GM Prizm/Nova 1985-1993 Repair Guide

Cooling System



See Figure 1

The correct coolant for the Nova and Prizm is any permanent, high quality ethylene glycol antifreeze mixed in a 50/50 concentration with water. This mixture gives the best combination of anti-freeze and anti-boil characteristics within the engine. Do not run the system filled with straight antifreeze or straight water; temperature extremes could damage the engine. For example, undiluted antifreeze will freeze at -8°F while a 50/50 mixture of antifreeze and tapwater freezes at -34°F.

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Fig. Fig. 1: The freezing protection rating can be checked with an antifreeze tester


See Figure 2

Always allow the car to sit and cool for an hour or so (longer is better) before removing the radiator cap. To avoid injury when working on a warm engine, cover the radiator cap with a thick cloth and turn it slowly counterclockwise until the pressure begins to escape.Never remove the radiator cap until the expansion tank cap is removed. After the pressure is completely removed, remove the cap. Never remove the cap until the pressure is gone.

It's best to check the coolant level when the engine is cold. The radiator coolant level should be between the LOW and the FULL lines on the expansion tank when the engine is cold. If low, check for leakage and add coolant up to the FULL line but do not overfill it. There must be room in the jug for normal expansion of hot fluids.

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Fig. Fig. 2: Check the coolant level in the expansion tank


The engine coolant should be changed every 30,000 miles or three years, whichever comes first. Replacing the coolant is necessary to remove the scale, rust and chemical by-products which build up in the system. This is a potentially messy job so have a large drain pan or bucket available along with a healthy supply of rags. Be prepared to deal with fluid spills i