2008 XC90 v8 - rattle noise at idle - serpentine tensioner? water pump? Topic is solved

mlotek511 · Post by **mlotek511** » 08 Apr 2019, 18:56

Most noticeable at idle - it can best be heard at about 17 seconds into the video, sorry for the poor video:

Anyone have a similar noise? I tried looking on the forums/youtube but none were close to the sound I have. I was thinking starting cheap with replacing serp belt tensioners and pulleys? Or could it be possibly the water pump / power steering pump?

Thanks
Tom

Masscomguru · Post by **Masscomguru** » 08 Apr 2019, 19:22

Have you had the idler pulleys replaced? If not, I would not run that engine until you do. When those go it’s a bad day.

mlotek511 · Post by **mlotek511** » 08 Apr 2019, 19:39

I have not - not sure if the previous owner did (assuming not). I was going to order:

Volvo Drive Belt Idler Pulley - 31216198 - Qty. 2
Volvo Automatic Belt Tensioner Assembly - 31216199 - Qty. 1 (Comes with Tension Holder In-Place)
Volvo Serpentine Belt - 8653617 - Qty. 1

So this is probably it?

Thanks,
Tom

mlotek511 · Post by **mlotek511** » 08 Apr 2019, 20:09

Ordered, will change out and report back.

Post by **jimmy57** » 08 Apr 2019, 20:48

The tensioner is damped. Even though it has the lock on it you will have to move it to get the lock off. The dampening is pretty strong so you put a 6 point socket on the hex nub and push on it and wait for it to s l o w l y move. A lot of these tensioners get that 19mm hex nub broken off due to expecting it to move immediately when you push on the breaker bar with socket.

mlotek511 · Post by **mlotek511** » 13 Apr 2019, 18:34

Replaced both pulleys and tensioner - sound is gone. Once I removed the pulleys and spun them in my hand it was obvious they were bad. FYI I am at 110k miles.

Thanks
Tom