Heater goes cold unpredictably.
My heater goes cold unpredictably but possibly
more often when idling. The temperature gauge is
normal. What's the problem? Is it fixable by me, a
fairly capable amateur?
Most likely just low on antifreeze. You may need to flush the system, especially the heater core. If you are handy, its not to hard. Plenty of videos on youtube . Try just adding some coolant to the reservoir tank first though. There should be full hot and full cold marks on the tank to help get the correct level. If you are a bit low, watch it for a while afterward to make sure you aren't losing it regularly, could mean more problems.
Of course the first thing to check is the coolant level cold, also check for oil int the coolant and coolant in the oil, if those check OK then you may want to check the cooling systems ability to hold pressure, if the water pump is the least bit weak or leaking it may not be able to deliver a good flow to the heater core, next check the heater hoses, make sure they are not collapsing while running at full operational temps. the only other thing I can think of is a restricted heater core, so when the water flow slows down like at an idle it doesn't have enough flow to sustain good heated air flow. HTH
Thanks! I'll check the level.
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