Squealing under load/boost

[Boyaaa1]

Hi all,
Looking for some advice or answers, i have recently bought a mk1 Leon Cupra r and when pushing the car on full throttle and at low revs to build up boost I can hear a squealing noise, at first I thought this was loss of traction and just the tyre squeal but I have managed to load the car under boost and brake slightly at the same time thinking this will load the car further and this emphasises the squealing even more, I notice it mostly when in a high gear at low speeds, can anyone shed any light??
Thanks in advance!

 

[Lukesmith93]

Boost leak/sticky turbo vanes/over boost all things like that have to check around them


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[Boyaaa1]

So really I should start with a smoke test? And then correct any boost leaks then go from there?

 

[Lukesmith93]

If it's on standard boost pipes I'd say 90% chance it's got at least a small leak.

The squealing is more likely to be the vanes. Could try the mr muscle cleaner. And/or forte diesel turbo cleaner is a very good product.


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[Fmxvxx]

Worth checking the auxilary belt as well as this can cause a squeeling when it has worn out, as for checking for boost leaks a smoke test is your best bet you could also spray brake cleaner onto the connections and listen for a change in engine note

 

[Boyaaa1]

So do you mean remove the tip and spray some cleaner in there and what exactly are the canes? Do you mean for the actuator?

 

[Boyaaa1]

Also at idle imgetting a squeek coming from my aux belt, could this be what is screeching under load/boost??

 

[Lukesmith93]

Spray some belt slip on the aux belt see if that helps to start. Just to eliminate that noise first.


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[pedro1989]

It's a petrol cupra r isn't it? No turbo vanes if so.

Check the play in the turbo, could be compressor hitting the housing
Check for boost leaks
Check turbo to manifold gasket, is it blowing from there? Every time I've gone through one it squeals like hell on high boost

 

[Lukesmith93]

Aha silly me I assumed it was diesel I thought I was in the diesel section sorry guys


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[Boyaaa1]

I've tried rubbing candle on the belt while running and that stopped the noise at idle but was still getting that screeching at high boost/load, I'll have a feel about on a ramp see if there's any air leaking out the gasket and check for dreaded play in the turbo, praying it's not that

 

[eddie_cupra]

Screeching on boost sounds like a failed turbo to me. Sorry. Remove the TIP and give it a wiggle (if u can get to it?) It shouldn't have much play (about 0.1mm is normal I think).

Good excuse for a hybrid and a remap though!

 

[Lukesmith93]

Might sound stupid but what way would they have play. Side to side or in and out?


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[pedro1989]

A little side to side is ok, almost any in and out is bad. If it's bad enough to cause squealing though it'll be moving side to side a lot!

 

[Lukesmith93]

Just wanted to know for when I check mine thanks


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[pedro1989]

Aha, apologies, didn't realise you weren't the OP

 

[Boyaaa1]

I was hoping it wouldn't be the turbo, I take it to remove the tip I'll need a ramp?

 

[Lukesmith93]

Or a jack


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[pedro1989]

I was hoping it wouldn't be the turbo, I take it to remove the tip I'll need a ramp?

It's worth checking anyway

You shouldn't need a ramp, it's a bit fiddly the first time you do it (can't really see anything), but it's pretty easy the next time, all from above the car.

 

[Boyaaa1]

Yeah I definitely need to check it, I'll attempt it from up top