Thermostat: what is normal operation

[Keith_J]

Thermostats are proportionally opening devices, they throttle flow of coolant to maintain a certain temperature point. They work on the fact certain types of wax expand when melting, like most solid-liquid pairs act (other than water, ammonia etc). Melting wax forces the valve open via a simple hydraulic system. Over time, some of this hydraulic fluid escapes to the coolant, making the thermostat sluggish. but other times coolant is drawn into the hydraulic portion of the thermostat which causes the valve to open too soon or stay open. Still other times the valve is cocked in the carrier or otherwise impeded in closing.

Just because it passes a single point check doesn't mean it is serviceable. It must close, start to open at the stamped temperature and then fully open at a usually undesignated temperature, at least on the box.

 

[Bunkerbuilder]

Do there seem to be any nos radiators in the surplus market ?
I replaced a original Harrison 4 core with a shorter from tank to tank Modine and have had no problems with it since.

Still have the Harrison take out if anyone needs one.

 

[acesneights1]

I should note that the rad thickness is the same as the oem and that the two rows extend all the way back. So the core has the same effective thickness it's just flowing coolant across two longer skinnier tubes instead of 3.

I'm sure a mechanical engineer could do the math on the heat transfer

You may find this of interest. The aluminum 2 row cools better. I proved it.
http://www.dieselplace.com/forum/63...opper-vs-aluminum-rads-things-discovered.html

 

[acesneights1]

My CUCV's suck in extreme cold for heat. I have two they both barely put out enough heat to keep you from freezing to death. One has a new brass heater core, both have brand new GM factory tstats.Rads are blocked by cardboard in both. The heater system is a poor design. it draws fresh air from the cowl only and no way to draw cabin air. Couple that with a motor that doesn't really run hot anyway and no insulation, etc...Brr....

 

[Keith_J]

The heaters worked great in stock, new condition. Well, in the pickup versions, the 1009s have more to heat. I remember sub zero weather in upstate NY and we had to turn the temp control a bit to cool at times.

yes, they draw outside air for proper defog function. If they drew from inside air, humidity would increase to the dew point instantly. Even on vehicles with air conditioning, outside air is drawn in over the heater core.

 

[cucvrus]

The openly one of the m1009's that I have heat issues with is the one (Mule) that has a weak and leaking head gasket. Other then that they do run cool and the radiator cover is a must in this frigid weather. I have good heat in the Mule as long as I am driving at highway speed when I come to a stop it starts blowing cold air. And then switches back as soon as I get back up to speed.