New belts, screeching

S

sconner0

Registered User
Joined
Jun 19, 2020
Messages
20
Reaction score
2
Points
3
Location
London
Basically sounds like this:



I've got both belts, and everything that goes with it replaced with an aftermarket parts (INA). It only does that on cold start, and not every time. I've tried previously spraying both belts inside and outside with WD40 which didn't help at first, but after the noise was gone for a whole month.

Where should I start my investigation? Try spraying WD-40 on pulleys bearings and see if the noise is going away?
 
Check the alternator or compressor pulleys as mine did this to ages until I swapped alternator out, haven't had it since, annoyed the **** out of me.
 
Try rubbing wax from a decent size candle as the belts are spinning, Inside and sides, this will stop belts from squealing and as above stay away from oil based stuff on rubber belts.
 
Personally, I would put that noise down to a bearing somewhere on the belt circuit - e.g. typically a tensioner or alternator. With the belt off it would be obvious when turning the bearings/pulleys in question my hand. They would either feel very rough or when slapped would spin like a loose, noisy roller skate. They should feel smooth and when slapped there should be some smooth resistance that stops them continually spinning.
 
Cool! Thanks guys, I'll check the pulleys first. And as a temporary fix wax from a candle should work just fine. I'll update when I get to it, probably tomorrow when it's a bit cooler outside and I have a day off.
 
I had a noisy belt on my mk 4 GTi 1.8T. Always audible at low revs. I swoppwd it for a Continental and no noise now.
 
It’s one of the bearings, spray each one with WD40, it does no harm.
Could also be the cam belt pulleys or water pump.
 
Found it!
86b3e054c69e4e7992d09b365c3caba3.jpg


Nr.2 Crankshaft belt pulley does it! Should I replace it? Or maybe it's wrongly tightened?
 
You're on the spot so to speak so if you say the problem is with the crank pulley - then I'll take your word for it. Usually these pulleys are "dampened" with rubber sandwiched between the centre section on the crank and the outer section holding the auxiliary belt. If that rubber filling breaks down, then you can get squeaks and vibration. No amount of spraying with WD40 or similar will make any difference and you will need to replace the pulley and central crank bolt.
 
  • Like
Reactions: sconner0
Awesome!

Basically I removed bottom cover and with the engine on went on with spraying wd40 on the pulley bearings, when I sprayed it there:
18cf1f89ee52e95ecee63c2ffb1655b4.jpg

It immediately went quiet. So I’m pretty certain about my diagnosis. Now to the parts that I’ll need:
59152506ef808bf23575dffa6d638924.jpg

b123a9719fedcfb1835645d707193154.jpg


Am I missing something?


Sent from my iPad using Tapatalk
 
Retroman said:
You're on the spot so to speak so if you say the problem is with the crank pulley - then I'll take your word for it. Usually these pulleys are "dampened" with rubber sandwiched between the centre section on the crank and the outer section holding the auxiliary belt. If that rubber filling breaks down, then you can get squeaks and vibration. No amount of spraying with WD40 or similar will make any difference and you will need to replace the pulley and central crank bolt.
Click to expand...

Wait, if I remove central crank bolt will it also let go of Crankshaft sprocket and I will need to remove timing belt as well?

Numbers 18 & 19
bce89ce5d9c758b75d1c77f58e73a569.jpg
 
Btw that's my auxiliary belt diagram,
And I can't find crank pulley bolts anywhere - as anywhere to buy them online

94b64a56e6b7a4071778f0bc7120c6d1.jpg
 
Last edited:
You must log in or register to reply here.

Similar threads

T
belts
Replies
0
Views
296
tazbiker
T
M
Screeching Brakes
Replies
2
Views
1K
mr misery
M
B
Seat belts
Replies
3
Views
639
brianriggs
B
Richard Appleyard
Loud screeching noise!
Replies
9
Views
7K
paddy
paddy
M
S3 Timing belts.
Replies
10
Views
9K
Maki65
M
Top
Back