Posted by Clint Dixon [172.69.58.248] on Sunday, May 21, 2023 at 15:11:16 :
Those who have been on this forum for several years probably remember in May 2018, I started tearing into my '51 B3PW to find out why it had appeared to be running hot for a couple of years during the hot summers. The threads on the subject started on Forum 539 and can be viewed at the Phil's Archive link available above.
So basically I replaced everything I could with new including the radiator, water pump, head gasket, hoses, and thermostat. All of these were checked before installation to assure they were good. I also checked the distribution tube and it appeared to be new as I had apparently replaced it some 17 or 18 years earlier. I checked the timing, belt tension, mechanical advance in the distributor. Replaced plugs, cleaned the combustion chambers, checked plugs to assure the truck was not running lean. The only think I have that I did not install is a NOS temperature gauge and sending unit. I am reluctant to do so as it is going to be a pain to thread it under the dash and through the firewall without bending the tubing.
So I get the truck all ready for the upcoming season a few weeks ago and head out on the first drive. Over the past 6 or 7 years, the temperature gauge has been reading about 200 degrees. This came on all of a sudden back then on a 100 mile trip home on a very hot day.
Well, on this short trip a few days ago, the temperature gauge finally reached 212 for the first time, and it was not an overly hot day.
Today it is 70 degrees with a very slight breeze. I took the truck out not on the customary "country mile" but on the country 4-mile. This is a route that takes me 4-miles north, 4 west, 4 south, and 4 back east to home again. 16 miles total on paved roads. Yep. The temperature gauge reached almost to the 212 mark.
I got out my elcheepo infrared thermoeter and started checking (again). After the drive at an idle at the shop door, the temperature was not going down any. I was getting readings of about 100 degrees in the lower radiator tank. 180 degrees in the engine block on the driver's side. About 200 to 220 on the head across most of the top. About 300 on the head above the exhaust manifold. And about 200 to 220 on the outlet around the thermostat. About 180 on the water pump.
So then, I took my '47 out on the same trip at the same speed. Back at the shop I again get my elcheepo infrared thermometer out. Now this Made in Red China laser unit that did not cost me much at all. So I know it is probably not very accurate, but I was just looking for a comparison between the two trucks. My '51 in reading between 200 and 212 degrees now but I have never had it boil over and it never seems to be low on coolant.
My '47 never reads over 180 degrees (knock on wood).
The results showed that the '47 temperatures while idling after the drive, and taken in the same places on the engine and components, were no more than 10 degrees cooler than the readings I got on the '51.
I guess I had better break down and install that NOS temperature sender and gauge. But first, I think I will test the existing one in a pan of water on the stove with a food thermometer, as well as test the NOS one for comparison.
Ideas?
Junior
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