big_g

My car: 2000 ws6 with 66K (nearly all stock)

My Issue: When I punch it, I get a squeaking sound from the engine, but only in the first split second. When I slightly accelerate while cruising on the freeway I get a more extended squeaking. While in park, with or without revving it? Not a sound. Makes this hard to truly diagnose...

My Suspicions: A worn out belt tensioner (it is the stock one). It is still within specs though. And would this not squeak while the car is in neutral? I have replaced both belts (Gates belts) and the belt tensioner pulley with no change to the squeak.

Before I throw money at a tensioner I may not need, any other ideas, or confirmation of my own, from you gurus?

wssix99

iTrader: (5)

I wouldn't think it has anything to do with the belts, then.


What makes you think that the engine is making the noise when it only happens when you are moving?

farmington

iTrader: (14)

if you think it may be the tensioner, hit the bearing area with a spray of wd40 while its running and listen to see if it changes

big_g

I can hear it clearly while driving. I'm guessing it is the tensioner spring because it would be under a heavier load and slap around more when I punch it with the gears engaged, no?

wssix99

iTrader: (5)

What happens when you are coasting and that load drops? Does the sound go away?

BTW - I've never heard of a weak tensioner causing noise. If you were getting belt slippage, you'd smell burning rubber, see wear on the belt, see voltage dropping off from the alternator, etc.

big_g

Yep. It only makes noise at initial "load up" of the engine when I push the pedal, or more prolonged noise while slowly and steadily accelerating. And it makes zero noise in park no matter what I do. It never makes a peep while cruising either, at any speed.

wssix99

iTrader: (5)

I wouldn't discount wheel bearings yet. When the engine is under load, weight comes off the front wheel bearings and is added to the rears. It would be interesting to see what happens in reverse, but I'm not sure how you'd do that safely...

I would not advise spraying WD-40 in the engine bay - ever. That crap will dissolve the good grease you have on pulleys/bearings and will just lead to other issues in short order. Water is probably a much better choice. However, if your belt was slipping, as I mentioned above, that should come with other issues. Folks on this site have had odd squeals from bent/knocked pulleys - but those are really a nightmare to track down. If you have a bad pulley, water might silence the thing down.

Just for kicks and giggles - have you removed the A/C belt and driven around just to eliminate that belt and its associated pulleys from the equation?

big_g

No, that is next up on the list.
It seems easiest to replicate at around 50-60mph, or when driving at like 30mph up a small hill. Maybe I should try it down a hill to check the wheel bearing theory... :-)

And it seems like it happens more often and longer under a smaller load... (like start from coasting at 55mph and a give sudden 25-50% steady throttle)

wssix99

iTrader: (5)

I was thinking the same thing as I read your first sentence! Driving downhill would be a much easier test than a drag race in reverse.


My experience is that this type of behavior is consistent with a bad bearing (somewhere) vs a belt issue. You'd think a belt problem would get worse with load/RPM.

big_g

So... I haven't figured it out yet because a bunch of other stuff came up... It happens almost all the time, with volume and length of noise seeming to depend on load, and always right around when it shifts (before and/or after). At WOT it is loud as heck. It happens when going uphill and downhill too. And I still can't hear a peep at idle or revving in park.

I'd think bearings but it squeaks a bit when shifting even while going down a steep slope at verrrrrrryyyyyy slow speed... I can't imagine that that would lift the front end enough to cause it?

Are there ANY pulleys that might do it when the tension on the belt changes that would NOT occur while in park?

1 FMF

iTrader: (1)

it's free & fairly easy to remove the serpentine belt.
if you have a good battery and it's not hot out and the engine is a reasonably cool temperature, you can remove the serp belt and go drive for a few minutes to see if the squeak is still there. if you want to be thorough, don't forget the belt on the AC compressor and make sure your heat/ac is turned off.

big_g

I thought of that, but I live in Arizona and it was 95 today...
It does sound like it is towards the drivers side, though its hard to tell if that is just because that is the side I'm driving on...

wssix99

iTrader: (5)

That doesn't matter because your water pump won't be on to push anything to the radiator, which is the only thing that will really care what temperature it is outside.

You have enough time to drive the car for it to heat up from 95 degrees to 180. If it was 70 degrees outside, you'd just get a very small amount of time to drive it - but you should be able to do what you need to do.

LS6427

iTrader: (2)

If you still have A/C in the car:

Remove your A/C belt....go for a drive and see if the squeak is gone when you go WOT. Could be your compressor or one of those pulleys making the noise.

You could also remove the serpentine belt and A/C belt completely and go for a quick test.....NO you will not over heat if you do it quickly with a completely cold engine. Rule out the belt.

.

Majestic9C1

iTrader: (19)

take off the belt and spin the pulleys... If one or a few just spin and spin and spin.. or hardly spins at all (less than a full rotation) then they are bad.

jaxcam02

iTrader: (1)

maybe try to regrease your pulleys with waterproof bearing grease. I cleaned mine up real good with a degreaser. Rinsed with distilled water and then packed in some new grease with a toothpick

big_g

The plot thickens... I was taking another close look at the belt/pulleys and I noticed what appears to be a slight "vibration or wobble" in my crank pulley during idle. I crawled underneath while it was idling and yeah it is definitely vibrating (seems like it might be making a ticking noise too?). Should it not be moving at all? (I'm a noob in this area...sorry)

And might this be why I only get noise while actually driving the car, and generally only when at the top/bottom of gears?

Have I screwed up my car driving it with this issue for months, thinking it was just a small belt issue? The car runs fine except for the squeaking noise, as well as some possible power loss at lower RPMs.

wssix99

iTrader: (5)

This shouldn't be it. If anything on the engine were the problem, it would squeal at idle when you rev the engine. The rotating accessories on the front don't know the difference between a car in motion and a car at idle. Only the internal bearings, etc. would see different forces when they get loaded up, but if you had a problem there - I would expect your engine would have blown up by now.

My guess is that you have two sources of squeal:
- One belt/pulley related that expresses when you "punch it".
- One drive train related when you are moving at speed.