My heat was gradually becoming weaker (less hot). I brought it to a shop and my mechanic said it needed coolant/antifreeze. He flushed the coolant system and refilled it. The heat was working great. 500-1000 miles later the heat is losing steam again. It's barely warm enough to defog my windshield. Any thoguhts on how I might fix this myself, if at all possible? Thanks!
More on topic, when the engine is cool, pop the rad cap off and check the level. If its full, put the cap back on and start the engine. When it gets hot, see if the heater hoses on the firewall are hot. If one is significantly hotter than the other (with the heater on "hot" and fan on low) then you may have a plugged heater core. If both hoses are hot, then you may have an issue in the heater box with the blend door or its motor or the controls. I don't know the TJ's that well, but that should give you a place to start.
Hmm, maybe he didn't flush the system well enough? I was having problems with heat with my 4.0L, and I needed to replace my radiator due to a cracked pinch seam along the top. Replaced the radiator after flushing the entire system with a garden hose—which includes sending water down the inlet and outlet hoses to get the heater core in your flush. I had a bunch of weird colored stuff come out. Maybe drain the radiator, disconnect the outlet hose to the heater core and flush again? Or take it back to your mechanic and explain the problem, see if he'll flush again for free (doubt it).
2012 Crush JK Rubicon on 2.5" and 37s
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