Good morning VaDead.

My 2004 Honda Civic is overheating on an infrequent basis. I had a shop run a diagnostic and they came up with the thermostat. That's been replaced, however we're still overheating.

Currently, overheating occurs when I stop driving. As an example, last night when I stopped at a redlight the heat started blowing ice cold and the temp went up from normal running temp of about 1/2 temp to 3/4+. When I accelerated from the light, the heat started blowing warm again and the temp returned to normal. Toward the end of my ~20 mile trip, the temp went up to nearly max and the air remained cold after the last stop light of my voyage. I am certain the radiator fluid is full (or very near) and the right kind.

Any idea what's going on and/or how to fix it without paying for further diagnostics that don't solve the problem?

Thanks in advance. If I can provide any additional information please let me know.

 

sounds like the cooling system is restricted in some way. I coolant flowing in the radiator? I would guess that the radiator is plugged up or the engine block is plugged in one of the cooling passages due to old coolant breaking down and not protecting the aluminum from corrosion any longer. Current coolant types only last 4 year max, not like the old days.
Regards
Dave

 

Sounds like the fins on the water pump are worn out and not pushing coolant like it's supposed to

 

Thanks for the responses. Radiator was just flushed, so I'm going to assume it's not clogged. I guess we'll replace the water pump.