sestrode

thanks, I'll try replacing that cap. Do the aftermarket thermostats quit working completely , or just sometimes?

Will you see bubbles in the radiator and bottle the whole time the engine is running, or is it off and on? And would a faulty thermostat cause excess water in the overflow?

So with the fluid low in the radiator and high in the overflow, does that mean it's a blown head gasket? I haven't noticed any black stuff in overflow but will check.

It started overheating while she was driving and as soon as she bumped the temp setting on the climate control from halfay to about 3/4. Not sure if she changed the fan speed or not though. I recently topped off the radiator but I noticed that when I took the radiator cap off it wasn't full to the top and the overflow bottle was will above the full level. I replaced the thermostat earlier and used an aftermarket model. Are those unreliable? I'm also wondering about a head gasket issue. Although there's no oil in the water or water in the oil. Would a blown head gas cause coolant to be forced from the radiator into the overflow bottle?

Now it's dong something different. Had my mom bring the car over so I could change the temp sensor (it's about a 30 mile drive) and when she got here the fans were both running and the temp gauge was halfway between H and C. So I didn't bother changing the temp sensor. I figured either I didn't get the engine hot enough to turn the fans on when I was first troubleshooting it, or by taking the elec. connector off the sensor (to check the voltage) and then putting it back on it fixed what had been a loose or dirty connection. Then when she left and was about 5 miles from her house ( a 25 mile drive) she went to turn the heater on since it was a little chilly and the temp. gauge immediately jumped up from half- way to full hot. This doesn't make sense at all since I always thought that turning the cars heater on can help to cool an overheating engine, but in this case it caused it to overheat. When she got home and called to tell me about it, the temp gauge had gone back to middle and the fans were running. Any thoughts?

Thanks. Gonna change it today.

Anyone know where I can get a wiring diagram for this cooling fan system? Thanks

I'll check that out, thanks.

I hadn't heard about the green connectors. Where exactly, and what part of the circuit are they for? Thanks

Does it sound like the relays are all working then? I checked the fuses but didn't trace down all the relays and check them yet, I figured checking for voltage at the temp sensor would be enough. I remember reading somewhere the voltage at the sensor plug should be 5 volts which I have on one side, but wasn't sure about the 10 volts I read on the other side of the two-terminal pigtail. Is this cooling system designed to turn the fans on in case of a circuit fault? I couldn't find a decent schematic of this cars rad. fan system. Thanks

Yes, the radiator is full. The heat would sometimes turn cold so I changed the thermostat and now it puts out heat when it should.

Hi everyone, first time poster. I have a 98 Legacy 2.2 and the coolant fans won't come on no matter how hot it gets. I disconnected the pigtail from the temp. sensor to check for voltage at the plug and when i turned the key to the "on" position the fans both came on. When I plugged it back in, both fans shut off. The volt reading was 5 volts on one side of the pigtail plug, and 10 volts on the other contact. Does this mean the temp sensor is bad? Thanks for the help.