Just like the title says. My turbo is making some aweful noises.....sometimes.....that is the weird part.

To preface, this turbo was new about 10K miles ago, and it makes boost perfectly, shows no shaft or end play, and shows no sign of housing contact with the compressor wheel. It is an HX35.

When I first start and run the truck for say the first 10 miles it makes no noise. But, after steady driving for 5-10 minutes, coming to a stop, and accelerating again, it screams. It almost sounds like it is contacting the housing, but it has been doing it for a month or more with no change. If you take it through a couple boost cycles or hold it at around 15psi for 4-5 seconds the noise completely goes away untill the next slow down. Also the noise only starts above 7psi which oddly enough is the cruise boost pressure. It also goes away if you push it on up to 25psi.

I have tryed to make a correlation between EGT and/or engine temp and the noise, and there does not appear to be anything there. I also have a ball valve type boost controller on it.

I keep thinking something will let go or it will start loosing boost and it has not happend. The noise has become a little more often, but not changed much.

I have checked turbine/CHRA bolts and they are tight. I have backed off the cheater valve on the wastegate and nothing changed.

Any ideas anyone? I am at a loss.

 

You have a small boost leak.

 

Okay, this makes sense. Any ideas on finding it? I did look everything over and did not find anything noticeable.

 

Pressurize the system and spray it down with soapy water.

 

Well, that makes good sense too. I consider myself to be fairly sharp on this stuff, but I now feel kindof dumb. Thanks!

 

Check all your boost boot connections, sound like you may have a tear in a boot or a loose clamp.