Questions about the fan clutch on a 2000 XLT 5.0

[JT624]

I've been having a lot of overheating issues lately. Initially I had a leaking radiator, I knew of it for a long time but let it go and just kept topping up as needed. It wasn't a fast leak but I knew about it. A couple of months ago my girl had the truck on the highway and it gave out, completely overheated (I know. the phone call you never want to get).

After a tow home I changed the radiator the radiator cap, and t-stat and flushed the heater core and block with water from the hose for a good 45 minutes or more (I didn't use any special flush as it was constantly being topped up it ran clear almost immediately). Anyhow, after all of this I am having the dreaded overheating back for a second visit. Now it overheats as soon as it warms up, mostly under load or if I revv the motor in the driveway (I've been doing that while looking for leaks).

So long story short: I believe my fan clutch is no good. It has the same loose frewheel to it whether hot or cold. My question is: How much does the fan speed really affect the temp (gauge)? I'd hate to change it if I'm overlooking something but apart from the water pump or a dead mouse pluggin a line (neither seem to be the issue) I don't see what else it could be.

Thanks in advance for any opinions you folks can offer.

 

[shadowless127]

When you flushed the system with the hose, was everything flowing normally?

 

[Joe Dirt]

When you spin it by hand, how far does it spin?

 

[JT624]

If I spin it hard it goes about one full revolution.

 

[Joe Dirt]

Iffy... If the engine is warm, start the engine, then turn off the engine and see if the fan keeps spinning. If it does, your fan clutch is bad...

 

[JT624]

It feels no different at temperature, same amount of spin. I have a feeling it's bad.

 

[Joe Dirt]

Probably- any junkyards around? Or, even the fan clutch aftermarket isn't bad...

 

[shadowless127]

To me this sounds like a good excuse to do an e-fan conversion

 

[JT624]

I was pricing fans and clutches, it might be worth the time to just go for it..

 

[Joe Dirt]

if it's already out...

 

[haphop]

I would replace the thermostat. It may have stuck closed.

 

[JT624]

This one is a month old and I've put 2 in it this past year. Not counting the one I replaced initially which makes 3 in one year. This problem has been going for a long time, I think the overheating is what pressurized and blew that tank eventually on the old radiator. I'll update this post when I put in the new fan but I'm feeling confident now that it's going to cure this issue. There's basically no other items left to change.