Posted by Clint Dixon [172.68.58.86] on Wednesday, May 23, 2018 at 19:25:25 :
So here is what I have done so far:
1) Replaced head gasket. Retorqued head once warm.
2) Cleaned carbon out of combustion chambers
3) Checked 160 degree thermostat and verified that it is starting to open at about 165 degrees and is fully open at 185 degrees.
4) Verified that the dash gauge reflects these numbers. Temperature never rises above 165 degrees at idle.
So what did I do? I took the advice of
5) Verified that timing is advanced to approximately 4 to 6 degrees BTDC.
6) Verified that centrifugal advance works smoothly and evenly and levels out at about 12 to 15 degrees at approximately 2,000 RPM.
6) Checked vacuum hose to windshield wipers. No vacuum leaks in that system.
7) Vacuum at manifold reads a steady 20 at idle.
Took truck out for a drive on the governor (about 55 mph) two days ago when the temperature was about 75 degrees. I have straight water in it now as I lose some antifreeze each time I drain the system. Took it out again this after noon with temperature in the low 80's. Each trip was 4 miles one way with many hills. Same speed both trips.
Result - engine temperature never got above about 185 degrees either time. In a couple of days the forecast is for us to have high 80 degree temperatures, with a possibility of it reaching 90.
So what did I do that may have made a difference? I took the advice of MikeinMissionViejo. I checked the fan belt. Seems it WAS somewhat loose. If this is what the problem has been all along, it makes sense. This all started about the time I installed a new belt, and I must have forgotten to go back and tighten it after it had a chance to work in and stretch. In my defense, it is hard to check the tension on the belt on this truck. On the driver's side, I have a Monarch hydraulic pump sitting up on the generator in the way - belt driven off an additional pulley on the generator. On the passenger's side, I have a King-Seeley governor in the way - belt driven off an additional pulley on the water pump.
I will take it on a few more short trips as the weather gets hotter. We'll see if it still runs cool before tearing into the water pump and distribution tube. I'll keep everyone posted.
Right now I am feeling about as dumb as a box of rocks! Thanks for everyone's continued support and suggestions.
Junior
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