Fan clutch noise

[bcarson]

When pulling my 32 ft. Montana with my '05 DMax I hear an occasional but consistent roaring that I assume is the fan clutch kicking in for a brief period of extra cooling. The temp gauge doesn't show any movement, but for about a minute or a little longer the roaring continues. When not pulling a load I don't hear anything. Am I correct in assuming this is what I think I'm hearing? It's just noisy and a little worrisome, too. Any comments out there?:confused:

[DmaxMaverick]

It's probably the fan, and there may be no indication on the temp gage. As the thermostat(s) open, hot coolant is released to the radiator, and the now (more) heated air passes to the fan clutch, causing the engagement. With your 05 LLY, this is highly desirable. Anything that prevents overheating with the LLY's is a good thing.

You can verify it by comparing that noise with a cold start test. After an overnight sit, start the engine, let the oil pressure and voltage come up and engine smooth out (30 seconds or so), rev the engine to about 2000 RPM's or so. You should hear the same noise. A cold clutch should engage similarly to the operation when pulling hot. Once the silicone oil in the clutch fully circulates and warms up, it should quiet down and smooth out to normal operation.

[bcarson]

Thanks for the comments. I'll check it out, but that reinforces what I was thinking and I feel better.

[a5150nut]

I hope you have a pyrometer. If you do you will see how easy it is to get warm when pulling hills or into the wind. Use Manual range to drop a gear when your exhaust temps start to climb. Just backing off a little bit on the loud peddle will decrease temps too.

Being in the Pan Handle it is reasonably flat. But if you head into the hills watch your temps and do get a pyrometer.