M813 Heater Questions

[R Racing]

Ok After doing several searches I haven't really found my answers. I have a Coolant heater in my M813 on a 30 degree day I may be lucky to see mid 50s in the cab ( I know these trucks are leaky and have no insulation ) So I'm wondering if thats the best I can expect ? also how hard of a job is it to swap out the coolant unit for a artic fuel unit ?

 

[cbvet]

Is the engine getting up to temperature? My 813 is very slow warming up. By blocking the radiator it's a little quicker.
Is the fan running?
When I have time, I plan to relocate the heater under the dash as in my Deuces. Works MUCH better that way.
But if the engine isn't warming up, you still won't get heat.

 

[R Racing]

The truck seems to take forever to warm up. I have blocked the radiator with cardboard but even then it just will hit 190 on the gauge if im lucky. I didn't know if moving 1 of the hoses to the water pump would add heat to the unit ? Fan runs all the time .Is it on a air clutch like the m920 ? The fan heater runs on high only.

 

[73m819]

no, the 813 fan is belt drive

 

[cbvet]

Sorry R,
I was referring to the heater fan.
At 190 you ought to get plenty of heat.
Are the valves that supply hot water to the heater & return it to the engine open? You screw the stem out to open. There may be two, or just one.
Does coolant come out of the heater bleed valve? It should. Be careful. It will come out with some pressure if the cooling system is tight.
In the past, I've seen heater cores get plugged-up. Easy job to just remove the hoses & flush the heater core. Run water through both directions. Remember the core is not made to withstand more than about 15 PSI.

 

[R Racing]

Sorry I'm running on no sleep , lol. Yes I double checked and both valves are screwed out. It doesnt mean there not clogged with goop. I may have a chance this weekend to pull them out if the steering gearbox swap goes easy. all good info so far.