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Cat 247b3 no heat

chevyguy14

Member
Joined
Jun 26, 2017
Messages
16
Location
St. Cloud
Hi I’m having an issue where my 247b3 won’t blow heat. I took it out today and ran it to warm it up and then I lifted the cab and felt the two lines coming out of the heater core and they were both cold. So I traced them back to the engine and the hose that comes out of the regulator where the thermostat is was hot near the housing and then the line stays warm for about a foot and then it’s cold. Does this mean my thermostat is bad or some sensor? I haven’t had any issues with it overheating or anything though. Also the heat worked great in it last winter so not sure what’s going on. I would appreciate any help. Also the serial number is TSL01509 if that helps. Thanks
 

chevyguy14

Member
Joined
Jun 26, 2017
Messages
16
Location
St. Cloud
Coolant level correct?
Fan belt present?
Water pump actually turning?
Heater knob not stripped?
The coolant level is good, it’s about 1/2 on the overflow tank and I have a pencil line on the tank to mark the level when it’s cold and it’s still at that level and I haven’t had to add any coolant all year. The fan belt is good I had a new one put on this spring and it’s tight. For the heater knob in cab it does feel like it working but there’s no way for me to tell for sure with out taking off the hose and looking inside to visually see if the valve is turning. As for the water pump I believe it’s working, the two main radiator hoses both get hot when running so I think that would be a good indicator that the water pump is working. I’m not a pro though so correct me if I’m wrong on any of my reasoning with these or if there’s something else I should check?
 

chevyguy14

Member
Joined
Jun 26, 2017
Messages
16
Location
St. Cloud
See the link I posted above. There is an electrically-operated valve that controls the heat on those machines.
I did look at that but on my schematic it is #24Screenshot 2020-12-19 120120.png
which is part number 231-8126

akhsbckabsk.jpg which appears to be a manual valve that connects to the control knob in the cab
 

chevyguy14

Member
Joined
Jun 26, 2017
Messages
16
Location
St. Cloud
Mechanical valves fail as well. Movement of the stem doesn’t always translate into movement of the actual flap (for lack of a more technical term)
Ya that’s true but even if the mechanical valve has failed and the flap is stuck in the closed position wouldn’t the heater core inlet line at least be hot up until it reaches that valve? The problem I’m having is where the inlet line gets cold after like a foot of leaving the thermostat housing which makes me think that the problem is before it even gets to the that valve and heater core.
 

chevyguy14

Member
Joined
Jun 26, 2017
Messages
16
Location
St. Cloud
Ok that does makes sense. I will have to do some digging then into the valve and I’ll report back what I find. Thank you both
 
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chevyguy14

Member
Joined
Jun 26, 2017
Messages
16
Location
St. Cloud
Finally got around to looking into it and sure enough it was the mixer valve. The knob turned but the valve inside was stuck closed. I ordered a new one and installed it and now I have heat again. I really appreciate the help, thanks.
 

Simon C

Senior Member
Joined
Jul 1, 2015
Messages
663
Location
Rocky Mountain House , AB., Canada
Occupation
Heavy Equipment Mechanic
The coolant level is good, it’s about 1/2 on the overflow tank and I have a pencil line on the tank to mark the level when it’s cold and it’s still at that level and I haven’t had to add any coolant all year. The fan belt is good I had a new one put on this spring and it’s tight. For the heater knob in cab it does feel like it working but there’s no way for me to tell for sure with out taking off the hose and looking inside to visually see if the valve is turning. As for the water pump I believe it’s working, the two main radiator hoses both get hot when running so I think that would be a good indicator that the water pump is working. I’m not a pro though so correct me if I’m wrong on any of my reasoning with these or if there’s something else I should check?
Always good to put the radiator level and check the level of antifreeze with the cap off. Because if you ever get a small leak in the system, when it cools and tries to suck back from the reservoir it will suck in air from outside instead sometimes and your coolant level overflow tank wont come down. Many folks have been horrified to look down into a rad and find it half empty with the overflow tank still full.. Hope this helps for if it ever happens to you. Simon
 
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