Screeching noise help!!

[Porkchop]

Haven't been on the forums for a bit but that usually means all is well with my 1984 240 GL Estate. Anyway, long story short, I've been chasing a loud screeching noise emanating from the front of the car that has been getting louder and more persistent over the last few months. I've put new (matched) belts on the alternator/water pump and also replaced the steering pump one as well, zero difference much to my surprise. I deglazed the pulleys, checked and adjusted their alignment etc, zero result again.

I then discovered that both my engine mounts were knackered after attempting an oil change and realising that the oil filter was sitting on the RH one, a cow of a job as a consequence of both mounts being sheared off but finished it today. I naively thought this might have been the missing part in the puzzle but after a test run the noise is still there and now I'm starting to pull my hair out! Can any members shed some light on what to look for next? cheers, Porkchop

[Paul240480]

Guess you have 9mm Volvo belts? Try 10mm, mine are Dayco make and solved my 'squeal'. After months of tightening and re-tightening my 9mm Volvo ones.

[Joe of Loath]

You might also need 11.3mm belts, that's what I needed to stop my engine squealing.

[Porkchop]

Ok, I'm delving back into the archives to work out which belts and the measurements, the 9.5 x 925 were the original ones I took off (genuine Volvo) and the matched pair to replace are Contitech 10 x 925, the supplier said the genuine Volvo ones are unavailable (this is Australia btw). I had bought a couple of belts which were 11mm wide but didn't fit them as they weren't matched and were quite a bit wider than the original. I guess what you're saying is that as the pulleys are presumably worn the wider belt sits higher and that influences the "squeal" factor? The PS pump belt was a genuine nearly-new 9.5 that I had kicking around in my toolbox, this seems to sit quite deeply in the groove of the pulley which I suppose is normal?

[Clifford Pope]

Have you tried briefly running the engine with the belts off?
Try removing the steering one first, then the other two. Then at least you have pinpointed the probable source.
Does the water pump itself feel OK when you spin it by hand?
Alternator OK - bearing or brushes?

try a squirt of WD40 while watching it - any change anywhere?

[tannachyallen]

My steering pump bracket was slightly loose and caused the belts to squeal badly until I realigned and tightened it.

Dave A.

[Stephen Edwin]

PorkChop - have you tried adding a water pump lubricant to the cooling system? "In the olde days" that additive was cheap and readily available and it might still be available now.

[CaptainAhab]

WD40 down the back of the alternator pulley!

[honestjoe]

All good suggestions..try pouring just water on to the affected belts/ pulleys..if even just to change the character of the screech...hj.

[Porkchop]

Originally Posted by Clifford Pope

Have you tried briefly running the engine with the belts off?
Try removing the steering one first, then the other two. Then at least you have pinpointed the probable source.
Does the water pump itself feel OK when you spin it by hand?
Alternator OK - bearing or brushes?

try a squirt of WD40 while watching it - any change anywhere?

Thanks Clifford, I'll try the isolation method once I've had breakfast. I replaced the brushes in the alternator myself a few months ago as it was starting to fail and had the local auto electrician do the rest of the work as I couldn't source the correct bearings hoping that it might have been the source of the noise but again after reassembly zero result/change.
I haven't checked out the water pump but am intending to do a timing belt change asap as it's interval has come around. I've got a good quality Hepu pump sitting around ready to fit including new seals plus new oil seals (haven't done a timing belt before so slightly nervous!)

I wonder if the rear bush in the alternator could be dry although I seem to remember giving it a fill with WD40 whilst on the bench.

Will report back....