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Strange Whistle noise

12K views 7 replies 4 participants last post by  BigGreen06 
#1 ·
For the past 6 months I've been getting this high pitched whistle coming from the engine bay when I accelerate, usually while driving normal speeds (35-45). But lately its happening more, seems like every time I press the pedal it happens, and if I let off the pedal it stops right away, if I continue through the acceleration process, then it lasts about 4-5 secs. My thought it is coming from the turbos, whether it is a problem or not, I havent got a clue.
Any help is greatly appreciated.
Thanks.

James.
 
#2 ·
Could be the degas cap on the coolant tank. Black cap on the clear tank. Drivers side firewall. Check for residue on the outside of the cap. If it loses the ability to hold pressure, it can push air and coolant out the cap and cause a whistle. Sounds like a tea kettle under acceleration under heavy boost.
 
#3 ·
Check for soot on the firewall. Sounds like it could be a leaking up pipe.
 
#4 ·
Where along the firewall, from above or below? And which side?

Also I don't think its the coolant tank, because its at its normal fill line. And there isn't any trace of coolant anywhere on the engine.

James.
 
#6 ·
Could be a boost leak in the I/C system too like a bad/loose boot or cracked pipe. Your I/C itself could have a hole in it. Wife's Dmax had the exact same symptoms so I built a boost pressure tester to find it. Was a hole in the I/C hot side pipe.
 
#7 ·
I read an article I'm the latest Diesel Power about the stock boots for the intercooler and turbo not being able to take the heat and failing quicker than they should. So already planning on getting them upgraded. Thanks for your input.
 
#8 ·
I got under truck yesterday while it was on the lift getting oil change, from what I could see, which wasn't much, there really isnt a lot of room under there, I haven't got a clue how you guys have fit your hands up there. But the left side looked good, the rightside though had a rubber boot on it that looked a bit degraded.

James.
 
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