C70 S70 V70: Belt noise

[StatusRed]

A belt in the engine bay has been noisy since January and it gets worse as revs increase, it's getting annoying.. I changed the auxillary drive belt in September / October so I'd be annoyed if it needed replacing again.

It's in good condition visually, the video shows the timing belt but I think the noise is coming from the auxillary drive belt or a related pulley. Any ideas?

[YOUTUBE]https://www.youtube.com/watch?v=uSpA-trnXZw[/YOUTUBE]

[Clan]

Originally Posted by StatusRed

A belt in the engine bay has been noisy since January and it gets worse as revs increase, it's getting annoying.. I changed the auxillary drive belt in September / October so I'd be annoyed if it needed replacing again.

It's in good condition visually, the video shows the timing belt but I think the noise is coming from the auxillary drive belt or a related pulley. Any ideas?

[YOUTUBE]https://www.youtube.com/watch?v=uSpA-trnXZw[/YOUTUBE]

That sounds more like a semi seized cam belt idler wheel , i would not drive it or you could wreck the engine .

what is the history ? Neglected servicing , Non volvo parts ?

[StatusRed]

Originally Posted by Clan

That sounds more like a semi seized cam belt idler wheel , i would not drive it or you could wreck the engine .

what is the history ? Neglected servicing , Non volvo parts ?

It was sorned for 3 years before I got it, spent last summer getting it back on the road doing major service, flushing fluids etc.. There is a note in the handbook that the cam belt was changed at 77k miles, now on 102k miles.

It was just in at a Volvo specialist to get pothole repairs done, was making this noise then too but they didn't mention anything..

[StatusRed]

Also does it look like the cambelt is sitting right?

[tdidave]

I tend to agree with Clan re an idler. Also I've had a water-pump sound very similar to that. Not sure if you have a cambelt driven water-pump on this engine.

What you could do is spray a little water on the belts separately. This will often show up and isolate a belt if its squeaking.

The belt position on the sprockets looks fine.

Dave..

[ITSv40]

I agree with the above comments.

I would change the belt anyway as you have no idea what was actually changed previously and were Volvo/quality oem parts used or cheepo from the cheepest motor factors.

When changing the timing belt the belt adjuster and idler pulley should also be changed. It is also recommended that the auxillary belt and tensioner are changed at the same time, although you have already done these.

The water pump is driven by the timing belt; if it is an original Volvo pump and not showing any sign of leaks or wear I would leave well alone. The pumps are virtually bombproof - I have had one pump last 270,000mls and another 370,000mls and still in good condition. The pump on my current V40 has done 150,000mls again without any issues. If you do change the pump only fit a genuine Volvo one - they are about £100 or so from Volvo.

[StatusRed]

Originally Posted by ITSv40

I agree with the above comments.

I would change the belt anyway as you have no idea what was actually changed previously and were Volvo/quality oem parts used or cheepo from the cheepest motor factors.

When changing the timing belt the belt adjuster and idler pulley should also be changed. It is also recommended that the auxillary belt and tensioner are changed at the same time, although you have already done these.

The water pump is driven by the timing belt; if it is an original Volvo pump and not showing any sign of leaks or wear I would leave well alone. The pumps are virtually bombproof - I have had one pump last 270,000mls and another 370,000mls and still in good condition. The pump on my current V40 has done 150,000mls again without any issues. If you do change the pump only fit a genuine Volvo one - they are about £100 or so from Volvo.

Timing belt does say Volvo on it, FYI so I assume that's OEM.

I didn't change the auxillary belt's tensioner, just the belt.

Is it worth and OK to remove the auxillary drive belt and run the engine without the belt on for just a minute to see if the sound goes away? Or is this not a good idea.

[Volvofreak2]

Hej, you can do this, as Water and Oilpump are not driven by this belt, but be aware, that the batterie won't be charched at that time!

[ITSv40]

Originally Posted by StatusRed

Timing belt does say Volvo on it, FYI so I assume that's OEM.

I didn't change the auxillary belt's tensioner, just the belt.

Is it worth and OK to remove the auxillary drive belt and run the engine without the belt on for just a minute to see if the sound goes away? Or is this not a good idea.

Yes, remove the auxiliary belt and test to see if the noise has stopped or still there.

If it is coming from the timing belt, I would change the belt, tensioner and adjuster, as even though the belt has Volvo on it there is no guarantee that the idler pulley was also changed. When changing the auxiliary belt the adjuster should also be changed as generally it is the adjuster that collapses not the belt snapping.

[Luxobarge]

To save actually removing the aux belt, if you have a decent tool for releasing the tension on the tensioner arm (I made one out of a bit of square-section tube) then if you take care you may be able to simply release the tension while the engine is running, just enough to stop the belt from turning. If the noise stops then, at least you know it's something on the aux belt system and if not, it's probably something on the cam belt system, which makes fixing it much more urgent. Actually, either way I'd be very wary of using the car until you've at least diagnosed the problem.