I have a 1990 305 automatic. When I drive, say 20 miles or more, and stop at a long signal light the temperature gauge will read over 200 degrees before the radiator fan will come on. The needle goes to where the red starts. Just going down the road again will make it return to normal. Is this normal or could I have a bad sensor? Is there more than one sensor? If it is a sensor where is it and is it hard to replace because of the location?

Thanks, Wayne

 

Thats normal. Every TBI car that I have ever owned or driven does the same thing. Even the trucks.

 

That's exactly what it's supposed to do. The red on the gauge starts at about 240 degrees, and the factory fan switch turns the fan on when the engine reaches about 235 degrees. Evidently GM felt like the engine didn't need any cooling until it reached that temp, strange as that might seem. But they designed, and built, and have successfully warranteed no telling how many millions of cars set up exactly like that; so they must have at least some whiff of a hint of a clue what they're doing.

Sound like your cooling system is working perfectly. Especially if the temp goes right back down within just a few seconds when the car starts moving again.

 

I'm glad to hear that. It just seems strange to me to go that high. Of course it overflows and suctions back when it cools. I just wanted make sure it didn't have a problem. I forgot to mention it's a tpi car but I wouldn't think it would make a difference.

Thanks, Wayne

 

Sounds like your car is working ok. But if it will make you feel better there are some things you can do.

1. Make sure there is not a bunch of leaves and stuff stuck bewteen your radiator and condenser. This can hamper the amount of air your fan pulls in.

2. Make sure your radiator cap is good. The cap creates pressure in the system. This pressure along with your coolant allows the coolant to reach more than 212* without boiling. If the cap is bad or your coolant mixture is not right them it will boil at a lower temp.

3. Lastly you can get a fan switch that will turn your fan on at a lower on temp.

Living in the desert make people out here very aware of over heating problems. We deal with it every summer. A little maintainance in the winter or spring goes a long way in the summer.

Good luck.

Bill

 

My car has been trying to run hotter lately it never ran over 200 and maybe its because its warming up its running warmer but now it wants to go over 220 or stay right at it I installed a 160 t-stat and it takes it longer to get up there now but it still does even going down the highway it will run right over 220? is this ok also the guy installed a flex fan b 4 i got the car my guess is a relay or something went bad and he didnt want to find it so he took off the eletric fan witch I want to put back on soon

Thanks
Chris