ok my 97 accord started overheating a while back turns out radiator was kinda clogged fixed that and now still over heats only when running and on low rpms like under 2500 i step on accelerator and it goes back to normal trying to identify problems but nothing really cxomes to mind other than clogged coolant lines or something like that does anyone know whats wrong ...oh and i replaced thermostat a month ago

 

if it cools when you rev it, it might be the water pump. I assume your fans are working.

 

^^^ True that...

 

THe car being inable to cool itself at idle points to one of two main issues. Either your radiator is receiving insufficient airflow, and accelerating cools the car due to increased airflow. This would mean that one or both or your radiator fans are not operating properly.

Assuming the fans are working properly, this description points to an insufficient flow of coolant through the engines water jacket. Leading to overheating. This can be caused by a number of things.

Clogged or blocked coolant passages inside the engine or coolant hoses could be to blame here.

Secondly, if the coolant level drops below a certain point, the water pump cannot move enough water through the radiator at idle to cool the engine. This disappears when the engine is increased in speed, as it can now pass enough water through the engine to properly cool it.

Finally your water pump could be worn out, often times in older cars whose cooling systems have not been properly maintained you can see rust in the engines water hardline, which fouls the impeller and prevents if from mmoving water properly, also the impeller itself can corrode, eventually making it useless.

Do you have any leaks?
Service records of timing belt/water pump service?
When you say your radiator was clogged, were the cooling fins clogged with debris (outside) or was the inside water passages in the radiator clogged with scale/rust?

One more thing to look at if your radiator was clogged from the inside is the ATF cooler. If you have an automatic transmission. If your ATF cooler is leaking tranny fluid into the coolant it will reduce the thermal efficiency of the coolant, meaning that it cannot transfer heat as effectively anymore. It is also possible that the radiator was not completely unclogged or that it is simply time for a new one.