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Noisy belt?

Posted: Wed Nov 30, 2011 5:35 pm
by Mk2_phil
Hello, need a bit of help trouble-shooting to be honest.

Had the alternator belt snap on me the other week, so I had a nice 5 mile tow back from my aging grandfather at breakneck speed! (Genuinely was one of the scariest moments in my life haha)

So I promptly changed the belt. In the process of doing this I noticed the timing belt was well past overdue as it was cracked all over! So I avoided driving the car and had the belt and tensioner changed. Took the car out and it was 3/4 up the temp gauge and I was concerned. As well as this, is was making a dull whining noise that it definitely wasn't previously to the snapped belt.I looked at the belts and noticed the alternator belt was under-tightened , so this was corrected - 1cm deflection. I also noticed that the timing belt wouldn't properly twist through the 90° it is meant too; maybe 3/4 of the twist. Which leads me to believe that the tensioner has been set too tight. Could this be responsible for my whining??

Also, the CRANKSHAFT pulley, this one------> Image

seems to be 'wobbling' when engine is running. Does this have any significance?


Is it a case of re-tensioning the tensioner, new tensioner, new pulley, all of the above??

Also worth noting is that since I adjusted the tension on the alternator belt it runs a lot less hot, only just past halfway. And since the alternator belt and timing belt have been changed I've done less than 50 miles.

Any help would be great, cheers guys in advance!

Phil

Re: Noisy belt?

Posted: Wed Nov 30, 2011 6:36 pm
by Risocco
Hey dude, a timing belt fitted too tight will whine and sound like a supercharger. Slacken it off and try again :good:

Re: Noisy belt?

Posted: Wed Nov 30, 2011 6:59 pm
by Mk2_phil
Hey man,

Yep, deffo sounds like a supercharger.
How do you slacken it? Will it effect the timing/piston positions etc?

Re: Noisy belt?

Posted: Wed Nov 30, 2011 7:15 pm
by Risocco
It could affect the timing, depends if you disturb one or more of the sprockets. If your unsure, take it to a garage, its a 15 minute job mate :good:

Re: Noisy belt?

Posted: Thu Dec 01, 2011 12:31 am
by Mk2_phil
Thanks for the help, I'll keep you posted. :ok:

Re: Noisy belt?

Posted: Sun Dec 04, 2011 12:01 pm
by james butler
i had a wobbly pulley, the inside of the pulley had cracked which will cause your belt to slip + will get worse as you tighten it. i got a new one from vw was under 30 quid or try and get lucky down the scrapyard but i will warn you they are different shapes and sizes and will effect the running of other components suuch as water pump and alternator.
has anybody on here convberted to a sepentine belt? is it possible and if it is how do you do it?

Re: Noisy belt?

Posted: Thu Dec 08, 2011 1:53 pm
by Mk2_phil
Big thanks to Risocco, I loosened the tensioner and this solved my whining problem.

James, I'm going to keep an eye on the pulley in the next week and see if the correct tension makes all the difference, If not looks like a trip to the internet is required for new parts!