i have have 1990 chevy beretta gt 3.1,low coolant light stays on and runs hot after a

[RED]

drive it for 20 minutes? the coolant is full,no coolant leaks.what the problem?

 

[lonfisk]

if there is no coolant lose from your radiator and it is full then i suspect your thermostat is at fault. it is located at the motor end of your upper radiator hose.

 

[Rod Knocker]

Check for water in the oil. Sounds like a blown head gasket