Hi Guys, My Low Coolant light keeps coming on in my 1988 Vette. When I check the Radiator its always nearly full. I top it off, The Light goes off and comes back on in about 10-15 minutes.

Today the Coolant temperature is running between 225 - 240. Yesterday the Coolant Temp ran between 196 - 210..... any ideas? Thanks

 

Welcome to the forum. If those temperatures are accurate, the first thing I would do is replace the thermostat.

The intermittent low coolant light might be caused by a faulty sensor. Since I don't know how their sensor operates, it's hard to troubleshoot. If it's not too expensive, you might just try replacing it.

 

And I'll be you checked the level ever time with the car cold and off. Good move but won't find the issue that way as it's always higher in the radiator that way. Get a tester to pressurize the cooling system, AutoZone rents them and HF sells them. Pressurize it to about 15 psi and leave it there and see if it holds pressure (I doubt it will). If you are using Prestone green style antifreeze, it fluoresces under black light.
One area to look is the hose between the block and the TPI. I had one that cracked and a pinhole sized leak, hard to find till I did the above.

 

Thank you, yes I check the coolant level in the Radiator before I start driving when the engine is cold. Thanks for the feedback Pressureizer.

 

Thank you. Can Thermostats be adjusted so that the fan comes on at a lower temperature?