Engine: 70: Auxiliary / Serpentine Belt Slipping Off

[BritInSweden]

Happy new year all! Have a V70 D5 2005, Euro 3 and auxiliary belt keeps slipping off to right side (drivers side) See pics. First time it happened the power steering died and battery warning light came on but was close to home to got it back. Checked pulleys etc and see no problems, everything moving smoothly no strange noises, no play on the wheels and luckily no damage to timing belt. Swapped out aux belt, idler pully and tensioner as it was due, thanks to Si Robb / Cheshired for his helpful video https://www.youtube.com/watch?v=DLyiYnUkQuE

But the belt moves itself immediately off the it's cogs to the right and eventually slips off.

The only thing I noticed which may or may not be an issue is the outside of the power steering compressor wheel moves when I push it with my fingers, the middle bit also moves as it should.

No warning lights but dare not run the engine for longer than a few seconds. Belt is tensioned and pretty taught but I am novice so can't be scientific about what taught means.

Any help is much appreciated as we've been without a car all Christmas and really need it fixed.

Thanks again in advance!
Nat

[reggit]

One of the pulleys must be skewed over to make it wander off the run.
I’d double check everything is straight, especially the one you suspect may have an issue. Couldn’t quite picture it from your description and I no longer have a P2 so can’t run out and have a look.

[oragex]

May also want to make sure the belt is the same length as the old one. There are two lengths for these belts, long one for the 110 bar pumps, short one for the 120bar pumps. But I would rather think as above, a problem wit ha pulley. The steering pulley should not have much axial play to it. Was the old belt running fine ?

[BritInSweden]

Thanks for answers! The old belt did slip off in exactly the same way so I swapped belt and tensioner / idler out and new parts all correct and old parts seem to have no problems either, bit annoying but needed to be done and got me out the house for a few hours

In the cold light of day today I spotted a couple of things and posted pics here. I am a proper but keen novice and trying to avoid the eye watering mechanic hourly rates up here in Sweden.

1. Oil and muck around the back of the power steering pulley wheel and back of unit which points to a leak. There's a bit of left/right play if I tug on the wheel, it spins a couple of inches on it's own but wouldn't say it spins freely, no noises and seems to be in line with other wheels and pulleys. Steering fluid low.

2. The crankshaft pulley (bottom) looks about 1 inch to the right of the other wheels and pulleys when I look straight down. In pic I used a straight edge to try to show it. Maybe this is normal otherwise that would pull the belt off to the right I guess?

Also checked alternator by putting screw driver in the check clutch and spins clockwise as it should no noises and spins ok. All wheels except crankshaft seem to be in line to my eye.

Thanks again for any insights and tips on doing the work myself.
Nat

[reggit]

That bottom pulley should be in line with the others or it will pull the belt off.
Unfortunately I’ve no idea as to the cause of it being offset.

Edit: wondering if the bottom pulley retaining bolt is loose, it should be very tight, allowing the pulley to come partially off. I’d check under the timing belt cover to check if the timing belt pulley is also misaligned.

[BritInSweden]

Quote:

"The only thing I noticed which may or may not be an issue is the outside of the power steering compressor wheel moves when I push it with my fingers, the middle bit also moves as it should."


EDIT: Sorry realised I meant the air conditioning compressor pulley not power steering compressor.

I read that these AC pulleys have some kind of clutch system so maybe that's why outer edge turns with my fingers pushing it as well as the inner groove which spins more freely?

[oragex]

The compressor has a pulley with clutch - the clutch indeed is the outer plate with 'springs', it's engaging only when turning the AC on and it starts spinning along with the pulley. Only test is the pulley itself spins by hand without much hissing. However, from your last pic, as reggit says the harmonic balancer (crank pulley) sits way off set compared to the other pulleys, was any work done on it ? I may simply just come off the center bolt, may worth a close look

[BritInSweden]

It was dark and raining last night when I tested the new aux belt and pulleys before it slipped off, as with the old one, so I threw some F words into it and gave up. I remember the belt looked a bit strange running at an angle right to left from the crank pulley to the idler (left) like the belt was trying to slide off the idler. From what I know now this isn''t right.

I will have a proper look at the crank pulley tomorrow and check the bolts.Could it be the bearings that have gone on it maybe and any idea on how to check for that?

The timing belt etc are all due to be changed so could be a good time to do that, if I have the guts to try that one. I've been warned it's a tricky one to get right.

Thanks again for the advice. Will report back tomorrow.

[BlueRubber]

Originally Posted by BritInSweden

Steering fluid low.

You should really top up the fluid, it takes 'ch11s' type fluid, very cheap to buy.
The fluid should be a green colour, it's red you will need to flush the system.

Hope you get the belt issue sorted.

[wynnj]

There's a very strong chance that the crankshaft pulley being out of line is your problem and should be addressed urgently.
I had an issue with one a few years ago; the outer (grooved) pulley is bonded to a hard rubber material which if I remember rightly is there to absorb some of the torque from the crankshaft. On mine the bonding failed and the outer pulley came off, luckily just as I arrived home and switched off the engine. I'd had a chirupping noise from that end of the engine for a while before this happened but hadn't been able to track it down. To check this for yourself you will probably be able to realign (i.e. slide it back into place) the bottom pulley on it's shock mount mount once the tension is off the sepentine auxilliaries belt.
The only answer is a replacement pulley which is not too expensive nor too difficult to do yourself provided you can undo the crank nut. I had great difficulty with mine and have since bought a 30mm 3/4" drive socket, extension bar and 1m long breaker bar, and support the extension bar on an axle stand set to the right height. At the time I had to resort to paying a mobile lorry tyre fitter to come out to me and use his pneumatic impact gun. If you live close to a garage with heavy duty equipment you might get away with driving it there to get it loosened (once you've realigned the pulley of course) or if there's a garage not too far away, leave off the auxilliaries belt and drive the car without it. There will be no battery charging of course nor power steering which will be very heavy at very low speeds but manageable once moving.
You'll need something pretty heavy duty to re-torque the nut up to 300nm (I think without checking) when it is replaced.
Whatever, don't drive without doing something as there are many report of the auxilliaries belt jamming the crank pulley if it comes off and then pushing the valves into the pistons, which on an old car would probably mean a writen off engine!
If it's due a cambelt change do that at the same time. It's not too difficult if you follow instructions. The biggest problem with changing the cambelt is removing the crankshaft nut!
Good luck and happy new year to all on this forum.