Replace The Radiator And Fan on a 2005-2010 Mustang GT

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Our first article in our “Diagnosing Overheating Issues” series focused on the biggest culprit, the thermostat. If you followed that article and couldn’t fix your overheating issue, fret not – we’re here to continue the journey until we help you find the problem. This second piece will look at the other primary reasons for an overheating ride: The electric fan and the radiator. These two components work in tandem, feeding fresh, cooled liquid through your engine block to keep things running smoothly.

When one of these two critical cooling components fails, bad things happen fast. You’ll notice your temperature gauge climbing into the red when you’re rolling along at slow speeds or in stop-and-go, and even at highway speeds you may notice things staying a little warm. Let’s quickly break down the symptoms of a bad radiator and failing or broken electric fan:

The Fan: If your electric fan doesn’t kick on when your coolant reaches a certain temperature, it can’t cool your motor down. Even if your radiator is functioning, this will result in hot coolant flushing through your motor. Your electric fan may be bad if it 1.) Doesn’t spin when you attempt to move it with your hand. 2.) Spins freely, like a pinwheel, if you turn it by hand. 3.) Doesn’t turn on when your heat or air conditioner is turned on. If you notice any of these three symptoms, your electric fan is not functioning properly and needs replacement.

The Radiator: A radiator is a pretty simple device: It uses metal fins and lines to absorb heat from your coolant. You can easily tell if your radiator is bad: 1.) It shows visible signs of damage, like crushed fins, stuck debris, or leaking lines. 2.) Your radiator shows excessive corrosion. Corrosion will show as a cruddy, white substance caked onto the radiator. 3.) Your radiator is clogged. You’ll be able to tell it’s clogged if the exit hose on your radiator’s cooler to the touch than other coolant hoses at operating temperature. In nearly all cars these two components are contained in the engine bay as one unit – usually the fan is bolted directly to the radiator. We’ll tackle replacing both units in our test vehicle, a 2006 Mustang GT, in the steps below:

  • 8mm Socket
  • 10mm Socket
  • Large Pliers
  • Flathead Screwdriver
  • 14.2 Quarts of 50/50 Coolant/Water
  • Drip Pan

1. Drain Your Coolant System

Remove your radiator cap, then locate the drain plug on the bottom left corner of the radiator. The drain plug is tucked above the undercarriage splash guard, and can be accessed through a small hole. The OEM plug is yellow and may be fragile, so take care when twisting it. It it’s difficult to twist by hand, use the large pliers to twist it.

Image 7856 from Replace the Radiator and Fan on a 2005-2010 Mustang GT

2. Remove the Factory Air Intake Tube

Locate the pipe clamps on the throttle body and air box. Loosen the clamps with the flathead screwdriver. Disconnect the PCV valve breather tube attached to the driver’s side of the intake tube, just in front of the throttle body. Disconnect the MAF sensor plug from the MAF sensor in the intake tube. Pull the tube off the airbox and throttle body and set aside.

3. Remove the Radiator Cover

Use the flathead screwdriver to lift and pop out the plastic screws securing the radiator cover to the engine bay.

Image 7857 from Replace the Radiator and Fan on a 2005-2010 Mustang GT

4. Unscrew Power Steering Reservoir

Loosen the reservoir’s bolt using your socket and wrench so it can be moved out of the way. We recommend gently wedging it against the airbox and metal lines located on the driver’s side.

Image 7866 from Replace the Radiator and Fan on a 2005-2010 Mustang GT

5. Remove Coolant Reservoir

Squeeze the small coolant line’s steel clamp securing it to the reservoir to loosen and remove the hose. Use the socket and wrench to loosen the coolant reservoir’s two bolts, and remove the unit from the engine bay.

Image 7858 from Replace the Radiator and Fan on a 2005-2010 Mustang GT

6. Unplug the Electric Fan

Use your thumb or the flathead screwdriver to push the electric fan plug’s quick disconnect button outward, unlocking it from the fan assembly. Gently pull on the plug to disconnect it from the fan. Check the connections on both the fan plug and the connector that feeds into the wiring harness. If you see corrosion, bent or broken pieces or other visible damage, this may be the culprit of a non-operational electric fan.

