1991 4 cyl opperating temp

[dickboren]

its running at just below 230 in all driving conditions (freeway, city, idle). Is that right?

This is the car that was boiling over until I replaced the coolant tank cap.

Thanks in advance - DB

[boschmann]

That's hotter than I'd want. Does the fan still cycle on & off when idling. I'm assuming the gauge is reading correct as you stated it would boil over when the cap couldn't hold enough pressure. Have you looked between the radiator & A/C condensor to see if there is something restricting air flow? I'd seriously think about a new radiator, it may have poor flow. Try feeling all around it for cold spots or use an infrared temp gun.

[dickboren]

I checked between the radiator & the A/C and it looked clear.

When I was having the boiling over problem I took the upper and lower hoses off and put a hose in the top. All of the water flowed through to the bottom with no back up. Don't know if that is a valid test. I see no signs of any fin damage on the radiator.

I have noticed that the fans do cycle on and off durring a warm idle. I looked in my Bently manual it says the high speed should come on at 195. If that is true and it is at 230, should the fan be on all of the time?

That said, it seems to me if the fan switch was bad, it would at least cool down at freeway speeds.

Could it just be my temp sensor for the gauge? Looks like that is mounted just below the distributor.

Thanks - DB

[boschmann]

I agree, even if the fan switch was bad it wouldn't come into play at highway speeds, there should be enough airflow to keep the car cool without it. Your radiator flow test is not adequate, a radiator shop could check it on a special flow tester. You can get a thermometer & put it in the expansion tank for a fairly close reading to see if the gauge is correct. The best option is to find someone with a temp gun that can check various points in the cooling system. My bet is still on the radiator.