Volvo RWD 900 Forum

Hi
I've got a 3.0 6 cylinder auto dating back to 1995.
I've been getting an intermittent squeal from around the top/front of the engine. Usually just after starting for 5 mins or so then it goes away. The pitch of the squeal changes as I rev it. I have experienced this noise on other cars with loose belts but mine are OK. I also had a mechanic check the timing belt. He took the cover off and checked everything and says its not that.
Then I thought, noisy water pump, maybe?
Thoughts?
Thanks
Pete

The FAQ's have detailed instructions for R & R of the TIming Belt on the B6304.

DEWFPO
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1998 S90 083,228 and 1995 964 154,100

Dear crazypierre,

May this find you well. Based on replies to your post - and my reading of many posts over several years - I'd have the car towed to a mechanic, and have the timing belt, tensioner, and idler pully replaced. The reason: if the timing belt snaps, you're looking at a $2,500-3,000 head replacement, and possibly an engine replacement. Valves have been known to punch holes in pistons, when the timing belt fails.

Whatever is the cost of a tow (flat-bed truck is best), it is small compared with these monster outlays.

If you're at the point where the timing belt is due for a change, and it is making noise, get it done. NOW!!! Don't drive even half a block. Call a tow truck!!!!

Hope this helps.

Yours faithfully,

Spook

Hi
Thanks to all of you who've replied. I am now considering changing the timing belt, hydraulic tensioner and tensioning pullies myself. (And the serpentine belt and water pump while I'm at it.) I am pretty handy and once replaced the piston rings, valve seals and main bearings on my 1971 MG Midget, so I think I should be able to handle this job.
A lot has been written about aligning timing marks on the camshafts/crankshaft.
This may be a dumb question but:
If you don't turn the engine over after you've removed the timing belt, and put the new one on with the camshafts and crankshaft not having moved from the original positions, then there should be no need to re-align the camshafts/crankshafts again-right?
Or am I missing something?

Pete

Right......As long as one of the cams does not move when the old belt comes off, sometimes depending where the engine happened to stop a cam can move on its own because of valve spring tension. Be sure to mark the position of the cams with whiteout or something before removal of the belt. The crank is not going to move unless you move it.

After slipping on the new belt and slipping on the new one why not just check the alignment. It is not at all difficult to align with the marks, you just need a good eye to find the crank mark. In any event it is advised to turn the engine over by hand at least 2 revs before starting. This is to be sure that you do not have a gross error that would cause an interference event to occur.
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David Hunter

Thanks Guys. As usual, its reassuring to know you are always there to provide guidance before I start a job. The good thing is my 960 is "spare" right now so I'm not using it at the moment which means I can take my time on this.

One more questions if I may:
I have read elsewhere that its best to remove the front wheels and the skid plate to replace the belt. Is it really necessary to have access from the underneath or can I do everything from above?

Pete

You will need to get under the engine to remove a guard under the crank pulley. Cannot imagine why you would take of the wheels. I just drive er up on my ramps.
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David Hunter

I guess in theory one could just swap out the belt without placing everything on their marks. But would caution against that for two reasons that I can think of, one since the cams are under spring pressure who is to say a cam doesn't turn a bit while you are not looking at it. And if it did actually move, then you would have even more difficulty finding the factory marks without a timing belt in place. The other is the old belt will have stretched, not much, a couple of mm's maybe, so you could put a new belt on and move a pulley a little to for a tight fit and be moving it away from actual mark. It would be well worth the effort to find the marks on all three timing pulleys.

DanR '94 964 343,000 miles (109,000 on the new engine)
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DanR

Dear Pete,

May this find you well. I don't have a 960, so have never done a timing belt change. However, I've done a timing belt change on a 760 (with a B230F, non-interference engine), on which the belt had not broken. In that situation, if nothing is moved, one can simply put on the new belt.

Even so, it is well to mark the positions of the crankshaft and camshaft pulleys, before removing the belt. If the metal is cleaned with a solvent, white-out can be used. Then, take a photo, as a back-up (in case one of the marks gets rubbed-off).

I think the Board's bona-fide 960 experts should provide specific guidance: too much is at stake in this work.

Yours faithfully,

Spook

What I have done to isolate a belt squeal is to take off the serpentine belt and start the engine. If it continues, then the timing belt hardware is at fault, if it stops then it is the serpentine belt hardware or an accessory item. Your serpentine belt tensioner could be letting it slip a little, a new belt might quiet it for short time.

I have replace my serpentine idler pulley about every three years do to faulty/tired bearings.

DanR '94 964 343,000 miles (109,000 on the new engine)
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DanR

You better have another word with that mechanic. A timing belt cannot squeal no matter how worn so what was he really checking? The tensioner and idler pulleys for the timing belt however can squeal just as you described. If either one is getting ready to seize your belt is toast and so is the engine. The recommendation is to replace those pulleys and maybe even the water pump every other belt change. When is the belt due?


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David Hunter

Hi David
In fairness to the mechanic, I did ask him to check the timing belt-he didn't suggest that might be the problem. You're right of course-thinking about it, there is no way that toothed belt would squeal. What was I thinking!
It is due to be changed in about 10K miles. Last done at 81K and now on 150K.
Of course, you're probably right-best to be safe than sorry.
Pete

The interval is 70K, you are due now. It is recommended to change the idler and tensioner pulley every other belt change because they do fail. It sounds as if one of your pulleys is ready to seize up, if it does your engine is an interference engine and will be toast.

I had a similar scenario on my V90, brief sqeaking when cold then after a few weeks of this I had failure of the idler bearing, belt came off, 19 bent valves. I would have the work done immediately.
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David Hunter

Pete,

When my 95 did this very thing it was an idler pulley for the serpentine belt. Take the serpentine belt off and start the engine cold and see if the noise is gone.

DEWFPO
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1998 S90 083,228 and 1995 964 154,100

Among the other ideas, to see if it a belt squealing you can spray belt dressing or even water to stop or change the pitch. Belt dressing is not a fix for a belt. If it is a belt it is loose, hardened (old) or glazed.
\
Tom

make absolutely SURE the tensioners in the timing belt circuit are still internally lubricated and spinning freely. i have seen them wear and cause the t belt to break disintegrating the upper end of the engine. the belt only broke because the tensioners failed. make sure the mechanic who verified the belt was good also verified the tensioners were good as well.

something hard to do unless you release the tension on the belt allowing the tensioners to spin freely and listen.

The crank pulley may be slipping; it has an inner layer of rubber that can deteriorate over time (as mine did last year). Take a paint marker and draw a line across the front of the crank pulley, and after you have taken a drive, see if half of the pulley has slipped, moving the painted line.

Ari