Recently my wife clobbered a large cow head on with our 1986 F150. Wrecked everything from the water pump to bumper. I replaced the water pump, the fan, the fan clutch, the radiator. Now, before cow collision happened I was having some overheating problems and my wife took the truck to the local garage and they replaced the fan clutch along with a new radiator and my wife said everything was working just fine and a week later she hit the cow. So..., here is my problem, after I installed all these new parts listed above and even "without" a thermostat installed this motor overheats. Can anyone out there tell me why and how it can overheat without a thermostat and all these parts being newly installed please? I am at a total loss and don't understand it. Thanks for any help or suggestions. Also I have good power and compression, no water in oil and visa-versa. I don't believe I have a blown head gasket or a cracked head. Ok, the needle on the gauge pegs as high as it can go and water and extremely hot steam shoots out of the overflow hose. Theres no bad sender here. Can't be a bad sender here trevorus. No twisted or collasped hoses. This is something simple but not obvious at least to me its not obvious. Well son-of-a-gun...if it wouldn't have happened to me I probably would not have believed it. I put the thermostat back in it and its doing perfect. I guess you was right about slowing the water down. Thanks for the help folks.

 

What is the temp running at, exactly? You may have a bad sender, or something of the sort.

 

There needs to be some restriction in the cooling system, or the water will flow through the radiator so fast that it does not have time to get the heat out of the water. Some guys will break the disc out of t-stat to make a restrictor. I do have one other thought. Does your truck have a serpentene belt? Rotation is opposite for serpentene and v-belt. Be sure the water pump and fan are the correct rotation for your engine.

 

I have been told that some engines has to have a thermostat to run at right temp. So I've gone back and put my thermostat back in. I haven't started the motor yet to check it but I will in a few hours. I'm using all the same belts that was orignally on the motor, they never appeared damaged in any way.

 

Only mentioned the belts to tell you that serpentine rotates opposite of v-belts. If you used used parts, or had a stupid parts guy, you could have wound up with the wrong rotation of the fan or water pump. Either of these could have adverse effects on the cooling system.