Posted by Joel on Sunday, November 13, 2005 at 7:01PM :
My 1966 WM300 251 engine was rebuilt last year at that time i had the radiator cleaned out and checked for leaks the radiator shop owner said all was well when finished. when the motor was re-installed with the radiator i installed new old stock radiator cap from V.P. and everything worked well. My temp. reading always stayed in the normal range the neadle on the temp. gage would stop right at the letter H in the word HEAT on the temp gage. It has taken me another year after the motor was rebuilt to finish the body work and put the truck on the road. So for about a year the only time the truck ran was just long enough to pull the truck in and out of the garage and around the yard. Now I have put around 150 miles on the truck and my temp. gage in the last few trips has worked its way across the dial to where it stays on the letter A and the word HEAT on the dial. The radiator has never boiled over as an obviouse sign of overheating but i felt the temp. gage reading had to be abnormal. so i changed out the thermastat with a 160 degree therm. this made not difference at all. I drove my powerwagon to the firestation the otherday and used our thermal heat gun to take the following readings... at the back of the head at the sending unit 174 degrees. Near the water outlet where the therm is housed 164 degrees. At the top of the radiator tank 154 degrees. At the top of the radiator core 144 degrees. At the bottom of the radiator 114 degrees. I was told by a couple of mechanic that there should be more than a 15 degree difference in temp. between the top and bottom of the radiator. So here are the possible problems they suggested 1. plugged radiator 2. bad water pump 3. bad sending unit 4. nothing is wrong at all. since this is the only powerwagon i have owned help me out for what is normal for these trucks and which direction i should take first. Thanks, Joel.
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