Heater's not putting out like it used to :)


New member
09 Jeep Wrangler Unlimited X with 95K used to have the most amazing heater. I always take it for early morning races so I can get my feet super warm before I brave the cold. I also noticed I used to have really cold air coming in the glove box. Now that the heater takes longer to get warm and never gets as warm, I also noticed that the glove box doesn't feel cold anymore. Should I replace thermostat first and if so what degree do you recommend? I need to flush the antifreeze anyway so I'm not opposed to doing this. But has anyone else had this issue? Heater core gone rogue?
As always Thanks for being such a helpful group!

Thread name catches attention.

What temp does the engine get to? 195-210?. Thermo should be 195. And it should only take 5 min or so to get there from cold start.
If it takes 20 min or better your thermo is failed open or the wrong temp thermo is in there.

Once the engine is warm feel the two hoses to the heater. They should be different temperatures. If the same thr core is blocked or partially blocked.

The third issue can be a broken blend door. The door that either allows recirculating of cabin air or mixes it with outside air.

Any signs of overheating. Pump impeller may be worn or air in the system.

Last try: buy it dinner first.
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Have been having the same problem. My radiator is covered with card board. Heater blows cold air. Was -28F night before last and has been single digits during the day. My solution is warm clothes and gloves.