Wierd whistling/howling - Diesel Forum

blwnsmoke · 10-20-2009, 08:19 PM

I have this wierd whistling sound coming from the engine area. It sounds like it is coming from behind the radio or glove box but it is definately under the hood. it happens at random rpms and quite often when I let of the pedal. When holding boost I hear it as well and can make it disappear by pressing hardly or lighter. This isn't the normal turbo whistle.. It is a completely separate sound. It is worse when it is cold out then warm.

Any ideas on what could be making this sound?

05superdutynj · 10-21-2009, 05:43 PM

Quote:

Originally Posted by blwnsmoke

I have this wierd whistling sound coming from the engine area. It sounds like it is coming from behind the radio or glove box but it is definately under the hood. it happens at random rpms and quite often when I let of the pedal. When holding boost I hear it as well and can make it disappear by pressing hardly or lighter. This isn't the normal turbo whistle.. It is a completely separate sound. It is worse when it is cold out then warm.

Any ideas on what could be making this sound?

i get the same sound! im thinking its something to do with the air vents ... but idk ,,,, let me know what you found!

**teamroper60** · 10-21-2009, 08:47 PM

Either your degas cap is venting or you have a leak. Do you experience puking? If so, that is where I would start. If you are not, then I would look at your y-pipe and CAC boots (you will need to take them off to inspect them as most often, the split in one cannot be seen unless you do).

blwnsmoke · 10-21-2009, 09:23 PM

Quote:

Originally Posted by teamroper60

Either your degas cap is venting or you have a leak. Do you experience puking? If so, that is where I would start. If you are not, then I would look at your y-pipe and CAC boots (you will need to take them off to inspect them as most often, the split in one cannot be seen unless you do).

To be honest I do not know if I am puking. The degas bottle is empty so it must be going somewhere but I do not see any fluid that was sprayed. The sound is definately coming from the passenger side of the engine. If I had to guess, I would say it is near the exhaust downpipe or intake tube near the top of the motor. It is closer to the firewall then the front.

KevinTamu · 10-21-2009, 09:35 PM

If it sounds like a tea kettle, I'd replace the Degas cap, I just recently replaced mine last week and it solved the problem. That annoying noise its worth the $10 it costs.

**teamroper60** · 10-21-2009, 11:36 PM

Quote:

Originally Posted by blwnsmoke

To be honest I do not know if I am puking. The degas bottle is empty so it must be going somewhere but I do not see any fluid that was sprayed......

That is not good... Do you have any idea how low on coolant you are?? You need to put in some coolant, even if it blows out the next time you drive it. If you run it low, you can be assured you are going to have problems with overheating, head warping, etc........

You can look at the aluminum foil looking stuff on the firewall for discoloration and either rule out or figure out whether the y-pipe/up-pipe is leaking......

djshum · 10-22-2009, 07:53 PM

I have seen a few with high pitched squeel from passenger side, rear of engine. It was a crack in the flexible portion of the up-pipe. The noise will usually change if you crawl underneath and apply some pressure to the pipe with a prybar. You can also pinpoint where it is coming from with a stethoscope.

blwnsmoke · 10-30-2009, 04:14 PM

Just wanted to update the guys who had the same issue. Picked up a new degas cap, the part number has changed again. The latest is 9C3Z-8101-B instead of A. The bottle took about 2 1/2 quarts.. no more whistle.. Seems the problem is fixed for now. Now to monitor the level. There was a little bit of white residue around the bottle.. almost looks like dried up salt. Hopefully it was just the cap that was leaking.

NoStatic · 11-22-2010, 03:18 PM

Quote:

Originally Posted by blwnsmoke

Just wanted to update the guys who had the same issue. Picked up a new degas cap, the part number has changed again. The latest is 9C3Z-8101-B instead of A. The bottle took about 2 1/2 quarts.. no more whistle.. Seems the problem is fixed for now. Now to monitor the level. There was a little bit of white residue around the bottle.. almost looks like dried up salt. Hopefully it was just the cap that was leaking.

I had the same issue as blwnsmoke...I have had this whistle issue for several years on my '06 6.0L. When it first started, it would only do it when it was real cold outside. Recently, it has been doing it all of the time. Today I loosened the cap before leaving the house, and no whistle. Drove 10 minutes to the store and tightened the cap before heading home. It took about 5 minutes for the system to build pressure and back came the whistle. I suspect that the valve in the cap is not sealing, probably due to puking coolant that has dried in the valve seat. I have the cap in my ultrasonic cleaner as I type. If that doesn't work, I will replace the cap.