[SpaceBallz]

I have a 72 cadillac hearse, it has a new water pump, thermostat, and I just replaced the radiator. But the damn red "water" light keeps coming on shortly after starting it up. Anyone else have this issue?

[ccv66]

I'd buy a cheap Infrared heat guns from harbor freight. Need the temperature of top of the radiators. Does it have a temperature gauge? How quick is the light coming on 30 seconds? 5 minutes? When cold, not ran, leave the heater on full blast with the windows down. Does it take longer for the light come on with the heater going? Is the heater even getting hot? Top of the radiotors cold could be blockage in the block or maybe just a short in the light. If you have a stock fan blade , I'd switch it out to a flex fan, cools better and you free up alot of horsepower

Depending on the ambient temperature, top radiator should be in the ball park 185°ish bottom be 130ish. Light coming on on a 50 year old vehicle may not mean much