tonyjklh

I have a 1993 F150 4x4 with the 5.8L. The engine has an upgraded cam and a MAF conversion (for future mods). Anyways I have had overheating issues for the 4 years I've had the truck. First I replaced the fan clutch with one from AutoZone and it didn't really help. I also put in a new radiator (2 row) which did not help. Later I upgraded the clutch to a Hayden severe duty clutch and no more overheating.
Now some background on the overheating. It would happen easily driving around town during the summer (95-105 degree, no towing) and the coolant would boil immediately after turning off the truck. Overheating on the highway would also happen up a decent grade while towing 3000-4000 pounds. The entire cooling system has been rebuilt and flushed (several times). The severe duty clutch solved the overheating, but that came at a big cost.
Why don't I just stick with the severe duty clutch? Because it honestly feels like a 50hp draw on the engine. With that clutch the truck feels like it has a 4 banger under the hood. Mileage also dropped by 4-5 mpg with that clutch. This clutch really shouldn't be necessary to keep the engine cool. And the truck being about as loud as an air boat isn't great either. I tried a Taurus e-fan last summer, knowing that many on the forum had good luck with it. That didn't work out well at all. Without towing it was fine, but towing in town just couldn't happen. Towing down the highway the truck also ran hotter than it normally did with the Taurus fan. Also, as soon as I exited the freeway the temps would climb rapidly, even with the engine doing little work.
I'm guessing I probably have a head gasket problem. I'm going to test for exhaust gas in the cooling system soon.
Does anyone have any other ideas why my truck runs so darn hot? Also, are cracked heads common on these engines? I don't want to do head gaskets and find out I have a cracked head.
As another note, the overheating problem existed before the MAF conversion also. So that conversion is not the source of the problem.

SaltEater

Something somwhere is adding more heat load than the pump/rad/fan can handle. Any oil starvation or blowby issues? Exhaust leaks? You've verified the direction of flow with the pump/hoses and also that the fan spins the correct direction? The fan shrouding is in good condition, forces all air to pass through the rad?

When you rebuilt the system did you put everything back the way it was with new parts, or did you follow a manual? Which parts did you replace when you rebuilt it? Rad and cap, pump, fan, belt, thermostat, temp sensors?

Just checked your post history, are you still running the e4od or did you swap to a manual? If you're still running an auto and had a burnt out torque converter, could that add significant heat load to the rad via the trans cooler? Would also explain why a new converter solves the issue.

A cam on it's own shouldn't add to much heat load to the cooling system, unless it's running lean af. I'm not sure how it would effect the total cooling system, but the headgaskets control direction of conrtol flow through the heads, if they were installed wrong by the PO it could be superheating the back 3 cylinders on either head (or both), but then you'd have worse problems than coolant boiling.

dodgeman1

Modern radiators are so much smaller and more efficient than the old days but three row radiators use to be the bigger radiators on older cars. Also if you are running a lot of timing, that makes it run hotter. I'm not real familiar with your engine to know if you can even set the timing or not.