'06 Dmax fan noise

[Stlheadake]

I know I am posting and asking a lot of questions, so please bear with me. My 06 LLY has tremendous fan noise on a 'cold' engine. For the last 3 weeks that I have owned it (bought it new), the temps here have been in the 40-50's in the morning. I start it, let it idle for about 10 mins, then head out easy. The fan noise is so loud in the cab I have to turn the radio up. The noise continues for about 10 mins or longer depending on the outside temps.

Then I'll hear the clutch kick out, and all gets quiet. I know that much has been written about the fan noise. I do know that if I let it idle long enough I get no noise.

Do others have the noise? Should I have it looked at? I don't know how noisy it should be, because mine is pretty loud!

Thanks for putting up with my million questions!

[rob from bc canada]

My 05 gives off a very little bit of fan noise (detectable when standing in front of the truck) when cold, but not so you can hear it in the cab.

Sort of amazing to those of us who have owned earlier diesels, that the noise we'd be concerned with would be the Fan noise!!!!

[AndyLBZ]

My 06 LBZ does the exact same thing. It has 8000 miles now and has not gotten any better. Some days it does it, some days it doesn't. I'm not too worried about it, but I would have to say that it is pretty annoying. It would be different if it was a noisy engine, but these LBZ's are ridiculously quiet. I have had people mistake mine for a piston slapping 6.0 liter.

[More Power]

My '01 has done this since new (now 53,000 miles).

When the engine is off, the silicone fluid inside the fan-clutch apparently migrates from the reservoir and into the fluid coupling plates. This combined with a cold fluid and clutch assy, cause the fan to engage after a cold start. Once running, most of the silicone fluid eventually (over a period of a few minutes) cycles back to the reservoir inside the fan-clutch. This uncouples the rotor and stator, and the fan-clutch disengages.

It's normal.. :)

Jim

[soot]

With ~13k miles on my LBZ, I'm surprised I've never heard the fan clutch engage yet. My old LB7 almost always did it when I first started it, regardless of outside temperature.

[DmaxMaverick]

It's the nature of the beast, so to speak. I'd be more concerned if it didn't make noise on a cold start. As MP stated, that's just the way they work. They are fluid couplers, and are not within their operating spec. when cold/stationary. The only fans I've seen (heard) that didn't make noise, had bad clutches.

[REDTRUCK05]

I know I am posting and asking a lot of questions, so please bear with me. My 06 LLY has tremendous fan noise on a 'cold' engine. For the last 3 weeks that I have owned it (bought it new), the temps here have been in the 40-50's in the morning. I start it, let it idle for about 10 mins, then head out easy. The fan noise is so loud in the cab I have to turn the radio up. The noise continues for about 10 mins or longer depending on the outside temps.

Then I'll hear the clutch kick out, and all gets quiet. I know that much has been written about the fan noise. I do know that if I let it idle long enough I get no noise.

Do others have the noise? Should I have it looked at? I don't know how noisy it should be, because mine is pretty loud!

Thanks for putting up with my million questions!
When you start pulling it will be really bad.

[REDTRUCK05]

With ~13k miles on my LBZ, I'm surprised I've never heard the fan clutch engage yet. My old LB7 almost always did it when I first started it, regardless of outside temperature.
Not to be rude but I have owned too many other trucks that had no problems with heat or fan noise. Its loud! Its a huge drag on the engine, and with a truck that is getting 9-10 mpg pulling already, its not a good design.

[DWRAT]

Not to be rude but I have owned too many other trucks that had no problems with heat or fan noise. Its loud! Its a huge drag on the engine, and with a truck that is getting 9-10 mpg pulling already, its not a good design.

No doubt about it, it sucks the power right out of the motor. But on the bright side, if it didn't come on and cool the truck down you would be left sitting on the side of the road. A lot of the LLY Duramaxs run hot when towing from what I have learned. The 2006 trucks were totally redesigned as far as the cooling and intake goes which is suppose to correct the hot running LLYs. As far as the new LBZ Duramax, time will tell.
Dan

[REDTRUCK05]

No doubt about it, it sucks the power right out of the motor. But on the bright side, if it didn't come on and cool the truck down you would be left sitting on the side of the road. A lot of the LLY Duramaxs run hot when towing from what I have learned. The 2006 trucks were totally redesigned as far as the cooling and intake goes which is suppose to correct the hot running LLYs. As far as the new LBZ Duramax, time will tell.
Dan
When the fan clutch comes on, the temp reading on my edge does not seem high. When it releases, (often 6,8,10 miles later the temp reading hasnt changed much. This tells me that the fan is reading ambient temp of the engine compartment. But both my dash gauge and my attitude says ok. Any Idea if gm would give a break on a retro fit into a 06 design?

[REDTRUCK05]

My '01 has done this since new (now 53,000 miles).

When the engine is off, the silicone fluid inside the fan-clutch apparently migrates from the reservoir and into the fluid coupling plates. This combined with a cold fluid and clutch assy, cause the fan to engage after a cold start. Once running, most of the silicone fluid eventually (over a period of a few minutes) cycles back to the reservoir inside the fan-clutch. This uncouples the rotor and stator, and the fan-clutch disengages.

It's normal.. :)

Jim
I agree, this would be fine in by itself. But to be pulling a lite load and have it come on for extended periods of time just is not right.