Ok, another issue. I had the radiator boiled out and new fluids. Truck has always heated up when driving 75-80 on highway or pulling something (usually uphill). It does cool down and stay cool when not moving. So I got the truck hot popped the hood watched the fan/clutch as I shut it off. It came to a stop with the motor within 2 revolutions, the first time. Immediately tried it again and it spun down (about 8 sec to stop). Did this once more after driving for awhile same thing spun down slowly. Any ideas on what the prob could be here?

 

Your fan clutch is shot. I have never seen them spin down slowly, even on a brand new one. Either way, if its hot, there should be no slowly spinning down to stop. By hot, how hot do you mean?

 

Only have dummy gauge. It usually sits about 1/4 -1/3 of the way up. But when it gets hot it can get up to 1/2-3/4 of the way up. Last year my thermostat stuck and it climbed all the way up and popped a head gasket. So I know the guage works! I need to put a real gauge on, I know lol.

 

What gets me is just sitting in traffic it stays cool. If the cluch was going out or is out wouldn't I be overheating? Priced it both ways, $175 for clutch,$400 for radiator. Just don't want to end up buying both if only one is the problem.

 

It is spinning just enough at idle to keep it cool, doesnt take a whole lot. When you are running down the road at higher speeds and the engine is working hard, the fan appears to be spinning the same speed, and not engaging when it gets hot. Without the high temp lockup, you will get your symptoms.

On the other side of this though, when my radiator was bad, i would get the high temp at higher speeds as well.

Telltale sign is the fan lockup at high temps, if you are hitting 3/4 of the gauge, that is nearly 240 on mine from my estimates. The rad was boiled out, did they rod it out and clear any buildup. That buildup wont boil out, needs to be physically removed. If you had a working radiator, you could have a junk fan that wont lockup and still be fine so there is more to this than i originally thought

Might be a double failure. If your truck is middle of the gauge and the fan is spinning freely, the clutch is shot for sure. It should be stiff as hell, or locked up and make a very noticeable sound from under the hood.

 

Well when i picked it up he said chunks came out so I would guess he used a rod on it. He said also that be spent some time on it. When it is shut off and you spin the fan there is resistance don't know if that is a way of checking or not. I have only noticed the fan noise 3 times in the 3 years I have owned it. And that has been this past week. When I first take off, when the truck is warmed up.

 

so you hear it when you first take off?

 

Yes but, I have only heard it 3 times ever and that's been in the past week. Before that I have never heard it.

 

i would start with a real temp gauge.

 

Did it sound anything like this?

This is my new fan clutch from last summer, works great, and ALWAYS locked in when the engine is cold, only unlocks after you've been driving for a little while.


But defenently install a real gauge before! I love mine! Real easy to install to! Only challenge is finding a decent place to mount it in the cab.


YouTube - ‪What a Fully Locked in Fan Clutch Should Sound Like‬‏

 

How's that song go? "I'm getting hot and I have no clothes..." Something like that.

It sounds like a fan clutch or clogged radiator. Sometimes corrosion can block the passageways inside the radiator, so you may not be able to fix it by just doing a flush. You should hear the fan lockup and it is a distinct whooshing sound when you accelerate.

 

Diesel rads should never be rodded! The tubes have tiny dimples in them for more surface area and rodding them knocks the dimples off