I have an 2003HD 6.0L, 4L80e, 4.10 rear end. I love my truck, but there has always been something that nags me about this truck. It's cooling.

I live In Los Angeles and travel up to big bear (it's a 25 mile 1000' to 6500' climb) or on our way out of LA through Gorman (it's a 25 mile 1000' to 4500' climb).

In either case, there is a problem. The truck will cool the engine perfectly - never above 195 - unless I rev the engine above about 2900 RPM. If I keep it below, the fan clutch remains engaged and cools the engine, but if I increase the RPM's above about 2800, the fan disengages and the engine really heats up quickly (within 30 seconds it will climb and it will climb above 240 easily!).

Last weekend I went to big bear, and on the way up, if I kept the RPM's down, I was fine but if i tried to get above 30 miles an hour... it didn't overheat but didn't keep the engine "cool".

Again, the fan clutch does it's job but just until I get to 2900 or so RPM's and then it disengages.

I would like to replace the fan with one that is temperature sensitive (Since most of the time I don't need the fan to cool the engine without towing). Unfortnately, I've been unable to find a fan clutch that is documented to explain the speed upon which the fan disengages and at what temperature it engages..

Any help you might have would be most appreciated!

thanks!

Josh

 

Electric fans would probably take care of your problem with relative ease. They are also relatively cheap, as compared to some performance modifications you can do. You can find them on ebay for around $100-$200, or get a 'name brand' product for around $450 to $550. I don't know much else about them, other than I want some, haha.

I feel they will solve your problem, because when they are working properly, they begin cooling the engine when it reaches a certain temperature, in the effort to keep the engine at that ideal operating temperature.

Luckily there are plenty of others here that know a lot more about these than I, and hopefully they will post soon.

Here are some products:

From Summit. Pricey.

Other members of this forum have used much lower CFM fans (about 1500-2000) with great results, but what you decide to get is up to you, if you do.

 

yes the electric fans are nice. I would get some that are around 4000 cfm or higher. you might also want to try some cheaper things to. change the coolant, thermostat. I got my fans at summit they work good and do a nice job. they do draw alot of amps but they don't trun on much.