12 replies to this topic

[Svenska]

RE: my 1996 850 GLT. Obviously I can't reproduce a sound on the forum, but I'll say it's a whining sound that gets louder upon acceleration. It's definitely from the passenger-side front area of the engine compartment. As soon as the engine is started, it begins as a very audible, continuous, low-pitched whine. As you accelerate, it gets louder and faster-sounding, getting louder and faster with correlating engine load. It never goes away. I've had it for over a year now and cannot figure out what it is. I have removed the serpentine belt and then started the engine, the sound disappears. I know then it's not the water pump nor pulleys in the timing belt area nor something odd in the crankshaft pulley area. I have replaced the following (not to throw parts at this problem, but to actually replace failed items in this serpentine belt path):
alternator
plastic idler pulley (was actually getting rough/crunchy when turning by hand)
p/s pump
air pump (not in belt's path but a noisemaker)
serpentine belt itself

There even was a TSB I performed about a whine coming from the driver's side half-shaft upon acceleration that required a counterweight. That solved nothing. The noise persists. I have removed the belt and spun the tensioner pulley and the A/C pulley, both spin freely numerous revolutions and without any grinding feeling or resistance. I know now that it's not a drivetrain issue since this occurs at idle too. If you stood over the passenger front wheel area while the engine were running, you'd swear the sound was coming from the p/s pump - it's not. I've even tried a mechanic's stethoscope to locate the problem, almost impossible to pinpoint the area with those.

Has this ever happened to anyone?

[r850glt]

Does any of your pulleys on the idlers or rollers have a wobble when you shake them side to side ?

[CarVolvo]

Does any of your pulleys on the idlers or rollers have a wobble when you shake them side to side ?

you said you replaced the alternator and ps pump.. were these rebuilds?

Sometimes these wont make a noise until your at higher speeds.

But sounds like you have done a lot .. Have you taken a peek on your timing belt and assembly just in case?

[Svenska]

No, none of the pulleys wobble-they're perfectly straight.

The alternator was a rebuild (meaning a different one than the one I sent in), but the p/s pump is brand new. Keep in mind this noise is present at idle - less than 1,000 r.p.m. a hum or a whine that gets louder with engine load. I looked again today at the timing belt/water pump/pulleys. Nothing unusual there. This sound disappears when the main serpentine belt is disconnected, so I know it's located somewhere in those parts.

[blood_donor]

No, none of the pulleys wobble-they're perfectly straight.

The alternator was a rebuild (meaning a different one than the one I sent in), but the p/s pump is brand new. Keep in mind this noise is present at idle - less than 1,000 r.p.m. a hum or a whine that gets louder with engine load. I looked again today at the timing belt/water pump/pulleys. Nothing unusual there. This sound disappears when the main serpentine belt is disconnected, so I know it's located somewhere in those parts.

Stupid question--are you low on PS fluid? My rack sprung a leak, and every few days I would get a loud whine, which would go away when I poured some power steering fluid in the reservoir. I hope you don't need a new steering rack!

[CarVolvo]

Stupid question--are you low on PS fluid? My rack sprung a leak, and every few days I would get a loud whine, which would go away when I poured some power steering fluid in the reservoir. I hope you don't need a new steering rack!

What about the tensioner..that can make a sound as the bearings wear out.

[Svenska]

The p/s fluid level has always been fine, no leaks at all. I spun the tensioner pulley with the belt off and it was silent and felt completely normal.

[troyhyde]

Ditch the stethoscope and get a length of rubber hose (vac. tubing works well). Stick one side in your ear and scan around the engine with the other side. In my experience, this works much better than a stethoscope.

I'd pay attention to the serpentine idler pulley. These seem to howl some since they have plastic fins that create wind resistance. They are not necessarily defective, just noisy.

[laird]

The p/s fluid level has always been fine, no leaks at all. I spun the tensioner pulley with the belt off and it was silent and felt completely normal.

The tensioner may feel fine with no load but may in fact be the culprit.

[Svenska]

The serpentine idler is new - not the problem. The best way I can describe this noise is the way the old Volkswagen Beetles or vans sounded (or even some cars today) when you put them into reverse and back up at about 5 mph, that distinctive whining sound is exactly what this sounds like. I will try swapping out the belt tensioner with one from a friend's 850 though, I didn't think of that making this sound, but it may under load.

[Sinbad]

+1 to the vac tubing idea.... Just don't get it caught anywhere

[matt b]

My air pump whines a lot on colder, wet mornings. Don't know if yours has one or not, but it sounds bad, until the car is warmed up.

The tensioner may feel fine with no load but may in fact be the culprit.

I just had the timing belt done and the belt tensioners were replaced: neither wobbled, but both felt like they had bad bearings in them. A timing belt is $30, don't remember how much those things cost, but it was well worth it.