Belt whine

[brian j 31]

Hi. 
my 1.9 has a definite whine from the belt area on my 1.9 at high revs

 

the cambelt, tensioner and water pump are new INA parts. The car has a spring tensioner and the belt has been heat cycled and re-tensioned. I can’t see how I could have got that wrong. (I have done a few now)

the alternator belt and aircon belt are new, and adjusted so there is a comfortable 90deg twist at the middle of the longest run. 
the aircon belt tensioner is new. The noise happens with the aircon on or off so it seems unlikely it’s the A/C pump or the electromagnetic clutch bearings, because pump on/off would change it. 
 

it is all good at low/medium revs, but after about 4500rpm there is a whine which is very noticeable in the car. 
 

in the absence of any obvious issue, I would love any pointers as to where to look…

 

[PhilNW 40]

Is the noise there if you run the engine with the alternator belt off?

 

I.e which belt is it?

[DamirGTI 327]

As above , dismantle all the accessory belts (alternator and AC) and then go for a short spin and see what happens .. could be worn/dried out alternator bearings getting noisy when the alternator heats up .

Also TB covers often tend to be noisy , bottom plastic ones from the belt rubbing on them , and especially top metal cover if not bolted correctly due to vibrations at certain rpm. or simply because there's not enough free space between the belt/pulley and cover . 

 

If having AC i presume you do not have hydraulic PAS pump ?

 

Was the noise there before TB kit replacement ?

 

I had an nasty surprise around year ago after TB replacement - i got brand new belt which was defective from factory !

 

The belt had what they call "lateral damage" , it wasn't cut straight from the roll and with the engine running (TB covers off) you could clearly see it rapidly wandering sideways from left to right on the pulleys/sprockets and pretty severe close to a point of sliding off from the pulleys and making an real mess .

 

Haven't checked if everything spins true after TB assembly as i was in a hurry so popped up all the covers back on and off you go ... but after a week or so driving it started to get noisy - water pump bearing suffered damage caused by that defective belt and it started making noise .

 

New parts can be defective straight from the box .. nowadays more so than back in time round 20years ago , quality and quality control simply isn't what it used to be .

 

One more thing , if over tensioned , TB will be noisy .. i know it's automatic tensioner via spring preload but check anyways cause of the above , you never know unless you check/inspect !

 

D

Edited April 28 by DamirGTI

[brian j 31]

@DamirGTI It still has a hydraulic PAS pump. 
It was fine with the old belts 8 years ago when I fitted them, but since then it was out of my ownership and laid up so I never really ran it before changing the belts again. 
I think you’re right, I need to take the accessory belts off and see what happens, and if the sound is still there check the timing belt. 

[DamirGTI 327]

I see .. could be PAS pump too then .

 

Worn pump shaft seal letting air into the system , or old degraded oil which would be easy fix by simply replacing it (it does heat up whilst driving and the pressure in the PAS system is very high , up to around 80 Bar depending on the model)

 

D