Funny noise???

[JWey]

Hi Guys,

I have an 08 5500. It was sitting in my shop idling for about 20 minutes today and all of the sudden it started making this funny noise, almost like someone drilling through a piece of steel with a very sharp bit, coming from under the truck I think. Kind of higher pitched sound. I panicked and turned the truck off right away. Started it back up and backed out of my shop. It made the noise again if the truck was idling but as soon as I gave a bit of fuel it would stop. Is there a regeneration sound or something like that that happens? Seems to be running fine.

Thanks!

 

[Cosmo]

Is it cold where you are? Does it sound a bit like a jet turbine? The variable geometry turbo will constrict the exhaust side and engage the exhaust brake to warm the engine up faster.

 

[Hoefler]

Exhaust brake. The colder it gets the louder the whistle.

 

[JWey]

Thanks guys,

It did sound a little like a jet now that you mention it. It was probably 25 to 30 degrees when it happened. The motor had been running for probably 20 minutes before it happened, does that make sense? Thanks again!

 

[HBarlow]

Yep, it makes sense. I agree with the earlier posters.

 

[JWey]

I used the truck today on the farm. Every time it was running it was constantly doing the same thing. It was also blowing some smoke when it was making the noise, normally the truck doesn't smoke. The temp gauge was around 190 to just under 200 and it was still doing it. Normal?? Thanks.

 

[PFranzese]

If it was cold out the exhaust brake could have activated to keep the temp up.



Maybe someone can chime in on this; the next time it does it would turning off the exhaust brake cause it to disengage and make the noise go away?

 

[JWey]

Taking it into shop next week, will let you know what is going on. Thanks again for feedback!

 

[Cosmo]

Where are you located? If it's super cold, the exhaust brake would kick in every time you were at idle - but it should kick off when you get on the throttle. As far as smoking while doing it - no, that doesn't seem right. Maybe the truck is stuck in a DPF regen neural loop or something?

 

[Hoefler]

What color is the smoke?? When it is cold out, you will get condensation in the exhaust system. If it is white and clears up, I would say you are looking at steam as it warms up and boils the condensation out.

 

[JWey]

The smoke is white when this happens. It is more than some condensation though. Taking in to shop this tuesday for some maintenance items and this as well.