Hello all, need some help. I have a 2020 CAT 299D3 XE that I use primarily for land management/forestry. During the winter I use it to run a CAT Snow Blower. This winter, the heater has been giving me issues. It will at times blow hot/warm, but it will then blow cold with no warning. In can not figure out why it blows cold air even though the engine temp is up and It has been running for several hours. Any thoughts?
When the heater suddenly goes cold have you tried testing the heater hoses at the engine end to see whether or not they are hot.? If we start digging into technical stuff a Serial Number will be required.
Is the radiator full to the top , not just looking at the overflow bottle or sight glass. Have to ask as a few on this forum have been surprised to find out radiator was down 1 or more jugs of coolant. Usually a good place to start and then check on what Nige said with the heater hoses, plus a good old serial number. Follow Nige's advice and doubt if you will go wrong. Simon C