it overheats after hiway driving but while in the hiway it's fine. replaced the cap when i found there's coolant leaking thru the old rad cap sides. the fan turns up when i let it idle. could it be the thermostat?

 

If the lower radiator hose is still cool after the engine is hot, then the thermostat should be replaced. In addition, you should bleed the cooling system:

-Park car on an inclined driveway with front end higher than rear.

-Turn dash heater ****/lever to MAX heat.

-Now follow instructions below. The bleeder bolt is located where the upper radiator hose meets the engine.

 

thanks for the quick reply ron.

i have to add that the overflow tank was almost full of coolant when it overheated. when i exited and parked the car i let the car cool down a bit and then refill the rad with coolant and i was able to drive home with no overheat.

i wasn't able to check if the lower hose was cool, should i just replace the thermostat anyway and then bleed? can i just jack the car instead of parking it in an inclined driveway?

thanks again.

 

That's fine. A new thermostat is pretty inexpensive.


Definitely

 

thanks again i will try to replace the thermostat and bleed it tomorrow. please ignore my pm (same message).

if just in case it will have the same problem what else should i look for?

 

one more observation and question ... it seems that the rad is not able to suck back the coolant from the overflow tank, would it be because of a bad thermostat as well?

 

Clogged radiator - easy to replace

Blown head gasket - advanced DIY project

Bad water pump (rare to fail more common to leak)

 

No. This sounds more like a bad radiator cap or excess pressure in the cooling system. Do you see bubbles in the reservoir?

 

i did not notice bubbles in the reservoir. what kind of bubbles should i look for? foamy bubbles?

how would i know a bad radiator cap? i just replaced it although i did not buy it from honda but from canadian tire. what would cause excess pressure in the cooling system? and how to fix it?

additional info/observation when it starts to overheat (that is when the traffic slows down in the hiway) when you rev up the temp goes down and when the traffic speeds back the temp is normal. what would be causing this?

 

Yeah, you might consider purchasing an OEM radiator cap.

Start simple, so just replace the thermostat (OEM) and radiator cap (OEM), and then bleed the cooling system thoroughly. Be sure to follow the bleeding instructions closely. Note that it may take 20-30 minutes for the radiator fan to come on twice.

Post how things turn out when you've finished.