My Honda Accord LX is overheating after driving for 20 to 30 mins, but only when I stop with my foot on the brake in drive,(like traffic jams) and I just replaced, get this now, radiator,water pump, thermostat, coolant temp sensor, temp sender, plugs, wires, brakes, crank shaft sensor, speed sensor and all fluids.

It's a 96 model and I'm at my wits end with it. I have done a complete cooling system overhaul and done the pressure test and no leaks. Still have a problem with overheating when in traffic. Gauge reads 3/4 high when stopped but goes back down when moving and the fan works and blows hot air when I cut the heat onto help bring the gauge back down. The head gasket is fine I guess because no water or sludge on oil cap, pressure test, etc. What am I missing here?

 

You need to find out if the fan(s)(if you have two then both should be running at the same time) are coming on as it attempts to overheat. If they are, then likely you have a bad water pump or you need to check compression for a bad head gasket.

 

Fans Are working proper. Water pump is brand new and timing belt. Still no clue whats going on.

 

Did you bleed the air from the system? There is a bleed screw located on top of the engine, would be located in the line at the highest point of the line. This may be the reason it heats at idle as the air blockage may be restricting the coolant flow at idle and at higher RPM's there is enough flow to drop the temp to normal.

 

Bleeder nipple is on the water outlet that the thermostat is mounted in.
If it is not bled after the cooling system has been opened for component replacement the engine will overheat.

 

Thanks. Have been bleeding the air through the radiator cap with heat on. I guess the bleeder nipple is a better way to go. Have not done that, didn't think it mattered one way or the other.

 

Compression test just to be sure.

 

That only works if the radiator cap is the highest point in the system. On our cars the intake manifold is the highest point.

 

Bled the system 3 times and still having this issue. Should I just take the thermostat out and run it for a day to see if it overheats? If it does than I need to lower the thermostat to a 170 rather than the 180 thats in it?

 

No never half a$$ your work or patch things. If it aint working its not right! Lower thermostats can be and are bad news. Your engine is designed to run at a certain temp due to mpg, efficiency, and engine wear. Its not good to compensate for a problem with another problem haha. Like mike said, make sure the fans are working correctly, the thermo being installed correctly is another issue.

 

aftermarket thermostat not oem?

 

sorry just saw the post about the fans. Have you pressure tested the system? and the rad cap? without pressure the system will not cool effectively, most people don't know or aren't aware of that.