How to Change Radiator Coolant in a 1988 Mustang

The coolant in your 1988 Ford Mustang is critical to the proper function of the cooling system. The coolant is a mix of ethylene glycol and water, mixed to a specified amount to protect the engine from freezing and overheating. The ethylene glycol keeps the mixture from freezing while the water cools the engine. Dispose of the old coolant properly after you have drained it. The mixture is toxic to animals and will contaminate the groundwater if dumped on the ground or in storm drains.

Instructions

1

Open the hood of your Mustang and remove the radiator cap. Be sure the engine is cool before starting this project. A hot cooling system is under pressure and opening the radiator while hot will spray hot coolant.

2

Locate the drain petcock on the bottom of the radiator and slide a drain pan under it. Be sure you use a pan with enough capacity to hold all the coolant in the system. With an adjustable wrench, open the petcock and allow the coolant to drain from the system until it stops. If you do not think all the coolant has drained, you can remove the lower radiator hose at the radiator to check.

3

Close the drain petcock, making sure it is secure, and remove the drain pan from under the radiator. Fill the radiator with new coolant, mixed at a ratio of 50 percent water to 50 percent antifreeze/coolant. It is important that this mixture ratio be used or the coolant will not properly protect the engine, radiator and other cooling system components.

4

Start the engine while leaving the cap off the radiator. Continue to add coolant to the system as the level in the radiator falls. Let the engine run until it reaches normal operating temperature and the thermostat opens. The coolant level will fall rapidly when the thermostat opens; add enough coolant to top off the system when it does.

5

Replace the radiator cap with the engine still running. Let the engine run for a few more minutes, checking the temperature on the gauge in the instrument panel of your car to ensure the engine is not running hot.