XSeries-forum

Hi all, The turbo blew up after 100k miles, so it's been replaced with a Garrett one. Since then, around 2.5-3k revs under load there is a squealing noise (similar to balloon having the air released when pinched).
The turbo has been doubly checked, it's fine, so is this one of the many pipes that can't handle the pressure now it has a new turbo? The biggish pipe in-front of the turbo (about 2.5-3" diameter) has also been changed plus the actuator - it still makes the noise. Has anybody else had this and found the cause??

Thanks in advance

Sounds like a split in one of the hoses

Thanks Ian. Are some more prone than others to split? Which hoses do I need? Are they changeable by a DIY mechanic (me) or is this best left to an Indy to sort???

honestly i don't know but i'd have a stab at it rather than take it to a garage

All pipes easy, fidly and some a tad tight etc, but easy enough. I'm fighting lost power issues and had them all off several times this last few weeks. If needed let me know and ill explain as needed.

What caused the last turbo to go? Did you change it or someone else? Did they clear all debris from everything, properly?

Have you changed seals on all the hoses, cheap and easy fix and if one torn, that could be the balloon neck wobbling as air pushes past, if you get my drift.

Does she cry at those revs if in park being revved up? If So, can get head in and narrow down the location.

Are you sure the compressor or exhaust turbines aren't catching the casing though, as I replaced my turbo, only to be treated by a scratching screech sound when boosting, and the compressor blades were catching the casing. Was visible marks on housing after 3 miles!

Where did you get turbo from, I still need one lol? And what torque was it put on to manifold with?

Was the replacement turbo and actuator OE speck, I mention this as many years ago my son replaced the turbo on his Integrale and was sold the wrong actuator which allowed to much boost, blew a hole in a pipe which gave same symptoms as you describe, unfortunately he replaced the pipe with a silicone hose and this allowed the pressure to blow a hole in the piston. Probably doesn't apply in your case, but just in case

ive had a recon turbo and new manifold a few weeks ago, it also makes this noise, ive had the intake pipe of the turbo cant se any markes/scoring where the compresser wheel may be catching , ive changed all the seals just previous to having the new turbo, but i didnt have the intercooler pressure tested also checked all hoses couldnt find any problems at all, anoying >:(

let me no if you manage to cure the noise

[quote="Trevor"]
Hi all, The turbo blew up after 100k miles, so it's been replaced with a Garrett one. Since then, around 2.5-3k revs under load there is a squealing noise (similar to balloon having the air released when pinched).
The turbo has been doubly checked, it's fine, so is this one of the many pipes that can't handle the pressure now it has a new turbo? The biggish pipe in-front of the turbo (about 2.5-3" diameter) has also been changed plus the actuator - it still makes the noise. Has anybody else had this and found the cause??

Thanks in advance
[/quote]
If the turbo has been changed for a different make, maybe the air outlet diameter is slightly different and the seal isn't doing its job properly where the hose to the intercooler joins the turbo, I had the same. Ouse on a truck once and it was a loose seal on the turbo/ to aftercooler pipe.

Thanks for all the replies guys. The garrett turbo was fitted as the 1st one had oil starvation due to the high pressure feed pipe being blocked. It was installed by an indy that services 3 other cars that belong to the family Z4m, E220 & 640d. We've never had an issue with him, but this seems to have him & his mechanics stumped. They've tried pressure testing the whole system but nothing shows up. The exhaust manifold has been skimmed as it was slightly warped. They've changed the all the pulleys as well. Could it be, that as its been mapped to give a bit more bhp (it became sluggish with the original turbo) that the new garrett turbo is working too efficiently, the pressure (I think they said 2.4) is right up near the top end of the pipes capabilities? Does logic say - remove the map to see if that cures the noise?

an update. The 3 remaining pipes were changed, they haven't cured the noise. As it only happens when you're giving it the full beans, we're going to live with it for now (the wife drives it the most). Hopefully one day it'll be sorted, but until then.....  O:-)

[quote="Trevor"]
an update. The 3 remaining pipes were changed, they haven't cured the noise. As it only happens when you're giving it the full beans, we're going to live with it for now (the wife drives it the most). Hopefully one day it'll be sorted, but until then.....  O:-)
[/quote]
The wastegate relief pressure is probably set lower than the previous turbo, it will open to prevent overboost.
It's probably had an over aggressive map.
Loads of members on here use Jason from BW Chiptune, he's a member on here.
Look at this example of over boosting

Or it could be the hot weather. It brings the shrill crickets out.

The shrill noise is the Turbo working well... a lot of the seals are simply moulded "O" rings in the clipped on pipes.

**I used to get the farty noise from where the intake pipe joined the EGR unit from the condenser... farted like a squelching pensioner with zero Butt control, combined with turbo whistle.

I solved the issue with a bead of gutter sealant prior to push fitting the pipe to the aluminium flange...

If you use any sealants.... Only put it on the MALE side of the joint, so it does not risk being squished into the pipe bore...

Final update! The map was changed to std - this didn't make the noise disappear. The Garrat turbo gave up the ghost last Saturday (didn't last very long). It was towed back to the garage, they had to empty the exhaust & intercooler of oil (it was a right mess). Since having another garrat turbo fitted & collecting on Weds, the X5 goes like a train & has no noise. Who knows whether it was the old turbo? or with the garage removing the exhaust/intercooled, they refitted something differently and this has rectified the noise? I'm just happy it's finally fixed... ::)

Hi guys, do you think it's worth a preventative rebuild, 140k

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