'92 2nd gen overheating

[nogard]

It was about 70 deg. out and I was on the highway about 3500 RPM and running the A/C. It started to over heat. So I turned off the air. Then it was fine for a while. And then started to heat up again. So I did the trick of turning on the heat to help more cooling of the coolant. This also worked for a while, but then it started to raise back up, it didn't go to the red, but was close. Then I was finally home. Turned it off, it took a long time for it to cool down.

I did check to make sure I had plenty of coolant. I have new hoses, just had a flush and fill this past winter, newer water pump, and the best thermostat I could buy. I did replace the stock fan with an electric one. That was also working just fine.

I think my radiator is clogged. So far I haven't had it overheat again, but I haven't tried to make it do it. It seems like if I work it hard at higher RPM and with the A/C on is when it did it.

My thermostat is a 185 deg. and the fan temp probe is set to turn on at 185. But the surface temp of the radiator is actually 193 deg before the fan turns on. This shouldn't be a problem right? Especially when I'm cruising on the highway.

Any comments? Ideas?

I was thinking about reverse flushing the radiator with water and compressed air. But it is a daily driver, so I need it to be dependable, so the thought crossed my mind to just replace the radiator.

 

[Bumpin' Yota]

Check to see that the thermostat is indeed opening at 185...

Also check to see that the auxiliary fan that is in front of the radiator, etc, is operational. (It should kick on whenver you have the AC on)

Outside of that, I would set up the electric fan to turn on at a lower temp...

How long has it been since your water pump has been replaced?

 

[nogard]

Not sure about the water pump, the person I bought it from had a new one put a one a while back. I looks pretty new it isn't very dirty yet.

I can't set the fan lower, I would have to buy a settable thermometer. Which would be $60.00

How do I tell exactly when the thermostat opens?

I don't think I've ever heard or seen the aux. a/c fan work? I was going to unplug it and jumper it to the battery to test it to make sure the motor is good. I know the fuses are good. And then I was going to check the relays.

I'm pretty sure it is mild pulgged radiator. I messed around with it on the way home today. It wouldn't overheat at high RPM(3500) on the highway. But as soon as I turned the a/c on it did. It would stay hot for a while unless I turned the heat on to help cool it. And when I can to a stop at the bottom of an off ramp the temp dropped right down to were it normally is.

Like I said I have to get around to flushing it. And then I was thinking about addin some Redline Water Wetter. To help increase the efficiencey of the heat transfer.