I have a '99 Civic VP that seems content to overheat. The radiator, fan switch, thermostat - all have been replaced. Also not a blown head gasket. Here's what happens: when driving for 30 minutes or so and then idling - the temp goes up rapidly. Once I start moving over 25 mph or so, the temp drops, telling me the fan is not on. Note- the A/C fan turns on though. This has been going on for a couple years, checked by two different shops. My mechanic is baffled, thinking it may be an intermittent wiring issue (said he wishes the Civic had a relay but it does not). He says it will be tricky and maybe impossible to figure this out if it is in fact a wiring snafu.

If anyone has come across this I'd appreciate any input. It's got 240K on it but I'd like to get a few more...

thanks....JD

 

1) Find a new mechanic.

2) Unplug the 2P fan switch connector on the thermostat housing and then short the two terminals of the plug with a jumper wire. When you turn the key to ON(II), does the fan run?

 

And it does have a fan relay, reinforcing Ron's point #1.

 

... unless someone has removed the relay, or messed with the wiring??

on a 97 the relay for the fan is under the hood, by the battery. (passenger side near the windshield) I would imagine the 99's are in the same spot.

 

yes! he called me back and said that there were in fact relays which helps with solving this problem. regarding RonJ's point 2, I'm going to try it. Regarding point 1, I'm going to hesitate on that one because I've had good service with him since '97. But thank-you all for replying, I appreciate it.

 

Has your mechanic suggested a hydrocarbon emissions test to completely rule out the blown head?

 

he didn't mention the hydrocarbon emission test, I'll ask him about it. thanks.