How To Replace a Radiator

Replacing a radiator can take most of a day, but, with care and patience, it is is doable. In order to replace a radiator, you'll need to drain the old radiator, detach any the parts keeping it in place, remove it, install a new radiator, re-install any parts that were removed, and add coolant.

This is a top-level guide and is intended as general repair advice. Each vehicle has slightly different requirements for this kind of job. Reference a repair guide for details specific to your vehicle.

How To Replace a Radiator

1. Safety First

Your radiator has electrical connections. Disconnect the battery before proceeding. You’ll need to raise the vehicle so you can access your radiator. You can use a car jack and stands to keep the vehicle up, but remember to put a chock behind the wheels and engage the parking brake. Wait until the engine is cold before proceeding.

This job can be dangerous, so be extra careful. You will encounter sharp edges and other circumstances that could cause injury. Protect yourself by wearing quality safety gloves and goggles. Be watchful of any moving items while working.

And, to repeat, make sure the car, engine, and coolant are NOT hot!

2. Inspect or Replace

Before jumping in and replacing a whole radiator, take a minute to inspect your entire coolant system. Examine the radiator (or overflow) cap. Check the belts and hoses for damaged, cracked rubber or any leaks. Find the fan clutch between the radiator and the water pump motor (on some vehicles) and make sure there is no play in the bearings.

Don’t forget about your engine thermostat. If your cooling problem has caused the engine to overheat, your thermostat may have been damaged. You may want to replace this small part when replacing the radiator.

3. Drain the Radiator

There are two ways to drain radiators. Remove the radiator cap for either way. Once the cap is removed, you can either open the petcock valve or remove the bottom radiator hose to drain the coolant. Drain the coolant into a plastic reservoir.

4. Disconnect the Radiator

With the coolant drained, you can start removing hoses, clamps and the radiator bolts keeping the radiator in place. You’ll have to disconnect the following parts on most vehicles:

• Radiator reservoir hose
• Upper radiator hose
• Lower radiator hose
• Cooling fan connector
• Cooling fan mounting bolts
• Cooling fan
• Cooling fan shroud
• Transmission cooler lines (many vehicles require special tools to disconnect)
• Engine oil cooler lines (these appear in many high-heat vehicles like 4×4 and Deisel trucks)
• A/C Condenser mounting bolts
• Radiator mounting bolts

Remember to keep all the hoses, connectors, bolts, and components organized. You’ll have to reinstall the parts in reverse order.

5. Remove the Old Radiator

With all the hoses, bolts, and lines removed, you should be able to remove the radiator from the vehicle. Many radiators can be removed by lifting up and out of the vehicle, but some need to be removed from underneath the vehicle.

6. Mount the New Radiator

Set the new radiator in place, and then reattach all the previously removed parts. Start with the radiator mounting bolts and finish with the radiator reservoir hose.

7. Add Coolant

Check that the petcock is closed and that all other valves and caps on the new radiator are shut. With all the hoses and bolts attached, fill the new radiator with coolant. Check oil and transmission fluid levels in case any was lost during the installation.

This is an excellent time to flush your coolant system and replace the old coolant with new coolant. Unless the coolant was recently replaced, we highly recommend performing a flush and fill. The old, drained coolant can become contaminated with debris or transmission fluid during the process of replacing the radiator, and its a safe bet to just flush and install new coolant.

Use distilled water for mixing and adding to the cooling system. The water to coolant ratio must be correct. Most applications use a 50/50 mixture although some may require a stronger coolant ratio. Refer to a Repair Manual for specific applications for your vehicle and typical annual weather.

8. Bleed the air from the Cooling System

Trapped air in the cooling system can cause overheating and reduce the heater’s output performance. The process of bleeding air varies by vehicle, so refer to a repair manual for special procedures to remove trapped air.

As part of the process, you may need to start the car and let it idle. During this step, watch the car closely to make sure it does not overheat. Check the heat gauge and dashboard lights while the car idles for at least 10 to 20 minutes. Also look out for leaks.

Re-check the coolant level in the reservoir (overflow) tank after the job is completed and the system has completely cooled off. Also re-check the automatic transmission fluid and engine oil levels.

Re-check for leaks, especially overnight.

If you have any questions with this process, stop into your local AutoZone store for additional information about replacing a radiator.

If the job is too big for you, seek out one of our Preferred Shops to help you do the job.

Do you need a more in-depth look into your vehicle to help you with your project? ALLDATA, the leading provider of automotive repair information, is now providing DIYers with the same information that the pros use with ALLDATAdiy’s single-vehicle subscriptions.

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Advice, how-to guides, and car care information featured on and AutoZone Advice & How-To’s are presented as helpful resources for general maintenance and automotive repairs from a general perspective only and should be used at your own risk. Information is accurate and true to the best of AutoZone’s knowledge, however, there may be omissions, errors or mistakes.

Be sure to consult your owner’s manual, a repair guide, an AutoZoner at a store near you, or a licensed, professional mechanic for vehicle-specific repair information. Refer to the service manual for specific diagnostic, repair and tool information for your particular vehicle. Always chock your wheels prior to lifting a vehicle. Always disconnect the negative battery cable before servicing an electrical application on the vehicle to protect its electrical circuits in the event that a wire is accidentally pierced or grounded. Use caution when working with automotive batteries. Sulfuric acid is caustic and can burn clothing and skin or cause blindness. Always wear gloves and safety glasses and other personal protection equipment, and work in a well-ventilated area. Should electrolyte get on your body or clothing, neutralize it immediately with a solution of baking soda and water. Do not wear ties or loose clothing when working on your vehicle.

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