E90 320D Belt Tensioner noise

[F2004M]

Hi,

I've got a really irritating speak which appears to be the tensioner on an 06 E90 320D.

It squeals then seems to warm up and slowly die down, but if you spray the belt with anything the noise goes away and the engine sounds fine.

I've had a mechanic who lives local take a quick look at it and he says the belt appears new and there's no play with the pulley.
He used a brush on it and again the sound/squeal went away for a day or two.

Any ideas?

I may just bite the bullet and buy an official BMW rather than a 3rd part belt.

Cheers

[Riggie]

I had this on my X5 with the serpentine belt tensioner. There are 2 of them and the way I identified the culprit was by spraying WD40 using the long straw on the can, directly into the front of the tensioner. The noisy one quietened immediately.

[E-bmw]

I wouldn't use wd40, but I have 100% successfully used this method with a garden type water spray to help identify whether it is a belt/pulley/bearing causing the noise before.

Be as precise as you can be & as soon as you hit the culprit the noise goes for a few seconds.

[helix402]

F2004M said:

Hi,

I've got a really irritating speak which appears to be the tensioner on an 06 E90 320D.

It squeals then seems to warm up and slowly die down, but if you spray the belt with anything the noise goes away and the engine sounds fine.

I've had a mechanic who lives local take a quick look at it and he says the belt appears new and there's no play with the pulley.
He used a brush on it and again the sound/squeal went away for a day or two.

Any ideas?

I may just bite the bullet and buy an official BMW rather than a 3rd part belt.

Cheers

No need to go to BMW for the belt. They don't make them, just go for a good one such as Continental/Gates etc. BMW usually sell a kit with pulleys and belt though if you do want to stick with gen. Gates also do kits.

[F2004M]

Riggie said:

I had this on my X5 with the serpentine belt tensioner. There are 2 of them and the way I identified the culprit was by spraying WD40 using the long straw on the can, directly into the front of the tensioner. The noisy one quietened immediately.

Half tempted to try this, but I did buy some belt tensioner spray from ebay and after a tiny spray the noise went away and came back maybe 4 days later?!

I'm amazing only a small amount of spray kills the noise.

Has the noise stopped completely?

[E-bmw]

I suspect with him saying "the way I identified the culprit was by spraying it with wd40" the answer is no.