I was towing for the first time with my 02 2500HD D/A in the NC and TN mountains and after climbing a pretty good incline I would hear some sort of blower sound kick in. It ran for a few minutes and stop. Actually sounded kinda like transmission had downshifted and the engine was reving but it wasn't. All temps were fine and it didn't seem like anything was wrong but it was somewhat loud mostly a bit surprising. So the hopefully not too terribly stupid question is what is it? Any reason for some concern?
If it is relevant the trailer is about 6000lbs empty so I would guess maybe approaching 7000lbs.

Thanks, Sparkyp Edited by: sparkyp

psss you dont have a blower you have a turbo.

No reason for concern. Temps got high enough for the clutch on the fan to engage. The roar is from the fan moving all of that air through. Once the temps dropped a little bit, the clutch disengaged.

The sound you are hearing is an aux. engine fan that kicks on when things get a little warmer than normal. Like in your situation, pulling a load up some grades. Read somewhere where it is triggered by higher intercooler temps.


Everything is normal.

You will hear it a lot towing in the mountains on hot summer days.http://www.dieselplace.com/forum/smileys/Approve.gif

Thanks guys.
I probably should have mentioned that it sounded like it was coming from within / under the dash.
Never the less aux fan kicking on due to intercooler temps sure sounds like a good technical explanation.
Everything else was just about wonderful. Just about only because the fuel economy was a little less than I expected for a 6-7k pound trailer. But then again I was always maintaining speed limit and the trailer pushes alot of air.
I suspect that if I were running across oh, say Kansas in the plains it would have been better. (unless I had a 40mph headwind).

Thanks again guys.
Sparky

You will also hear this fan noise on cold mornings as well. This is because the fluid in the fan clutch is too think to allow the fan to disengage. Once the fluids warms up a bit, about a couple of minutes or so, the roar dissapears.


I heard it quite often towing our 5er in the mountains on hot summer days last year, as Chipper mentioned. No worries.


Bob

No Such Thing as a Stupid Question. Only stupid people!http://www.dieselplace.com/forum/smileys/Big Smile.gif

MINE DOES THE SAME ITS NORMAL.......SORRY ABOUT TURFMOWER SOME PEOPLE ON HERE ARE A SMARTASS SOMETIME