dodgestang

Last week my truck starting making an 'interesting' new noise.

When on the throttle and above about 2k I hear a loud blowing/sucking noise. Almost sounds like the defroster is on...but different octave.

When I let off the throttle even if the truck is still above 2k....the sound goes away.

The little voice inside my head is saying....pin hole somewhere in the intercooler or lines to it...the other little voice inside my head is saying its on the intake side and its just the sound of air being sucked in.

The truck still has plenty of power...ie still generating boost at least to some degree, with no boost gauge installed I can't read if I am getting some parasidic bleed off.

The only other 'symptom' (if you want to call it that) is average fuel economy has dropped from 20.6 to 19.5 for a tank of gas. Now, the fact that I have been troubleshooting this blow/sucking hiss for the last week combined with cold starts so I need longed warm ups is prob. driving that.

The truck (2005 3500 CTD) has a controller box installed (SP Diesel) and the noise is there regardless of box installed or not (yes I disconnected and reinstalled it as part of another trouble shooting excercise I was doing with a battery drain issue).

This is my first diesel and while I don't expect 'virtual' trouble shooting help to net me too much, I am wondering if any of you salty diesel dogs have any had anything that sounds remotely like I am poorly describing?

staarma

If you have one of the 05's with the plastic intercooler you may have a crack in it or simply a leaking boot or clamp on a hose going to or from the intercooler.

rmalone

I would think you can check the boost-side of the equation (turbo compressor outlet up to the intake horn) with soapy water like a leaky tire. On intake leaks (I have heard either and propane) I know I wont do it, I have also heard of putting positve pressure on the intake and and using the soapy water. I would be careful on the intake side.

dodgestang

I took the intake stuff out this evening to gain access to the piping leading from the turbo to the intercooler (inside cab noise is very definetly being produced near the passenger side firewall), I figured this was the best place to start looking. I un-screwed all the clamps and tried to move the soft flexible to hard line connecting peice thinking perhaps a gap had developed and I could reseat. I could find no 'obvious' holes in the parts. I went so far as to shoot pressurized air from my compressor down the intake and spool up but somehow I don't think I can generate anything close to what the motor would at 2000 RPM when the blowing sound starts

I buttoned it all back and the blowing sound is still there. I will have to wait till I can get a helper that I REALLY REALLY trust before any possibilty of sticking my head under the hood looking for blowing bubbles while someone power brakes the car.

dodgestang

I thought that this might have been the case....but closer inspection reveals an alumumin intercooler.

BigBlue

You can pressurize the system with your air compressor to about 20 psi and spary soapy water and that would work better than having someone powerbrake the truck while your in front of it.

dodgestang

Yes it would be a good idea, however, do we have know what boost level the CTD produces at 2000 or do you think it just so happens that 2000 is the RPM at which the leak becomes audible in cab as apposed to RPM when it begins pushing out from whereever it is leaking?

bluepp

Check all those clamps on the turbo tubes. The rubber boot will slip out from under clamp. Usually happens on the bottom where you cant see it , but you can feel it

rmalone

I wouldn't think that the intake side (negative/vaccum pressure) of the system would develop near the pressure as the compressed side (positve pressure), hell, soapy water the compressed side at idle and see what happens if need be have a very good friend power brake it. On the intake side an air-compressor seems like the only way to develope positive pressure, if you rev to 2000rpm and spray the intake tract it will just suck it in and try to burn soap, and likely not show you the leak.

dodgestang

Thanks all for the help.

It was a broken intercooler.

The tank in the car had an aluminum center and plastic side panels which had become seperated. Dealer put in a replace all aluminum/welded unit that was instock, mentioned that they have been having problems like this which is why they had it in stock, and I'm all back together.

rmalone

Excellent glad to hear it worked out.

Dan_K

Had the same problem with mine. It happened during summer, and progressed to the point that I heard it all the time. Dealer fixed it in 2 days.
DK

a.c.kidd

I wonder if that is what is wrong with mine (04.5 dually). I noticed a funny noise from the front of the engine compartment this morning at idle.....performance has been CRAP. I punched it getting on the freeway this morning with 10k trailer on back and no power at 2000 rpm in 5th gear. Mileage has been around 14 pulling empty 4k trailer and 12 loaded to 10k. I'm really disappointed in this truck compared to my 01 HO. Had reflash 4k ago and thought it had improved the fuel mileage, but now it is terrible again. It takes a miracle to get the overhead to show 18 running empty.