Notpretty

1997 Honda Accord non-vtec 4 cylinder

Replaced radiator, verified coolant level good, new cap, new termostat, new Rad fan switch, rad fan does work when temp is hot and engine is on.

The engine overheats on hills...even steady minor grades. Probably would overheat in summer time much more than just on hill. But, I think the issue is related to the fact the radiator fan never comes on when the engine is on. I pull into the driveway...turn off the car and the fan immediately kicks on. This has been discussed here before...and people have suggested the Radiator Fan Timing module behind the glove box is the problem. Can anyone confirm this? And is the radiator fan relay for sure fine if the fan is coming on when the engine off? Please help.

Related thread that helped, but I'm still confused: https://honda-tech.com/zerothread?id=1645600

Notpretty

I guess there's no experts here... Hello....Echoooo Echooooo...

sony224422

is your waterpump old?

if so, time to replace it.


as for the fan, if its on when the cars on, its fine, and its supposed to turn on with the car off, so you don't warp your head/block.

:edit: i didn't read that right.

how do you know it doesn't come on with the car? turn on your a/c and see if both come on. i think they both are supposed to.

Notpretty

I know because I have a very steep and long hill near by. I run up the hill and the temp gauge shoots up to the 3/4 mark between Red (Max'd) and 1/2 way. I then park at the top of the hill...quickly, leaving it running...I pop the hood. No fan...nothing. I then turn the key to off and the fan comes on.

I've now replaced:

Main fan switch
Temp Sensor for the computer
Rad Fan timing module behind the glove box
radiator, thermostat, and cap

It is a very specific problem...the fan does not run when the ignition is on. According to the system the fan should come on between after 193 or something like that...the a/c fan should come on at a higher number. It being winter and cold I am able to drive it because to cool it off all I have to do is pull over...turn the key off and wait a bit...cycle the car on and off a couple times and it cools down fairly quickly...but this is no way to drive and I'll screwed in the summer.

The engine has 142,000 on it...has been maintained over its life. But I am now wonder about vaccum advance...it running lean due to fuel mixture issues etc. It only heats up on hills...long steady hills and is especially quick to heat up even on shorter lesser hills after 20 minutes of driving.

HELP...anyone got a clue????

sony224422

did you turn on your a/c and see if both fans come on while your idling?

Notpretty

I just did turn the A/C on and with the key on the fans both came on.

And, I did the jumper wire test on the rear housing switch (Main fan/passenger fan) and both fans came on. I'm now thinking the brand new switch that I installed there is dead. Thoughts?

Notpretty

Additionally...I just discovered this. The lower rad hose is not hot...barely warm. And the upper hose is very hot. So...I doubt the water is hot enough to trigger the switch at the rear housing. But what would cause the water not to circulate...bad thermostat...which was new but a Kragen item. Or a water pump not spinning water due to fins gone... But the latter should cause complete overheating wouldn't you think? Ahhhhhhhh

THoughts?

sony224422

waterpump could be half assing it.. or more likely, bad thermostat from the start.

Ronin1

Agreed, new does not necessarily mean "good". Especially with thermostats. I would put a Honda OEM thermostat in it and be careful to bleed the air out of the system before taking on the water pump.

Is there any seepage of coolant? If it is from the water pump it should show up fairly low down, but the timing belt may show some sign of it.

Also, is the coolant clean looking? Does it smell funny? Either of these could be signs of a head gasket problem.

I would also check the temperature of the heater hoses to make sure that you are getting good flow through the heater core.