GM Firebird 1967-1981 Repair Guide



The cooling system consists of a radiator, belt-driven fan, thermostat, and a mechanical water pump. Air conditioned and high-performance engines are equipped with a viscous drive fan. This fan restricts operation at 1500 rpm in cold weather and 3500 rpm during warmer temperatures. This fan requires less horsepower to drive during high rpm operation and reduces under-hood noise. 1977 and later models are equipped with a special pressure relief radiator cap. Be sure any replacement cap used is the same.

Refer to Repair Guide . Service stations have reverse flushing equipment available; there are also permanently-installed do-it-yourself reverse flushing attachments available. Repair Guide for the coolant level checking procedure. The coolant should periodically be drained and the system flushed with clean water, at the intervals specified in

There is a coolant drain cock at the bottom of most radiators. 6-cylinder engines have a coolant drain plug on the left side of the engine block; V8s engines may have one on each side. Some engines don't have any.

The coolant should always be maintained at a minimum of -20ordm;F freezing protection, regardless of the prevailing temperature. This concentration assures rust protection and the highest possible boiling point. It also prevents the heater core from freezing on air-conditioned models.

Two common causes of corrosion are air suction and exhaust gas leakage. Air may be drawn into the system due to low coolant level in the radiator, a leaky water pump, loose hose connections, a defective radiator pressure cap, or a leaky overflow hose connection to the radiator on the coolant recovery bottle. Exhaust gas may be blown into the cooling system past the cylinder head gasket or through cracks in the cylinder head and block.