I have the factory temperature guage. The clutch fan engages very little when it gets hot, doesn't stay on while it's hot. When warmed up the temperature hovers around the center of the guage during unloaded driving. I will check all those other things. ThxAre there bubbles in your coolant tank when it's running and up to temp? Is your upper radiator hose hard when its hot (it's supposed to be if radiator cap isnt sealing it wont keep coolant under pressure and will boil). Do you have a real gauge or the factory gauge? What does the inside of the radiator look like when looking through the radiator cap? Is your clutch fan functioning? If you hav a real gauge, without a load does the thermostat always maintain 180-190?
The temperature needle went past the normal range to the red and the overheating light came on and I could smell coolant so that's how I figured it was overheating.Saying it overheats pulling a load uphill doesn't mean a thing without knowing what temp your talking about.
The fan kicks in hi speed if you want to call it that, it kicks in at around 135*F to 140*F from the air thru the radiator that heats the coil spring in the fan clutch. Normally the fan will only cycle for 1 to 3 minutes to cool down.
Without a real gauge to indicate the head temp, your just guessing that it's overheating.
If someone installed other than a Motorcraft or IH T'stat, that could be a problem. IF it's a Chine made, they are prone to have the supports break off and not control the coolant flow correctly. See pic to see the three supports, thin metal strips to dome. Shown is the correct T'stat.
Hmmm maybe I should go ahead and get 2 new studs while I'm at it. It does have a lot of miles on it. ThxI use Three Bond 1184 for everything. It seals up within 10 minutes, well you need to let it tack up for 10 minutes, then mate surface and its ready for oil/coolant in 10 minutes. Be careful with the thermostat housing, soak it in Kano Kroil or something, i did and still broke one of the bolts, i was lucky enough through soaking after removal to get the broken stud out with vice grips
Silicone RTV used correctly is some of the best I've ever used. Never seize on the bolts will insure that you never have to use any penetrating oil again. Some penetrating oil, and a good sharp rap with a hammer and punch usually loosens the stubborn ones that don't have never seize. If I'm not mistaken, the thermostat will come with a square ring replacement, and won't require any sealant, just put it together. If it is a gasket, a thin layer of silicone on both sides, and let it dry for about 10 minutes then assemble.The temperature needle went past the normal range to the red and the overheating light came on and I could smell coolant so that's how I figured it was overheating.
The Tstat would probably be a good place to start. I'll get one from Ford parts and replace this one. Can you recommend a good sealant to use for this?
I can remember calling the weather strip adhesive "yellow death"What mechanics have used through the years for this and most all other applications is 3M Weatherstrip Adhesive on either the block or thermostat housing to hold the gasket in position, and a slight coating of the Permatex Aviation sealer (brown stuff) on the other side of the gasket. Actually if the surfaces are clean, no sealer is really needed, no reason why it should leak.
Unless someone has installed the wrong thermostat, it's a greater possibility your overheating problem is your fan clutch. When pulling hard at at least 2400 RPM or more, you should definitely hear your fan clutch lock up and roar when your gage needle gets to the upper area of the "hot" range. Mine has always done so, then the needle slowly creeps down to the lower "cooler" middle of the range while the fan is locked during long heavy pulls like going over the Continental Divide. And don't be led astray by this type of incorrect crap from another IDI site:
"once your speed is past 30-ish, the fan is useless anyway, as the wind over the radiator is more than a fan would pull over it. the fan does the most good in stop-and-go traffic, and when just stopped. but even climbing a steep hill at 35, there's plenty of airflow a fan isn't going to make a difference, but water flow sure will!"
The guy's obviously never towed much or definitely a flatlander who never saw a mountain.