Good morning! New member here and I have spent the last week digging up info on a heat issue I am trying to chase down. There has been lots of great information and I am appreciative of a place like this! My issue! A 2009 Cat 252b2 SN: SCP05099 purchased used this fall. Moving snow with it this winter, we have realized we have no heat. Fan works properly and pushes good air. We have flipped the cab up and verified no valves. We opened up the heater assembly and found the heater coil to be completely plugged with dirt and grass. We have cleaned all of this up and reassembled to the same end result. On the temperature control knob, the spindle can be spun freely by fingertip with no stop found with the plastic knob off. I am wondering if this valve is possibly stripped and stuck in the closed position not allowing me to adjust the temperature to the warm side. I do not have access to any other machines to test the theory. Unfortunately it is one very nice soldered system so replacement is not going to be easy! Are there any other ideas we can try? Thank you for any help!
Are you getting hot coolant as far as the heater.? Nobody plugged the lines or anything similar.? See attachment. Item #7 the control valve is likely to be your problem. No fresh air or recirc filters installed, or were they just overwhelmed.?
Thank you for the fast detailed response. We did not think to check the night we had it apart as the machine was cold. We will verify this afternoon! We looked for added valves first thing and did not find anything. intake air filter was missing. Found the cover under the seat. New filters installed!
That'll do it........ No worries. The fact that you posted the Serial Number in your OP makes finding information very simple.
The heater valve is just a butterfly, like a carburetor choke plate. I don't recall it spinning infinitely. On my 248B, the O-ring on the butterfly plate failed, causing the heat to not turn off.
Ok. The smaller diameter line coming off the thermostat headed to the heater in the cab does not get warm at all other than the first foot right after the thermostat (engine heat?) the lines behind the hydraulic reservoir and at the heater unit are cold to the touch. Without a temp gauge and considering the air temp has not been warmer than 20deg while working on this. Is it possible to have a bad thermostat? We found a replacement heater valve like heymccall posted (item #7 less additional copper tubing) and will have it as soon as the snail mail can get it here. $17 vs $149 for some excess copper pipe. Thank you all again for the help!
I have seen blown headgaskets cause no heat issues on those machines as well. If you've got a sight glass on the top of the rad that's empty and a recovery bottle that's overfull with coolant that's a symptom of a failed head gasket. If you have that happening, do a combustion gas test.
Sounds like the valve is not opening. Pull the knob off the valve and see if the stem on #7 is turning with a pliers. If it is turning, but no hot water is flowing, then you have to figure out why, maybe time to take off the hoses and see if you can blow air through them? or wait till the valve gets hers.
Fortunately, other than a small coolant drip somewhere in the system we have yet to find, the reservoir holds correct. When I pull the knob off and turn the stem, it spins freely with no stop. Definitely going to push some air through the heater coil once we have the system opened up.
Seen 2 machines like yours with no heat. Lifted rear rad perfectly level only to find 2 jugs of antifreeze missing. Do not trust the sight glass. If able to do, connect in and out of coolant temperature valve with small hose same size and if you have all kinds of heat throw valve in recycle. Couple simple things to check without money spent. Simon C
To be able to rule out a plugged heater rad, first bypass the coolant switch . If you get lots of heat coolant switch no good, but if still no heat bypass the coolant heater rad and if hose get hot right through you know the rad is internally plugged. If no heat through the bypassed hose better temperature gun outlet of thermostat hose in case thermostat is hung up somehow.. Lastly where you live is as cold as Alberta Canada. Have you blocked of any of the output side of radiator. Simon C