ok heres what iv tried. changed the thermostat. no good changed the water pump 2 times one was bad. tookt he stat out no good. flushed the radator still no good? why does it still overheat?? thas 2 truck has 2 fans 1elect 1 on the pump. i even tried leaving the clutch fan off and let the elect fan cool it. it comes on but still overheats?

 

What's the oil and coolant look like? You may have a bad head gasket. If it overheated, even once, there's a good chance.

Is the radiator flowing water? Can you feel a difference in temp between the upper and lower hoses?

What happens if you turn the heater on HIGH when you're overheating? Does the temp drop?

 

the oil is real clean and the coolant is new the top and bottom hoses are the same Hot.. the waters not flowing its standing still and if i leave the cap off it overflows.i thought about the head gasket. how do you tell? I have no leaks and the motor runs real strong. Wouldnt water come out the tail pipe if the gasket was blown? when i put the heat on it blows blazing hot. The temp drops alittle but not much.

 

Heater core blocked?

Go to autoparts store. Rent tool that tests for exhaust gasses in coolant.

 

One way to tell is to test for exhaust gases at the radiator filler neck.

When did this start? Did you do any maintenance to it just before?

If the heat blows hot you are moving water. If you weren't, it would be ambient.

Are you positive the thermostat is in correctly? What brand/temp did you get? How about the belt routing? Is it correct?

 

The thermostat must be functioning else it wouldnt be moving water and hoses would have a tenp difference. He also says he ran it with no stat.

Op, did u burp the system by running it with cap off till fans are kicking in? Really does sound like head gasket. Maybe a very bad radiator?

 

It could be a bad radiator.

Is the clutch fan back on? When are you overheating? At idle, all the time, on the highway, etc? The clutch fan should be roaring when you get hot.

The hoses should have a temp difference if the radiator is working. The outlet should be cooler than the inlet. It doesn't sound like he is moving water through the radiator - at least much of it, since he doesn't see any movement.

Here's how you fill and "burp" the 4.7.

REFILLING 4.7L ENGINE
CAUTION: Failure to follow the procedure outlined below, can result in engine overheating conditions and severe damage to engine.
(1) Tighten the radiator draincock and the cylinder block drain plug(s) (if removed).
(2) Fill system using a 50/50 mixture of ethylene glycol antifreeze and low mineral content water.
(3) Fill coolant reservoir to FULL mark.
(4) Install radiator cap and reservoir cap.
(5) Start engine and run at 3000 RPM for 10 seconds.
(6) Shut engine off.
(7) Remove radiator cap.
(8) Fill radiator to full level.
(9) Install the radiator cap.

 

it gets hot with or with out the thermostat in. but with it in i have heat take it out and no heat. also gets hot with or with out the clutch fan on. but the electric fan does come on.( it has 2 fans. I saw a guy take his clutch fan off and ran just the electric fan and had no problem. my thermostat is in the bottom hose it goes spring toward engine right? point end out toward hose? guess ill rent a test kit if its not the gasket then its the rad right?

 

Spring towards engine is correct.

Whether you can take the clutch fan off depends upon your driving style. Low speed driving, lots of idling, or towing a trailer and you'll get hot. Driving down the highway, you shouldn't have any issues.

You can get a radiator flow tested.

How are the hoses too? They can "collapse" and restrict circulation - especially if they are getting old. You can't tell from the outside the condition of the inside.