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I feel like my Jeep won't get up to temp. I posted elsewhere and was told it was nothing to be concerned about.. So per an IR thermometer at the t-stat housing, the coolant will get up to 170-175 degrees after 20-30 mins of mixed driving. -The heat works great and both heater hoses are hot. -The upper radiator hose gets warm-hot. -The radiator is reading 100-130 degrees via IR thermometer. The radiator cap does not get hot. It was 43 degrees out when I did this drive. 88 Comanche with open cooling system, 4.0l. Flushed the (already pretty clean and under 2yr old) cooling system 2 times, once with VC9 and the other dish detergent, with no heater core in the loop. Then replaced heater core, and put in a new 195 degree Stant thermostat. Coolant is roughly a 50-50 mix and all new. I did all this and now it won't get up to temp. Before this the Jeep always ran perfectly at 205/210 and never had an overheating issue. Any ideas?

Hi, Got a 92 MJ 4.0. Just replaced the water pump, thermostat (195 deg), coolant, and blower motor... Used to be that I got really hot air coming outta my heater...now it's just luke warm at best. The blower motor was one that had the vent hole (in the motor casing) in the wrong place for me to hook it back up properly, so i left the rubber hose off. Could this be causing me the cold-air situation? ANother thing is that the jeep is running noticeably cooler (like propably 20 deg) according to the dash thermometer...could it be that it's just not warming up all the way for the 195 deg thermostat to open up...? Does that make sense? Thanks!

Okay so here in Michigan the temps have been close or below zero for most of the month. My issue is that sometimes my heat will not work. What happens is when the truck warms up fine to operating temperature, I turn on the heat and cold air blows out. What I have done to try and fix this is back flush the heater core. Which did help because when the heat does work the air is a lot hotter than before. There was quite a bit of crud in there. What I assume now is that: 1) I am not getting enough vaccum to open the main air flow gate which either lets ambient air or heated air through. 2) The main gate is frozen somehow 3) vaccum leak somewhere...? After the temperatures outside increase a little and the inside of the truck warms up a bit, the heat works fine. It is only when the mornings are arctic cold. Am I right with my assumtions or is there anything else I should check?