How To Replace a Radiator: Fix Radiator Problems

Get Tips for Replacing Car Radiators on Your Own

Liquid-cooled engines, such as the one installed in your car, require a radiator to cool the water that, in turn, removes heat from the engine. It is essential that the engine cooling system function properly regardless of weather or temperature. Given enough time, any failure in the cooling system can and will allow the engine to overheat, and critical components in the engine will warp or melt.  This article will cover the basics so you can replace the radiator yourself.

The engine cooling system on a car is composed of a radiator, hoses, coolant, and fans. The radiator is also responsible for cooling automatic transmission fluid on vehicles equipped with automatic transmissions. So as you see, if you're experiencing radiator problems, they need to be fixed quickly.

Replacing a radiator can be a tedious task, but it is not too difficult for the talented "backyard" mechanic. If it's your first time to change a radiator, expect to spend a full 6 hours on the job. Before you begin, make sure that the car has been parked for several hours. Radiator fluid can build up substantial pressure in the radiator when hot. Do not, under any circumstances, start work if the radiator cap feels warm. Here's how to replace a radiator.

Do not allow antifreeze to sit around. It tastes sweet, and children or dogs may consume it. Antifreeze is very toxic! Use caution! Properly dispose of used antifreeze at a recycling center.

  1. Disconnect the battery. You want to prevent any electric cooling fans from turning on while you are working in that area. Ensure that the ignition is off.
  2. Drain the radiator fluid into a suitable container. The radiator plug is near one of the bottom corners. Simply unscrew it, and the Man and overheated carfluid will flow.
  3. Remove the old radiator:
    1. Take off any plastic covers around the radiator.
    2. Most modern cars are equipped with electric cooling fans. Disconnect the electrical connector to the fan, and unbolt and remove the fan assembly. Take careful note as to how this fan assembly and shroud are put together.
    3. Disconnect the radiator hoses from the radiator. They are usually connected with hose clamps. Use a flat head screwdriver to loosen the hose clamps first. This is a great time to inspect the condition of the radiator hoses. If they look cracked, worn, or have bulges, they need to be replaced. Or even better, since it's a convenient time, go ahead a replace all of the radiator hoses. Better do it now than on the side of the road later.
    4. Disconnect the transmission cooling lines from the bottom of the radiator. Use an open race wrench to loosen the fittings. Be extremely careful that you don't bend or kink the transmission cooling lines.
    5. Finally, remove any clamps, brackets, or screws holding the radiator inside its frame.
    6. Lift the radiator up and out of the car.
  4. Install the new radiator:
    1. Slide the new radiator into place.
    2. Connect any clamps or brackets that hold the radiator in place.
    3. Connect the transmission cooling lines (be careful!).
    4. Connect the engine cooling hoses to the radiator.
    5. Replace the fan and fan shroud.
    6. Reconnect the fan electrical connection.
    7. Replace the plastic covers.
  5. Fill the radiator with fluid. The coolant should be composed of 50:50 ratio of water and antifreeze. Some extremely cold climates may require a higher ratio. Use an antifreeze tester available at any auto parts store to analyze your coolant composition.

    It's a good idea to use distilled water instead of regular tap water. Tap water will do if you're in a pinch, but distilled water lacks minerals that will cause buildups of insoluble salts on the inside of the radiator.

  6. Now check your work to make sure that there are no leaks. Check the radiator fluid composition again with an antifreeze tester. If everything seems okay, take a drive around the block and closely monitor the radiator, fluid, and water temperature. If everything checks out, congratulations to you. You've successfully changed a radiator.

Now you know how to replace car radiators. It's a good idea to watch the fluid level closely for the next few days. If there's a leak in the system, you want to catch it early. 


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