Just wanted to add that in my history of owning the 74 F100 it ALWAYS ran fairly warm at highway speeds. Think 215+ degrees with the fixed fan. Stop-n-go was fine, but hit 65+ mph and the temps would start creeping up.

Installed the infamous Lincoln Mark VIII electric fan and on low speed the temps were a steady 200 +/- 2 degrees.

HOWEVER, I found at 55 mph+ I could turn the fan OFF and still hold the same steady 200 and sometimes a little cooler!

So, I figure the factory fixed fan actually created a block or dam of air behind the radiator preventing the proper movement of air thru the radiator at higher speeds.

I am a big proponent of the MarkVIII electric fan, but I do not recommend installing the fan as a crutch to hide other problems.

From what I reading you do not have an overheating problem.

Josh

 

Only thing I will add to this discussion is block off any places where air will pass around or over the radiator instead of going thru it. This varies from vehicle to vehicle and I'm not familiar with your model. Adding an air dam at the top has helped a lot of early Bronco's I work on. They are notorious for high underhood temps.

 

[quote=Riderman;10667708]It's the Toyota Muffler. Dont take this the wrong way, but if all of the above statements are true, you would have no issues. By that I mean, someone may have made a mistake or something. I assume your fan and shroud assembly match. Your new radiator has never had coolant sealer in it (sealer plug's the aluminum cores fast!) Your cam timing gear is not retarded. Your ignition timing is not retarded. Your water pump actually pumps. (I bought two that had the impeller missing) Your Tstat is 195 degree's. Is the temp sending unit mounted in the head or block?

With all that, are you sure your temp guage is acurate? I've seen new sending unit's and guages be defective, Autometer, ect. While driving without a load, your truck should run it's coolest, not gain heat if everything is correct. Correct air flow, coolant flow, exhaust flow, timing is your friend. I'd buy a another mechanical temp guage with new sending unit and compare it to the "old" one. My 76 F250, 390, in last weeks 102 degree day with the AC running, did fine in traffic. If it was a 360 or 390 I'd say the head gasket's were reversed. I've seen that many times cause the exact same problem you describe on those engines, and even Volvo 4 cylinder engines. I'm not sure about the head gasket's on the 302's though.

I would use the above as a ck list.

 

First, punctuation and paragraphs will get more readers.

The 302 was a thinwall casting before it was punched 0.060 over. 0.060 over is pretty near max that I'ld go, it does lead to greater heat transfer from combustion to copolant with less iron between.

You can check to make sure that the short bypass hose from water pump back to kneck on intake is in fact, kinked! It needs a certain kink, and there should be a brass insert in the end of it to limit kink.

I didn't need to know all that other stuff.