Overheating 86' Toy Pickup

[opus]

For the life of me, I cant figure out why this thing gets hot. Changed thermostat, radiator flows well....any ideas?? It doesnt boil over but gets almost to the red line

[CougKid3030]

Have you flushed your radiator fluid recently? You could have some buildup or your fluid could be a little low... plus its a cheap and relativily easy way to see if thats all you need.

[opus]

Yeah, thats been done. I am thinking clutch fan now. Not sure how to be positive about it though.

[natenelsen]

The clutch fan you usually can just tell by hand if it is bad, give it a whirl and if it turns very freely then you may have a problem. Run the engine and goose the throttle, you should feel the air velocity pick up breifly before the clutch slips.

Most common problem to cause this on these trucks are radiator deposite buildup. These radiators will form a deposite on the inside witch does not restrict flow from top to bottom hose, but it does severly reduce the ability of the radiator to move heat because the tube are insulated from the inside. I have tried "rotting" these out in the truck to no good effect, I always wound up replacing the radiator. This is especially common on trucks that have been run on straight water for any length of time. Be forwarned, this can also cause damage to the head from corrosion. Be sure to use the proper mix of antifreeze . Before I would put in the new radiator, be sure the belts are tight, the t-stat is in correctly, and that the radiator is clean and not blocked by a trashbag or something similar.

Let us know how this goes.

Nate