My truck is stock, except for a new set of injectors. I have the stock airbox, and stock exhaust. The truck has 189,000 miles on it, and runs great. When I am on a hard pull, usually going uphill, and at fairly high rpm's, it will develop a whistle. Sort of like a forced air leak. I have checked and rechecked the intercooler boots, and tightened them. I have visually checked to see if I have an exhaust leak at the turbo, and checked/replaced the gaskets on the intake horn (replaced during the install of the new injectors). The whistle was there before and after replacing the injectors. It does not do it all the time- usually when it is in the 40's and 50's (outside temp). When it does whistle, there is no loss of power, no white or black smoke, and backing off the throttle slightly will make it go away. Any ideas? Anyone experience a similar noise?
If something doesn't jump out at me, or someone says "Hey, I had the same thing, and after I replaced the wiggly gear on the wobbly shaft, it went away", then my next step will be to replace the intercooler boots. I can advance the throttle at the injector pump, but it won't make the noise. It has to be in a hard pull. So, it is hard to hunt it down. Unless someone wants to ride under the hood, and listen for me.
BTW, engine temp stays the same, and there are no CEL's. Just a noise

 

small hole in intercooler? i have friend with a super duty that has hole in his, still driving it as little as possible till he gets the money to fix. i'll ask him how he figured it out and what it sounded like.

 

I think I know exactly what you are talking about. Sounds like sort of a raspy whistle I get usually above 18lbs boost, certain temperatures. Hasn't done it lately, once it warms up to about 40 or so I'll hear it every now and then. Let me know when you find out what it is, I've wondered if it's the wastegate somehow opening a bit, as mine is usually disconnected.... I've learned to live with it.

 

I wondered about the wastegate. I don't think it's a boot, because I expect to have a performance loss with boost loss, but I could be wrong. At this point, the only symptom is the noise. My first concern is am I damaging something? Makes me wonder, since it has been there, on and off, for some time (6 months or a little more), with no ill effects (that I can see, yet). Why wait 6 months to ask? Well, I have exhausted my current options (look, listen, tighten, try to create conditions to replicate it, etc), so now is the time to pick brains.
Mark

 

not boot,intercooler it self. i also agree that you probably should notice loss of power or some extra smoke if it was a big leak. could be small crack in a part that only leaks under full boost.

 

id try takin the air filter off for a test run and see it makes any difference. cud it be somethin on the vacuum side of the turbo. between filter and turbo. ive taken the whistle ring out of mine so i have alot of turbo whistle

 

We had a ranch truck that would whistle when pulling we you got on it an then let it it out go a way until you got back on it it had a few tiny pin whole in the exhaust manfoild. I didn't have a problem with power or anything. It only had about 60,000 mile. Hope this helps.

 

Sorry my was on a 24v on a 12v

 

If you have a boost gauge check the tubing and connectors.
If the tubing was kinked during installation it can develop a small whistling leak.

 

I don't have a boost gauge.
If it were the intercooler itself, why would it only do it at certain temps? Being a hard part, why wouldn't it do it all of the time?

 

temp thing i cant explain, my findings on leaking only under full boost is because i have a three inch sch 80 plastic water line that only leaks water when pumps on. i know someday that it will break but it is crazy because it is so thick and can open up and close and still only leak under pressure. i realize that a leaking cooler is a worst case deal but just a thought, i hope its not that.

 

I hope it's not, either, but I am a realist- it is what it is. At this point, though, I don't know if it's that. Today, I had a full load of wood in the bed, and a full trailer load behind it. I pulled it hard, and it never whistled. Later, when the ambient temps were up a little, it did it. I think that I am going to look at the wastegate, and see if it is functioning.

 

got me, sounds like if it was going to leak it would have today for sure. i just got off the phone with my friend with the ford that leaks, he hasn't personally seen hole in his cooler his mechanic told him about it when he was changing oil and that dude shady as can be so? good luck and keep posting.

 

one thing you might try is taking the hose off of the turbo and plugging it. i have found oil filters work well for this. then attach air to a port somewhere in ur intake system and charge it with 30 to 40 psi and listen for air leaks. with the motor not running it shud be relatively easy to find

 

That is a good idea- I will try that. Thanks!