
Registered: 12/09/03
Re: [1991 Jetta GL; AT; CA Emissions] Whirring noise when accelerating
Posted: Aug 9, 2011 9:36 PM   in response to: tcovenant2000 in response to: tcovenant2000
  Click to reply to this thread Reply
I think I heard it this afternoon after sitting out all day at work. The sound was a bit different, not so rhythmic and more constant and more like a muffled higher-pitch squeak.

It didn't seem to last as long, and it did happen (tho' seemed quieter) when I shifted into N and revved.
JGr

Posts: 67
Registered: 05/20/10
Re: [1991 Jetta GL; AT; CA Emissions] Whirring noise when accelerating
Posted: Aug 9, 2011 9:48 PM   in response to: s2zeller in response to: s2zeller
  Click to reply to this thread Reply
Maybe water pump going bad,not sure
tcovenant2000

Posts: 1,802
Registered: 12/09/03
Re: [1991 Jetta GL; AT; CA Emissions] Whirring noise when accelerating
Posted: Aug 10, 2011 1:33 PM   in response to: s2zeller in response to: s2zeller
  Click to reply to this thread Reply
Yeah...I think you're looking at a bearing or belt issue. It will get worse and eventually you'll find it. I'm looking at a new alternator for my wabbit, as the bearing is getting squealy.

Thomas
s2zeller

Posts: 160
Registered: 12/09/03
Re: [1991 Jetta GL; AT; CA Emissions] Whirring noise when accelerating
Posted: Aug 16, 2011 7:03 AM   in response to: tcovenant2000 in response to: tcovenant2000
  Click to reply to this thread Reply
Well, it is becoming a little more prevalent, though still not happening every time I start the car from "cold" (i.e. it initially happened only after sitting overnight but now it happens after sitting in the sun all day at work).

The sound is also a little different. It often has what sounds like a toy electric motor spinning up/down as I accelerate. The sound stops/pauses when the automatic transmission shifts during acceleration, then resumes. It is also briefly present when revving the car in Neutral (but fads out after the first couple of seconds).
tcovenant2000

Posts: 1,802
Registered: 12/09/03
Re: [1991 Jetta GL; AT; CA Emissions] Whirring noise when accelerating
Posted: Aug 16, 2011 6:56 PM   in response to: s2zeller in response to: s2zeller
  Click to reply to this thread Reply
Are you sure it's coming from under the hood? This begins to sound like the in-tank pump may be going south.
Well...until it reaches a point where you can actually deal with it for more than a few secs there isn't much you can do.
If you're inclined, here's an idea that I've done before:
Remove all the accessory belts. All of 'em. Then start the car from cold. If the sound is gone then one of your belts or bearings are going south. Yep. It's a pain in the rear, but you'll find out sooner what it is.

Thomas
s2zeller

Posts: 160
Registered: 12/09/03
Re: [1991 Jetta GL; AT; CA Emissions] Whirring noise when accelerating
Posted: Aug 16, 2011 7:47 PM   in response to: tcovenant2000 in response to: tcovenant2000
  Click to reply to this thread Reply
It is definitely coming from the front of the car, and only sporadically when I shift Neutral.

One odd thing I noticed was that the ATF fluid is very high (i.e. above Max) as measured per Bentley. Since the noise changes with shifting, I got to wondering if the two are related...
tcovenant2000

Posts: 1,802
Registered: 12/09/03
Re: [1991 Jetta GL; AT; CA Emissions] Whirring noise when accelerating
Posted: Aug 18, 2011 7:02 PM   in response to: s2zeller in response to: s2zeller
  Click to reply to this thread Reply
I don't know about that. I mean, you very much should drain off excess auto trans fluid (be sure you are checking it when the car is hot, shift from park to every gear for a few seconds each, then back to park, again stopping in every gear for a few secs, then back to N, then pull and wipe the dipstick, insert and pull and check level). If it's too high it can foam, but not usually when warm. As it gets warm it expands, and the foaming would get worse as it warmed up. Still, it's possible I suppose. What about your power steering fluid? Is it too high or too low?

Thomas
s2zeller

Posts: 160
Registered: 12/09/03
Re: [1991 Jetta GL; AT; CA Emissions] Whirring noise when accelerating
Posted: Aug 18, 2011 10:44 PM   in response to: tcovenant2000 in response to: tcovenant2000
  Click to reply to this thread Reply
Ah, right. I forgot to shift through the gears. I'll try that the next time... and check the power steering fluid.

The car is good and warm (after an 80-mile drive) and the fluid is not foamy (it looks surprisingly good to me).
tcovenant2000

Posts: 1,802
Registered: 12/09/03
Re: [1991 Jetta GL; AT; CA Emissions] Whirring noise when accelerating
Posted: Aug 19, 2011 2:52 PM   in response to: s2zeller in response to: s2zeller
  Click to reply to this thread Reply
Yep. You gotta shift through because that fills all the little chambers with fluid to give you an accurate reading.
Not foamy is good. Clean and red and smelling fine is good. The trans doesn't have a pump, per se, so that's unlikely the source of your noise.

Thomas
s2zeller

Posts: 160
Registered: 12/09/03
Re: [1991 Jetta GL; AT; CA Emissions] Whirring noise when accelerating
Posted: Sep 25, 2011 8:32 PM   in response to: tcovenant2000 in response to: tcovenant2000
  Click to reply to this thread Reply
Too rainy to paint this weekend, so I spent it replacing 11-year old belts (alternator, PS, AC), and the squeak is still present on starting from cold. It seems to first kick in around 1700 RPM and stop around 2500 RPM then stop for good after about a mile of driving.

Anything I can do to confirm timing belt tensioner (or other)?

The pulleys on the PS pump, AC compressor (which, BTW, is largely useless since I lost refrigerant a few years back), and alternator seemed to spin freely and were cleaned while I had the belts off.
tcovenant2000

Posts: 1,802
Registered: 12/09/03
Re: [1991 Jetta GL; AT; CA Emissions] Whirring noise when accelerating
Posted: Sep 26, 2011 7:28 PM   in response to: s2zeller in response to: s2zeller
  Click to reply to this thread Reply
Really not much more you can do. What I've done in the past is to remove all the belts, then start it and listen. If no noise, then I put the belts back on one at a time until it makes noise. But that only works when it reaches a point where it's always noisy.
This could be so many things. Crank bushing. Motor mount. Pulley bearing. Cam bushing. Tensioner. I hate to say it, but you're almost going to have to wait until it's making noise all the time.

Thomas
s2zeller

Posts: 160
Registered: 12/09/03
Re: [1991 Jetta GL; AT; CA Emissions] Whirring noise when accelerating
Posted: Oct 16, 2011 9:29 PM   in response to: tcovenant2000 in response to: tcovenant2000
  Click to reply to this thread Reply
It looks like it was the timing belt tensioner. My shop noticed it had tightened itself up good and tight. After he loosened it, the noise didn't come back. Once he got the parts, he replaced it and the belt and we have yet to hear the noise again. He did say that it was probably the worst tensioner he'd ever seen that still had some functioning life in it.
tcovenant2000

Posts: 1,802
Registered: 12/09/03
Re: [1991 Jetta GL; AT; CA Emissions] Whirring noise when accelerating
Posted: Oct 17, 2011 9:36 AM   in response to: s2zeller in response to: s2zeller
  Click to reply to this thread Reply
Ah...thanks for letting us know what it was! Glad you got it figured out!

Thomas

Point your RSS reader here for a feed of the latest messages in all forums

Popular Discussions:
No popular dicussions.