M925A2 ( M939A2 Series ) Engine Coolant Cab Heater Performance

[Wildchild467]

Good Morning my Steel Soldier Friends,

I have a friend with a M925A2 and the performance of his heater does not seem to be as good as the one in my M35A2. I know they are somewhat different animals with cam volume, engine spec and cab floor insulation... but they are the same heater core I believe. It is about 50 degrees in the mornings lately and he is not happy with the performance of his heater. Does anybody else have any reviews/opinions of the engine coolant cab heaters for the M939A2 series trucks? Do they work good for you or do you recommend changing it to a fuel fired cab heater? I know the fuel fired heaters offer instant heat but can be temperamental sometimes. Thank you for your input.

 

[oboyjohn]

Has the heater core ever been flushed out? Up here in Canada, we would disconnect the supply and return lines and reverse flush them until the water runs clean. My 2 cents.

 

[Wildchild467]

It has not been flushed that I am aware of.

 

[162tcat]

I have a soft top thats always cold but my hard top seems to hold the heat in better. I'd start with flushing the heater core as mentioned above.

 

[wheelspinner]

My 8.3 is VERY SLOW to warm up. It will take awhile to throw real heat like my A0 did. It took almost a year to work it hard enough for the fan to come on. The cooling system in that engine combo is huge.

 

[Carlo]

Has the heater core ever been flushed out? Up here in Canada, we would disconnect the supply and return lines and reverse flush them until the water runs clean. My 2 cents.

Bravo! I did the same thing and the difference was day and night.

 

[Gunzy]

Are the water valves on the engine at the heater hoses open?

 

[Wildchild467]

Valves are open on the engine. I guess I will pull the heater core and flush it out. Cant spoil a rotten egg!

 

[srodocker]

Didnt think of flushing it out....Will have to try it.

 

[Karl kostman]

I have a 925A1 and the first thing I will say is the cooling system on these trucks is very large and it takes a lot or some very HOT weather to ever get the fan to run and I could absolutely say that just driving down the road at 50 degrees with no load on the motor the fan will likely never run. The first thing I would do is like was said before Flush the heater core to make sure that you have good coolant flow through it, as long as the valves on the engine are open that part should be done. The next thing is to start blocking the amount of radiator that is open to air flow while in operation, this will help to get the engine warmer faster BUT and I do mean BUT you will have to monitor much more closely the engine temperature gauge, if its getting warmer outside or your working the truck harder the temp is going to rise to much and could cause problems. I live in ND but dont drive my trucks after the snow flies because of salt on the roads but till then I have driven my 5 ton down to about 10 degrees and the heater kept is comfortable inside the cab, and my cab is a hard top.
Good luck
KK

 

[Ford Mechanic]

Does anyone know if there is a common part number for a replacementry blower motor? Mine has died and I was trying to find a napa replacement.

 

[74M35A2]

There is. You should be able to locate it with a forum search, I did when I replaced mine with the NAPA unit. Fit and worked perfect. Only difference is the motor ground wire is external on the NAPA one, so you simply tuck it under a mounting fastener.

 

[Ford Mechanic]

There is. You should be able to locate it with a forum search, I did when I replaced mine with the NAPA unit. Fit and worked perfect. Only difference is the motor ground wire is external on the NAPA one, so you simply tuck it under a mounting fastener.

I looked in the common parts sticky at the top and tried searching for it, no luck. I know i've seen it just can't remember where. Got any hints for keywords? Searched "blower motor" and "heater fan". I seem to find every thread that has nothing to do with what I'm looking for but this one..... little help or direction please?

 

[allpredatorcalls]

Napa P/N 655-1320 http://www.steelsoldiers.com/showthread.php?127737-M923A2-cab-heater-blower-motor

 

[jarhead1086]

My heater is in great shape, but I am looking to possible remove it and replace it with something that fits better as I juggle things around fitting a turbo in this winter. As others have stated, I don't drive mine on the salted winter roads, but heat is still absolutely necessary. I am not sure what the BTU is on the stock heater? I will have a clean no rust heater and motor for somebody if I swap out. Here is a nice unit from Sports Import Ltd for $240. Thinking you could mount the coils on the firewall under the passenger dash and leave the motor and hook ups hanging out in the engine well. Less heat loss and a space savings in the engine well. If I add an intercooler I won't be able to move my surge tank to the driver side.

Specifications

16,000 Btu/hr @ 180°F
220 CFM
4 Amps @ 13VDC
2 Amps @ 24VDC
3 Speed Resistor for variable fan speeds
Multiple mounting configurations

Dimensions

6.3"T x 9.5"W x 7.1"Deep Available with 5/8" Fittings Rear or Floor exits

 

[wheelspinner]

Here is what everyone is missing. The engines do not warm up quickly or well in cooler weather. A front cover is absolutely necessary to bring temps up, doesn't matter how many BTUs your new heater has available, when the BTUs are going out the front rad, you don't get it in the cab.

 

[Ford Mechanic]

Napa P/N 655-1320 http://www.steelsoldiers.com/showthread.php?127737-M923A2-cab-heater-blower-motor

That was the exact thread I was looking for but couldn't find it! Much appreciated!