Hi, I am new to the forums and not sure if this thead has come up before.

I have a 92' civic HB with a swapped D15B7 engine. It's overheating and I can't figure out why. It was overheating going down the highway or stop and go traffic so I replaced the thermostat. Still overheating but i realized the cooling fan isn't comming on. I jumped the wire for the fan switch on the thermostat housing and the fan comes on. I have replaced the switch with two different brand new switches and the fan still doesn't come on when the car gets hot. I have tryed everything, replacing both fan switch and temperature switch on block, rad cap, new thermostat and it still overheats. But if I take the thermostat out and run the car without it, the car stays cool on the highway but still gets hot in the city. I don't think it is the pump because I am getting good pressure in the system. There is no coolant in my oil, no smoke from exhaust, no lack of performance, no coolant loss at all.
Not sure what to do if anyone can help.
Thanks

 

Does leaving the 2P connector for the fan switch jumped so that the fan runs continuously prevent overheating?

Here's where to start. First reinstall the thermostat, top off the coolant in the radiator and reservoir, and then bleed the system exactly as described below. If the system still overheats, then you may want to try replacing the radiator.

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Bleeding the cooling system:

1) Park the car on an inclined driveway with the front end higher than the rear.

2) Push the dash heater lever/**** to MAX heat.

3) Follow the directions in the diagram below (hint: the bleed bolt is located where the upper radiator hose connects to the engine):

 

I suspect the radiator as well. Check that with the bottom hose off, you can pour water in the top and have it flow freely out the bottom. Check that the little brass fins on the outside are not corroded and falling off.

The pressure in the system doesn't come from the pump. (It occurs because water expands and tries to boil when heated). The only real way to tell if the pump is good is to remove it and compare with a new one, make sure the impeller is not worn or corroded.

 

when the car is warm/hot put your hand on the top and then the bottom of the radiator. is the bottom of the radiator colder???

 

Hey guys thanks for all the help. I was reading somewhere that it might be the coolant temperature switch under the Dizzy. I am thinking this might be the problem since my cooland needle will say it is 1/4 warm when I turn the key to run without the engine even on. I ordered the part and it comes in tomorrow so we will see if it works.