VS V6 serpentine belt keeps slipping?

[Jeff Owens]

Can anyone please advise me why the serpenting belt on my VS V6 keeps shifting?

You can see the belt has moved on the crankshaft pulley. Would it be caused by a stuffed tensioner assembly, or crankshaft pulley? The car has 200,000 km on it. Thanks heaps.

[WAFFEN SS]

Id say you pully bearings are gone on the tensioner and idler. The belt would be buggered now too from that.

[Jeff Owens]

I failed to mention that I replaced the tensioner pulley about 12 months ago because it was starting to become noisy. Is it very difficult to replace the tensioner assembly? Also, is likely that the harmonic balancer would need replacing give the vehicles mileage (200K) ?

[hako]

I wouldn't replace anything till it gave real signs of failing as the tensioner assy costs a bit and also ain't easy to replace - same goes for harmonic balancer. The belt can change position from time to time sometimes for no apparent reason although it will only be a mm or two but just to make sure I'd remove the serpentine belt and spin each pulley and check for side play. Pay careful attention to the water pump pulley as any roughness can indicate the bearing starting to fail.

[Jeff Owens]

Thanks very much Hako!

[wortus]

Jeff. I'd be removing the serpentine belt and checking the bearings in the water pump and alternator by turning them by hand and feeling for any roughness or noise. Also check that all the pulleys are in line with each other especially the power steering pump pulley.

[Jeff Owens]

Thanks Wortus! I have just done what you suggested and the water pump and alternator appear to be running smoothly. The upper idler pulley is a bit rough, could this be the problem?
Mate, sorry if i sound dumb but how do I check that the pulleys are in line with each other?

[QuickVRII95]

If You Still Have The Original Plastic Crap Tensioners... Replace Them With Metal Ones... It Sounds To Me, Like Their Worn On One Side Of The Pulley.. (It Happens When You Floor It & The Plastic Heats Up In The Spot Where You Gun It)

[hako]

Thanks Wortus! I have just done what you suggested and the water pump and alternator appear to be running smoothly. The upper idler pulley is a bit rough, could this be the problem?
Mate, sorry if i sound dumb but how do I check that the pulleys are in line with each other?

All you can really do is eyeball along the side of the serpentine belt with the engine off. They should all line up. You could also closely inspect the ribs on the belt to see if they are wearing on one side.
Maybe also have a close look at how the actual bearings sit in the pulleys - maybe one has shifted.....also check the bolts that hold the power steering pulley on as they have been known to come loose.

[Benboy]

Also, is likely that the harmonic balancer would need replacing give the vehicles mileage (200K) ?

If the Harmonic Balancer is beginning to fail you will likely hear a loud (very loud) banging noise coming from the vicinity of the engine. Usually means that the rubber moulding in the balancer is/has cracked/broken and requires immediate replacement. Once you have heard a failing HB you will never forget it.

[Jeff Owens]

After replacing both idler pulleys and the tensioner pulley, the serpentine belt is still slipping. The belt is slipping down on the harmonic balancer and creates the same sensation if you were driving in a too higher gear. I'm stuffed to know what to do next.

[hako]

Can you explain it in more detail please - I cannot see how the belt can slip down on the harmonic balancer....maybe take a pix. When you say 'slip', do you mean it actually jumps one of the ridges?

[Jeff Owens]

Thanks Hako, yeah I mean the belt is jumping ridges on the harmonic balancer causing it to move in the direction of the radiator.

[RX25SE]

Just to be 100% clear, have you replaced the tensioner arm assembly. The spring loaded one?

[hako]

I'd check the A/C pulley as that's the pulley immediately ahead of the HB - if it's out, it will move the belt on the HB. Otherwise I cannot figure how this is happening. From memory, the belt goes from the A/C to the HB and then the PS.....so maybe check the PS pulleys well. Have you done anything to, or touched, either the PS or A/C pulleys?

[Brett_jjj]

The harmonic balancer is probably on its way out and is moving around a bit on the rubber that seperates the two parts of the balancer..

[ashzv6]

check the belt tension with your thumb,
i am having a similar issue, replaced thensior assembly and pulleys and it still squeled
now it comes and goes but is bearable, im thinking either waterpemp pully/bearing and alt.
My belt isnt moving away from the balancer like you say.

[Jeff Owens]

RX25SE: I have only replaced the bearing on the tensioner assembly.

Hako: I haven't touched the AC pulley at any stage but did have a reconditioned power steering pump fitted at the start of the year.

Brett JJJ: I'm thinking that maybe I should just replace the harmonic balancer as the car has over 200,00 k s on it.

Thanks guys for the advice.

[rosscos stateo]

Hey mate, Check your belt is routed properly. I did the mother in laws pulleys once and put a new belt on. When I started it up it was slipping. While it looked like I put it on right, I went aroung the idler and power steering wrong.
Can you move the balancer with a screw driver back and forth? Is the belt chewing out on one side.
Another theory is check the belt for metal flakes in the ridges, we had a cummins engine that was losing the hardening off the balancer and the metal was sticking in the belt. So basically metal on metal and it slipped after a certain rev range. Done a few kays by then but.

[RX25SE]

RX25SE: I have only replaced the bearing on the tensioner assembly.

I would replace the tensioner.
You need to drain the coolant (do a flush while your at it) to remove the heater pipe. Fit a new O ring (genuine) before you put it back on.

[hako]

Unless the HB has signs of the rubber splitting or runs with a wobble I wouldn't just replace it. You say you fitted a new PS pump earlier this year - the bolts on the pulley can come loose...not sure if they have a spacer as well but maybe eyeball whether it's in line. Some of the above posts have good tips like the belt not on the pulleys in the correct order.

[bluecar]

Good morning

Call me lazy for asking this, but to remove the idler do you just undo the bolt in the centre (of the idler) turning in the normal direction?

[klampy]

Good morning

Call me lazy for asking this, but to remove the idler do you just undo the bolt in the centre (of the idler) turning in the normal direction?

no its a reverse thread.


i have a VX that the belt slipped off regularly, i just put on a new belt and it stopped slipping.

[bluecar]

no its a reverse thread.


i have a VX that the belt slipped off regularly, i just put on a new belt and it stopped slipping.

Thanks klampy. It's hungover more than lazy. Thinking was pretty slow earlier in the day. The cars in town at the moment. I'll have a go at it when it gets back.