JC, was the truck running cool and then began overheating or is it new to you and it overheats?
Is there any chance the belts were slipping? Does the fan hub turn freely? When you look through the radiator hose fittings, particularly the lower one do you see any scale or crud? If the belts were tight, the water pump turns freely and the pump does not have any signs of leaking there are still other thing to check.
Was there any oil in the coolant you drained? Is there any visible scale or crud in the engine as observed through the hose fittings? Does the radiator have any dirt, crud or say, 4 coats of paint on it? If you look into the hoses is the inner liner of the hose intact? If you squeeze them while looking into them does anything look out of place? Is there any white smoke in the exhaust? Have you been loosing or gaining coolant? Is there any sign of coolant in the crankcase oil?
Leaving the cooling syasem for a moment, When some trucks had turbos added the job was done "down and dirty". The fuel injection timing should have been changed from 25 degrees before top dead center (BTDC) to 20 degrees BTDC. The timing marks will never be easier to see than when the radiator is out. I'd check the timing. Heck, when we put a new radiator in our M35A2C we checked it just for giggles.
Good luck
Lance
I've had the truck since Dec. 30th but only got plates for it this week. It made the 50-mile trip from Frankfort to my house at normal temp, back in Dec. But since I've started driving it last week, I've noticed it running on the high side of the temp gauge. If I've run it for a while, I'm also noticing some coolant spitting out of the radiator cap after shut down. Not a lot, and no big steam spray--just a few drops.
No oil in the coolant or coolant in the oil, that I can see.
I was surprised how clean it looked. There is a very fine / thin amount of sediment in some of the inlets but nothing caked or major to my eye.
Everything was tight with the belts. I guess to see if the water pump turns freely, I need to remove the alt belts? Otherwise I can't turn it without turning the crank shaft.
The thing I thought was a little odd: I got maybe 7 gallons of coolant out. Now, I didn't open the block drain like it says in the TM (yet) but I've got the radiator totally off, upper and lower hoses removed as well. I'm sure there's some in the block but I wonder how much? Capacity is like 37 quarts and I've recovered maybe 28-30 at the most...
