fan clutch or radiator?? help!!!

truck overheating over long period of time. doesn't go to red or anything, but does go well above normal. accelerating will make it go down, but will eventually go up again. turning the heater on will also make it go down. pretty sure it is the fan clutch or the radiator. anyone know a sure fire way tell which one???

 

What yr truck?
Is the fan belt missing? or coolant level low?

 

everything is up too par..... trying to let the engine heat up now to see if I'm able to stop the fan.

 

I can however have the radiator cap off at normal running temp. not seeing much movement in the water if any. should i see it moving?

 

That depends on if the coolant temperature is hotter than the thermostat opening temperature. At normal running temp the thermostat may stay closed until the temp rises.

 

I had the same problem a few months ago. It ended up being both, but I knew the fan clutch was bad because I could stop the fan with my bare hands while the truck was running. Try to CAREFULLY stop the fan clutch with a rag or something and if u succeed, change it. If the problem persists, change the radiator too (I did both).

 

Typically, truck overheating at highway speed but not at low speeds in town points to a radiator issue. If it only overheats at lower speeds in town, typically a fan issue.

 

X2 ,

Yep smart money says its a stat issue......

Also check your hoses for soft spots......

 

& I wouldn't recommend EVER putting any body part/foreign object into anything spinning on the motor when its running (even if you've been getting away with it) You don't have to in order to check the fan clutch, With engine OFF you can grasp the fan blades & check for side to side slop if you have an excess , fan probably on its way out, if you can't turn the fan at all with hands, the fan clutch is history, if you have relatively smooth resistance when turning the fan, the clutch is good & your problem is else where......

 

check your clutch fan with it off? my froze up but didnt cause overheating

x3 on stat
not flowing

 

Well if it froze up, like I said the clutch is history & can you imagine what would happen to your hands/arms if as suggested "try to stop the fan with your hands or use a rag" ?

Remember the fan is froze & the motor is running (but you don't know the fan is froze yet thats why you're testing it )

Now put your hand down there & try to stop it !!

Like I said do it with the engine off...

We already agree on the stat though..

 

My dad told me when I was a kid he knew a guy that was working on his car and his shirt got caught in the fan blade and sucked his arm in.( A metal fan blade too= No Arm.) No Joke either. Touching a fan blade at 1000 rpms may not be too safe.

 

i had a similar issue a while ago, I ended up having a bad thermostat and fan clutch, and for safe measure and because it was cheap, the radiator cap.

 

In my defense, I was wearing mechanix gloves when I did this and I found it out by accident. One thing i did notice when i changed the fan clutch is the air flow. There should be a lot of airflow coming from your engine when it's on. If there isn't... well, that's self explanatory.
I changed the thermostat too, it didn't help. It was the first thing i changed. Also, this whole highway/city driving idea isn't supported by my experiences. I had a bad fan clutch and a bad radiator and when i changed the fan clutch (i did this first) i still had overheating issues on and off the highway.

 

What about the sending unit giving a false reading?

 

You guys are all crazy!!! I never said i stopped it with my hand!!! I used my friends hand... I'm not that stupid..lol

 

lol