Brand New Drive belt squeal

Soberts

Is it normal for a drive belt to squeal a small bit when it's brand new? I have just replaced the timing belt, water pump and both the alternator pulley and AC pulley on my Audi A4 and under reasonably quick acceleration there is a slight squeal for about a second or two as the turbo kicks in, is this just the belts bedding in or is there an issue with alignment or tension?

sandydan

id surely hope not T-belt ,a new tensioner is usually fitted as well and if it were slipping the timing would be out by now, that belt is notched so unlikely and starting would be difficult. probably fan belt slipping or clutch squeal,ie release bearing.most likely fan belt id say since pulley was replaced,was belt not replaced when pulley was replaced ,maybe not tightened enough.

visual

I be checking aux belts are tension correctly. Sounds like one is slightly lose

Soberts

I had another listen and i actually think its the turbo making the noise, while i had everything apart i checked the play in the turbos turbine shaft which may have thrown it a small bit, the play was a little much for my liking but it never made this sound before the belt change, so i may have nudged the bearing very slightly going to pull off the intake pipe and have another look in tomorrow.

sandydan

i had turbo squeal in turbo and it turned to whistle ,something went into rotors and chewed it to shreds, play in shaft is usually first sign of turbo bearing trouble, hope its not that serious.

Soberts

i had a look into the turbo this morning and yes there is a small bit of play in the compressor side but there is no scoring or signs of wear on the housing, i could not get to the turbine side without a large amount of work! there was a small pooling of oil on the compressor side also which is obviously not great either, a turbo recondition definitely seems to be on the cards soon

When you say you used to have turbo squeal, did it happen continuously or was it just at certain times like the initial onset of boost?

sandydan

Soberts wrote: »

i had a look into the turbo this morning and yes there is a small bit of play in the compressor side but there is no scoring or signs of wear on the housing, i could not get to the turbine side without a large amount of work! there was a small pooling of oil on the compressor side also which is obviously not great either, a turbo recondition definitely seems to be on the cards soon

When you say you used to have turbo squeal, did it happen continuously or was it just at certain times like the initial onset of boost?

just was squeal one or two days ,OH drives most of time and just mentioned it ,end of week it was whistling badly and got worse, but maybe its only my car will do that, but if oil in compressor side id start pricing ,bearings are starting to go imo hope not but..

Soberts

I got a second opinion on the noise and we both have come to the conclusion that it's not the turbo but the gasket between the turbo and exhaust, I'm going to pull it apart and stick some gasket sealer on it tomorrow and see if it sorts the issue

sandydan

Soberts wrote: »

I got a second opinion on the noise and we both have come to the conclusion that it's not the turbo but the gasket between the turbo and exhaust, I'm going to pull it apart and stick some gasket sealer on it tomorrow and see if it sorts the issue

im very interested in that , please post and let us know how you fare out. ive third turbo put into avensis at 170,000km or 120,000 miles

Soberts

yeah no problem, i will post back here with results when i have them! i am quite confident that this will fix the problem as it makes most sense as there is no smoke or performance issues and it only started the noise after the rebuild

Soberts

UPDATE: Added gasket sealer to the turbo outlet/downpipe gasket and the problem is solved, i have only heard the noise once since i have done it so it was definately the problem, i think a new gasket altogether may not be a bad plan :P