93 lumina euro 3.4 coolent light?

ok so when i bought the car the coolent light was on i asked the dealer and he said that he did not know why it was on so we poped the hood and checked the coolent it was full what else whould make this light stay on,another problem how come the check engin light comes on when i satart up the car but if i turn the car off for 10 sec i stays off is this just a fluke?:confused:

The coolant light runs off a switch in the passenger side of the radiator. This switch corrodes quickly and turns on the low coolant light. Replace the switch. Runs about $60. You'll find that the probe on the switch is all corroded. Worked for me.........

The coolant light runs off a switch in the passenger side of the radiator. This switch corrodes quickly and turns on the low coolant light. Replace the switch. Runs about $60. You'll find that the probe on the switch is all corroded. Worked for me.........You'll have to use and OBD I diagnostic tool to find out why the check engine light is on. Could be the Engine temp sensor is corroded as well. The alluminum block engines cause the temperature and level sensors to corrode rapidly.