New to me machine. 2004 cat 322cl S/n HEK00405 I took the cover off behind the seat to locate the heater core hoses. They are both hot to the touch. Probably 120 degrees. The air blower will blow hard. But it will not produce any hot air in the cab. Please help! Its cold!
Heater core plugged? Have seen that when stop leak is used in the cooling system
Is there any airflow coming out of the vents?
Find the valve to open the flow?
If it was clogged, both the inflow and the outflow hoses wouldnt be hot right?
The two cab heater valves are under the alternator. I assume they are open because the hoses at the heater core in the cab are 120 degrees.
If the cooling system was at normal operating temperature the engine should be around 200 degrees. I wonder why there is such a difference between the engine and the heater core.?
They may be 200 degrees. I just touched them with my fingers and they are both too hot to touch for me.
"The air blower will blow hard" tells me the heater core is blocked with something. Got a mouse nest in the housing? Without a diagram it's just guessing, but if you hear the fan and no air comes out something is in the way. Or does it have flaps to direct the flow, does it have AC that uses the same ducts? Joe H
The heater core on that machine is live (no water valve). Heat is regulated by #19 actuator swinging door #21 to restrict or enhance flow of air thru the heater core. Does actuator #19 turn in response to temperature change requests? Have you checked for HVAC fault codes? Pic of HVAC control panel will help. I had 330B or C's (my memory is fuzzy) whereupon condensate would form in the actuator and result in the blend door shearing it's pin off. Service magazine provided an upgraded blend door, IIRC.
If the inflow hose and outflow hose are hot, doesn’t that say that the heater core is not blocked?
With that style, all the debris gets stopped at the evaporator. Never had a dirty heater core on one, yet. But, technically, a rodent "could" get in via the blower side. Are there HVAC codes?
Very interesting, how do you check the door actuator? This is what my controller looks like. Very confusing in my opinion.
My CAT 320C has 3 dampers/servo motors that direct air flow. They were stuck and generating Error codes. The guys here helped me track it down. I lubed them and made them move. No immediate help...let them sit overnight, tried again. Lube must have kicked in. They started working OK after that.
cor21e "If the inflow hose and outflow hose are hot, doesn’t that say that the heater core is not blocked?" No, it indicates no airflow through the core. The outlet will be cooler if air is cooling it, making hot air which is what it should be doing. No air flowing through the core to cool the hot water going in = hot water comes out.
I bet you that is it. Thank you!
Good logic. I like it! But if heater core was clogged from “stop-leak additive” then one hose wouldnt be as hot as the other when there is no airflow.
Is the heat actuator in the cab cable or electrically operated?
Electric I believe
It's electrical. There is a way to see if the hvac has codes. I don't recall the sequence. If you remove the shelf behind seat, you can see if actuator responds to you turning temperature knob.
I have the hvac shelf removed. Today I am taking the actuators out.
I was always under the assumption that if both hoses were hot, there was no flow, as it was just feed back from outlet hose. Depends on when you check it I suppose but sometimes depending on where the heater core is, you can feel the lines pulsing when you squeeze the hoses.
If the airflow thru the heater core is blocked, via the blend door, it will shed no heat (both hoses will be hot to the touch). With the shelf out, machine running for at least a minute, select full heat, then select full cold. If the actuator responds both ways, it's possible that the blend door shaft has broken. If so, the door and the actuator should be replaced. As an aside, you can check for HVAC codes if someone can dig up the sequence for that control panel.
I took the actuator off. The male door pin had sunk down and was not engaged in the female actuator hole. The actuator is working perfectly.
Does that mean you fixed the problem? Is the actuator a damper?
The actuator is an electric motor with a square female hole in it. It spins the male square rod that opens and closes a door. The heat started working. But not very well. Probably clogged with dust??? Need to start taking it all apart.
I think that the door shaft is somehow broken. It wasnt in the actuator. It dropped down an inch
I think that the door shaft is somehow broken. It wasnt in the actuator. It dropped down an inch
Sounds like you are on a good path anyway. Keep us posted.
The flapper door was broken off the hinge. Had to take the entire air conditioner out to replace bottom bolt to the flap. Also one of the gear movers for the flaps was broken. Replaced that. Lubed everything up. And worked fine. Also. The heater core had an incredible amount of dust in it. I dont think anyone ever put an air filter in the machine. Washed it out with the hose.