Have a 2004 1500 with a 4.7 it trys to over heat. rad looks good. belt are good changed stat. new antfreeze any ideas??? Also how do you check a clutch fan?? Thanks

You can't test a fan clutch; if in doubt, the factory says to replace with a "known good unit".

Go back to your rad and pressure wash the living daylights out of it. You should have clear water flowing out of every inch of it. Spend at least half an hour at it.

Over time, dust settles on the bottom row of fins and keeps getting worse.

Unhook the heater core and flush it out too.

Easy job on those, grille raises with the hood. Not like these new ones where they went away from that obviously great idea.

Only way I know to test for the clutch fan is to listen it to it. They roar when they are working, you can't miss it. Most vehicles do it cold when you first start out for a few seconds.

You sure it overheats? Maybe sender?

Thanks I will go back and check the rad and take a temp gun and check the temp at rad and stat houseing it great to have a place to get a answers and ideas. Thanks

Back in 1995 the FSM for Rams has a test for the clutch fan that involves using a heat gun aimed at the fan clutch and listening for the change in sound when it thermally locks up and raises the rpm of the fan to engine speed.

Back about 1998 when I tried this test I realized I had a 12 volt powered adjustable Stroboscope with a digital rpm readout from mining work that I had bought to field check the rpm of pump pulleys and electric motors. I got it out and found that i could easily measure the rpm of the fan, and the boost in rpm when the Magnum 5.9 V8 fan clutch locks.

The cost of these has come down since the 1980s:

https://www.amazon.com/Landtek-Instrumen...rds=Strobescope

My fuzzy memory tells me the early 2000’s 4.7 V8 thermal clutch slips quite a bit more when unlocked because it has a lower viscosity silicone fluid as a EPA fuel economy improver. When Chrysler press release came out that year and touted that change I thought about buying one and attempting to use it on my 1995.

"test" . . .see if there is play on the shaft . . . then feel if it is "free wheeling" (free wheeling) when cold . . . feel if it is "locked in" (not slipping) when hot . . . .

Viscous fan clutches never really "lock up" in normal operation. Like a non-lockup torque converter, there is always some slippage.

You could get the engine hot and place a fender cover over the grill and see if it stay's there. Alot of time you can just see the fan just spinning slowly and not drawing air across the radiator. Also if the engine is hot and you turn the engine off but the fan keeps spinning for a bit it's shot. Going the other way if the truck sound like it is "roaring" while driving in normal temp it maybe stuck on. Many customers think their transmission is slipping because they hear this load roar but the truck is just going down the road normally.

I have a piece of cardboard at work to slide in front of the radiator. A/c off, bring the rpms up and sit and wait. Temp gauge will usually creep toward 3/4 before you hear an audible difference. Temp reading on scanner will be 220-240 depending on model.