has anyone else experienced problems with their clutch fans? the last one is only a few months old. have replaced more than once. I find they kick on too late at too hi a temp , 200 degrees or more. rad is good. and aftermarket gage is a expensive one, so I am keeping pretty good tabs on it. to me on long pulls in the mountians it should do its job better.

 

I found as soon as I bought my truck that it wouldn't pull a double up Homestake pass without stopping to rest and cool down. Mishimoto aluminum radiator solved the problem. Low stall torque converter helped as well. Also if you're running an automatic, you need the fan assisted frame mounted cooler to keep up with the heat generation.

 

I do not know at what temp my clutch fan starts to engage, but the factory gauge is getting close to the high side when it does. It comes on hard and loud and cools things down no problem. My truck has the NV4500 so As Mr. Martin mentioned your auto might be the culprit.

 

thanks for the info. my converter has been replaced with a better one also fan cooled extra heat exchanger for tranny.also tranny gauge installed . so I still question these clutch fans. local parts store says one of his customers bought a real good one and was quite pleased. so did the Mishimoto make a difference, or did it make a big difference as far as you are conserned?

 

The Mishimoto aluminum radiator made a huge difference. Our copper radiators are a quarter century old. They get plugged up a bit, and also the solder joints between the tubes and the fins corrodes, eventually letting go, but it has to reduce the heat transmission before that point.

I'm on the second one. The top mounts were a bit high on both radiators. I think excessive mount pressure caused the first one to leak. They replaced it on warranty with a service fee. I made some shims for the second one.

 

my rad is good just had it done but I think these trucks when you start to build a little more power out of them are vary border line in the cooling area.thanks for the info I may see how many smackers one mite cost.

 

Fan shroud in place ? Without one, the truck doesn't cool well at all.

What brand fan clutch you running. Cheaper the worse they are. Took me a fee tries till I found a reliable one, even though it's MIC

 

A little over $600

 

so what problems were you experiencing with your clutch fans that made you change them?

 

No longer engaging, causing the A/C system to overheat and blow freon out the high pressure relief valve.

Scared the daylights out of me. LOUD EXPLOSIVE NOISE from under the hood.

Installed this, and no issue since



Make sure you check your application to see if it's the same as your year / model.

 

Heres what it very well could be. A partially plugged radiator. Ive got over 1 Million miles and have had this experience before. Ive rodded out my radiator several times because what happens is the bottom 1/3 of the tubes become plugged with silicone slime from the coolant. This stops hot coolant from going through the lower 1/3 and this cooler air blends with the hot air from the upper 2/3 of the radiator delaying the engagement of the fan clutch. If you run your truck just long enough the cycle the thermostat once, shut the truck off and run your hand down or use a thermal gun down the middle of the radiator from top to bottom on the fan side of radiator.. You will feel the top 2/3 is hot the lower 1/3 is cool because coolant isnt going through.

 

so I watched temp pretty close today. no trailer etc but when it got to about 205 degrees although I could not hear the fan kick in temp then started to slowly go the other way. my hearing is not great so at least the clutch is working somewhat. hot day big load?

 

My truck empty never runs hot, even on hot days. This is of course with a clean radiator. When the fan engages, i can feel and hear it. Have you checked the core like mentioned in earlier post?

 

I would be very suprized if it is the rad. to my knowledge it is good. however this truck is not stock. the fellow that has done work on it. who is very knowledgeable on them says when pump is cranked , bigger injectors, timing bumped, turbos changed it has a tendancy to build more heat.