Screeching 320i

Post Tue May 28, 2013 4:35 pm

Hi,

I have a 320i that develops a very loud screeching noise (assume belts) when first starting, pulling away, decelerating/changing down. By all accounts belt tensioner is as tight as it will go and belts are new.

Looking retro cool in my Cabrio is spoilt by sounding like a flock of angry parrots. Thoughts welcomed.

Cheers

C

Post Tue May 28, 2013 4:42 pm

If it's not the belts but it's definitely the engine, next check would be the water pump. It should turn freely by hand, so if it's graunchy or stiff then it needs replacing.

Post Tue May 28, 2013 8:58 pm

Examine the pulleys where the belt runs. The section polished by the belt should not go right to the bottom of the grooves in the pulleys. If it does, the belt will slip, however tight it is.

Post Tue May 28, 2013 9:08 pm

Also check the bracket that tightens the belts, I have in the past replaced around 3 power steering tensioner brackets on 3 different E30s as the teeth have worn away, not letting it actually tighten up any more.

Post Tue May 28, 2013 10:40 pm

Thanks for the feedback, a bit to be getting on with!

Post Tue May 28, 2013 11:05 pm

Jim320i wrote:......around 3 power steering tensioner brackets on 3 different E30s as the teeth have worn away

This happens when the nut securing the tensioner pinion is slackened off too much when adjusting the tension, allowing the pinion to slide off the side of the teeth of the rack. The nut should only be slackened enough too let the pinion turn easily.
Applies to the similar alternator tensioner as well.