My 96 F150 is my pride and joy. But I've been dealing with overheating issues. It calls for a 195 thermostat. I just put in a 160 as well as a new water pump. I've had radiator pulled and hot tanked plus patched a few pin holes in it. The clutch on fan is also in good working order. Plus the radiator cap is brand-new. So the only thing I've not done at this point is replace the hoses. It runs fine in the mornings. But in the heat of the day is the problem. Doesn't matter wether in town or highway. Also when I turn on my a/c it climbs even faster. Just did an oil change. I'm running Quake 10-40 high mileage plus add Lucas. So this is my dilemma, what do I do? Please help for this is my work/family vehicle.

 

I have tried all three thermostats (160,180,195) in my '96 with a 4.9. I found my truck runs best with the 195. It never got to operating temp with the 160, and the 180 was better but not consistent. I found that a 2 fin radiator did more to cool the truck but keeping it in running temperature then anything else. I also had replaced the fan clutch, water pump, hoses, and other misc. cooling parts. Doing a good flush will help.

There are others that made a 160 work, and others still that use an electric fan. Is your truck overheating or just running hot? If it's overheating, you may have the thermostat in backwards. If it's running hot, I would get a flush kit and do a complete flush first.

 

It'll run cooler than normal until the heat of the day. Then it gradually runs hotter and hotter until it's dang near red lining. The other day it hit the red line. So I shut it off and popped the hood. Pulled dip stick to see if oil was milky. It was so hot the oil on the dip stick just burned off almost immediately. I've flushed everything but the block. And the thermostat is in proper.

 

It's got the 302 and the radiator is the double not the single flow.

 

Is it hotest when your at a light or something? Does the temperature drop as you are moving? If so, then it's the fan clutch. Otherwise I would think you have a blockage or a stuck thermostat. Does the water seam to move when you open the cap at running temp?

 

Temp climbs the most when a/c is on. Turn a/c off and it slowly drops back down.

 

I've checked fan clutch and it does not spin freely so it's still in good working order.

 

A few days ago I took cap off and let it run for a while. Was able to purge some air out it. But problem persists.

 

I thought this seamed strange because mine spins with resistance so I looked it up in my Haynes manual.

3-3, part 4 Fan clutch check (vehicles so equipped)
1. With the engine cold (not running for at least one hour) and stopped, rotate fan by hand and feel motion. Fan should have some viscous drag and move smoothly through a full rotation. If the fan is not smooth, or either has no resistance or does not turn at all, replace the fan clutch.

That is a direct quote. There are other tests in the chapter also. So are you saying you feel resistance or it does not turn at all?

The a/c is a drag on the engine. You can expect it to raise the temperature if your cooling system is not working right.

You could also pull the thermostat back out and run it without one for a day or two to see if the truck still over heats. If it does, then you have a blockage somewhere or the water pump is faulty. Check to make sure everything is connected up right, like your heater core hoses.

 

Might want to check for head gasket issues or cracks. Check for oil/ coolant contamination, fumes in the coolant, and compression.