'05 Accord - No heat; changed thermostat

Question

Alright so here's my problem. My 2005 Accord does not have HOT heat coming from the blowers. Sometimes it blows warmish. I just changed my thermostat today, and when I drained my radiator, the reservoir did not empty. The old thermostat looks fine, but I replaced it anyways. I refilled the radiator with antifreeze and let it warm up, and same thing; engine heats up and holds at just under half of the gauge, and blowers blow cold-slightly warm air.

I felt the hoses after it was warmed up and the top is warm, and the bottom is cold. I have a feeling it's the heater core.

Anyone have any other ideas?

Thanks,
Josh

rpmerf · Answer

No heat or not much heat can be the result of 3 things - bad heater core valve, partially clogged heater core, or a bad water pump.

Bad Heater Core Valve
Drain the coolant system.  Remove the hoses from the valve.  Change the temperature slider in the car and watch that the valve opens / closes so the coolant can flow through to the heater core.

Partially Clogged Heater Core
Drain the coolant system.  Remove the heater core hoses.  Do not remove them at the heater core, if you break the heater core, you will have a bad time.  Flush water through both ways.  If it seems to flow good, you are fine.  If it doesn't flow well, there might be a clog.  Pushing water through backwards helps remove dirt and rust that may be stuck in there.

Bad Water Pump
Bad water pump is usually also accompanied by overheating.  The impellers can wear down or break and not rotate with the shaft.  This will lead to flowing less coolant than necessary.

'05 Accord - No heat; changed thermostat

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