I got a h22 that was running fine until the motor started to overheat. The Temp needle would rise to the red so I would shut it off. Wait for it to cool and drive off. So I changed the Thermostat. with one from Japan lower temp Thermo. Now the needle rises to the 3/4 mark and then the fan turns on and brings the temp down. The question is can the switch for the fan be acting this way? If it is the switch, where is it? How hard is it to change? I have been dealing with this for a few weeks now, all I do now when I drive is watch the temp needle.

Advice?

 

this happens in stop and go driving only or all the time? if you lived somewhere warmed i'd suggest water wetter... you can still mix some of that in but not too much cuz it raises the freezing point...

 

mine used to do that all the time, when i had it in, it turned out to be the water pump, i never would have thought of that, but when i pulled the engine apart, the pump seal was fudged and apparently wasn't flowing water like it should, couseing it to overheat at idle, unless the heat was on. really odd though.... come to think of it, i'm not usre if that was what caused it or not, but regardless, i had to buy a new water pump.

 

If it is the water pump in my situation, how does this effect the fan not coming on until the water temp needle is almost at 3/4 to red? I went under the car and noticed that there was some coolant residue from the water pump seal.

 

i actually don't know, are you sure the fans aren't coming on? all i know is that my car used to overheat at idle, and when i took the engine out, the water pump was bad

 

the water pump supplys water to the motor. thats how it pushes it out the block and head.

 

theres a couple things that you need to check. start the car and look in take off the rad. cap. See if the water is moving. If it is the water pump is fine. If you cant see it feel the lower rad. hose see if it gets warm. If so the coolant is moving. The realy is in the engine fuse box back left on firewall. Its one of the black switches i think that its the second from the top on the right side. Not 100%. Before you replace it check for continuity b/w the pins. Another thing that happens but is really odd is that the rad. itself gets deposits all throughout it and will clog slowly. If u need a used fluidyne i have one its in perfect condition. i can get the slim fan too but u get that **** from Pep Boys.

 

There's two thermo switches for turning on the fan in the older pre 97 H22's. In the 97+ there's one backup thermo switch and the ECU controls the primary fan on and off.

You need to check that your thermo switches are working properly. The proper procedure is outlined in the Helm's manual.