How to Replace a Coolant Expansion Tank

Historically, vehicles used overflow tanks to release pressure on overheated radiators. A thermostat activates at a preset temperature, allowing expanding coolant to overflow into a reservoir. Modern vehicles use sealed radiators with expansion tanks, which allow you to fill the radiator without opening the system and maintain a level of free space to allow for expansion of the coolant with higher temperatures. Replacing an expansion tank, which includes draining the radiator, should take between one and two hours and require the use of five or six tools.

Instructions

1

Remove fluid from the existing expansion tank using a fluid evacuator or turkey baster. Dispose of the fluid properly at an EPA-approved recycling facility. (Contact your local branch of the EPA for approved locations.) Place a bucket on the ground beneath the area where you will be working to catch any additional fluid.

2

Disconnect the upper and lower rubber feed tubes from the expansion tank. Loosen the clamps using a screwdriver, ratchet or pliers, depending on the type of clamps used. Most clamps will be removed using a Phillips-head screwdriver.

3

Locate the retaining bolts. Typically, there are four retaining bolts or screws located at the corners of the tank. Remove these and pull the expansion tank out of the vehicle. You may have to disconnect or remove unrelated parts, such as the air filter housing, or move electrical lines to gain access to the various retaining bolts.

4

Install the new expansion tank in the reverse order of the removal of the old one. Once you have installed the new container and replaced the retaining bolts and the two rubber feed lines, fill the reservoir to the half-full mark with a mixture of 1 part coolant to 1 part water.

5

Place the cap on the reservoir and start your vehicle. Let the vehicle get to operating temperature and check the cap and rubber feed lines for leaks. The only leaks that may appear will be around the two rubber tubes or if the new expansion tank has a crack or has been otherwise damaged. Remove and reattach leaking tubes to ensure they are seated properly. Replace a damaged or cracked tank immediately.