850 T5R serpentine belt and noises

**Andy G** · Tuesday 28th October 2014, 07:58

Right, I did a bit of searching but couldn't locate what I was after.

The 'engine' makes a loud screeching noise (or a constant high pitch grumbling noise) when running regardless of revs used and we have been told that if the belt (serpentine?) is released or tension removed the noise stops. So when we come to remove the belt, how hard is it to replace all the ancillaries this feeds? I was looking at the idler pulley, PAS pump and alternator. The car has done over 300k so we'll be having the timing belt done as one of the first things anyway. We'll not do that but entrust this to someone that knows what they're doing.

If this was done, I take it the serpentine belt has to come off anyhow, so it would be worth making sure the car was mechanically sound first before anything else is done.

**p fandango** · Tuesday 28th October 2014, 08:13

if you've got aircon the pump for that also runs off the same pump. Mine is totally different now so can't remember how they remove sorry

**Andy G** · Tuesday 28th October 2014, 08:30

thanks for that, yes it has a/c and is a 94 model (I think) so the number shown, is that the part number?

**merc85** · Tuesday 28th October 2014, 16:27

http://www.gatesautocat.com/drive/VO...93_10-96/36597

Note engine number, and maual or auto

**Saaamon** · Tuesday 28th October 2014, 16:42

I'd say its probably the air-con pump making that noise but could be wrong, the tensioner is easy to replace and you can get them from volvo, i'd replace this regardless of condition. As for all the rest, it is abit of a job if you were to do it yourself. Merc85 sorted me out a brand new alternator and so far its been spot on and we do a few miles in our yoke.

**Andy G** · Tuesday 28th October 2014, 18:03

many thanks, I'll double check the engine number. It's an auto.

I also think you're right regards replaceing what you can, might as well if its all coming apart.

The aircon doesn't work, it did but doesn't now so that could be the culprit, well I'm hoping it is

**oblark** · Tuesday 28th October 2014, 18:32

I`d put money on it being the idler wheel on the tensioner or the plastic idler wheel.

**hemihusky** · Tuesday 28th October 2014, 19:53

i had a similar noise problem with mine and the screeching part turned out to be the idler on the tentioner being completely shot. the low grumbling i had on mine on occasion and after doing a timing belt change the noise seems to have gone. but i cant be sure as it was a very intermittent fault to begin with! is your noise like this? (Was recorded per-timing belt and tentioner change)

https://www.dropbox.com/s/0onbb7p9tc...00920.mp4?dl=0

JT · Tuesday 28th October 2014, 20:53

If the AC is not working, I'd say it was the pump trying to work without
the gas in it.......

At least that's what mine did

**stribo** · Tuesday 28th October 2014, 21:20

Originally Posted by JT

If the AC is not working, I'd say it was the pump trying to work without
the gas in it.......

At least that's what mine did

If there's not gas in the system, the compressor shouldn't kick in, it'll just spin the pulley.

**Saaamon** · Tuesday 28th October 2014, 23:28

Originally Posted by Andy G

many thanks, I'll double check the engine number. It's an auto.

I also think you're right regards replaceing what you can, might as well if its all coming apart.

The aircon doesn't work, it did but doesn't now so that could be the culprit, well I'm hoping it is

If the noise is the a/c pump it will only be a worn bearing, that wouldn't cause it to stop working.

If the ALT, PAS and A/C are all good, i'd just replace the idler, tensioner and belt with new genuine items and it will be spot on.

**jamesy12345** · Tuesday 28th October 2014, 23:34

Maybe you could post a video with the noise.....have you used a genuine oil filter...

**kyboy** · Tuesday 28th October 2014, 23:52

I took my ac off and couldn't believe how much quieter mine was after!

**Andy G** · Thursday 30th October 2014, 19:42

cheers for the replies all, when its home I'll get a video shot, I haven't got the car with me.

**Andy G** · Tuesday 4th November 2014, 14:07

Hemi, that's exactly what it sounds like, I have a video so will post it up shortly.

**hemihusky** · Tuesday 4th November 2014, 14:20

Well on my case it was the serpentine belt idler. Does yours stop when the car warms up as mine did.

**Andy G** · Tuesday 4th November 2014, 16:06

no the noise is constant on mine regardless of temp.

**hemihusky** · Tuesday 4th November 2014, 17:03

i have one of those serpentine belt tools to make getting it off easy if you want to borrow it if you dont have one as i cant drive that far to you sadly (completely broke) but if its pretty close to my noise id say idler pulley as mine was absolutely shot