Image 7859 from Replace the Radiator and Fan on a 2005-2010 Mustang GT

7. Remove the Radiator's Coolant Hoses

Use the large pliers to squeeze the steel clamps connecting the hoses to the radiator’s inlet and outlet ports. Shimmy the clamps off the radiator, up each hose. Pull each coolant hose off the radiator. Take care when removing the hoses, so they don’t tear or fray.

8. Remove the Radiator's Top Support Braces

Use the socket and wrench to remove the two bolts located on each top support brace. The ends of the braces securing the radiator are simply two rubber grommets, and can be pulled away to release the braces from the radiator once the bolts are removed.

Image 7860 from Replace the Radiator and Fan on a 2005-2010 Mustang GT

9. Remove the Radiator's Bottom Support Bolts

Use the socket and wrench to remove the four bolts located at the bottom and top of the radiator – there will be two on each side.

Image 7861 from Replace the Radiator and Fan on a 2005-2010 Mustang GT

10. Remove the Radiator and Fan Assembly

Carefully remove the radiator from the engine bay. Take extra care not to damage the air conditioner’s condenser, located in front of the radiator behind the front grille. Puncturing the condenser will cause your air conditioning system to leak refrigerant and fail.

Potential Money Saver: Test Your Radiator

If your existing radiator shows no signs of corrosion or physical damage, you can test whether it's leaking or clogged by jetting some water through it with your garden hose. Leave the inlet and outlet ports open and allow water to flow through the radiator. If water flows freely and minimal debris is found exiting your radiator, then it has not suffered corrosive damage. Cap one end of the radiator and fill it with water from the inlet port. If the radiator holds water, you do not have a leak and you can reuse your radiator, saving money while eliminating the possibility that your radiator is not functioning.

11. Secure the New Fan to the New Radiator

Use the socket to secure the fan assembly to the radiator. There are two bolts on either side, one located on the top left of the radiator, and one located at the bottom right. Once assembled, the unit will be placed back into the engine bay in the same fashion you removed the original units.

Image 7862 from Replace the Radiator and Fan on a 2005-2010 Mustang GT

12. Lower the Radiator and Fan into the Engine Bay

Carefully lower the new assembly into the engine bay, taking extra care not to puncture the condenser. The new radiator and fan assembly will rest in the rubber grommets and supports at the bottom of the engine bay.

13. Reinstall the Radiator's Supporting Bolts

Use to the socket and wrench to secure the four bolts located at the bottom and top of the radiator.

14. Reinstall the Radiator's Top Supports

Use the socket and wrench to secure the top supports onto the frame and posts located at the top of the new radiator.

15. Reconnect the Primary Coolant Lines

Take care to inspect the ends of the coolant lines, checking for cracks, fraying or any possible leak points. Slide each hose onto the inlet and outlet ports of the new radiator, and use the large pliers to clamp the steel connectors back onto the hoses and radiator.

Image 7863 from Replace the Radiator and Fan on a 2005-2010 Mustang GT

16. Reconnect the Electric Fan Plug

Simply slide the connector back onto the plug of the new electric fan. Ensure the quick-release tab that was pulled out during removal is slid back in, locking the connector to the fan plug.

Image 7864 from Replace the Radiator and Fan on a 2005-2010 Mustang GT

17. Reinstall the Coolant Reservoir

Use the socket and wrench to reinstall the coolant reservoir. Once bolted to the frame, reconnect the coolant reservoir's coolant lines in the same fashion they were removed during uninstall.

Image 7865 from Replace the Radiator and Fan on a 2005-2010 Mustang GT

18. Inspect Connections, Then Reinstall Radiator Cover

Use the original plastic plugs and push them through each hole located on the radiator cover. These are self-tapping plugs and they should re-expand when pressed in, locking them to the cover with no tools required. Take care when reinstalling each plug – they are fragile and can break easily.

19. Refill Your Coolant and Burp the System

Use your 50/50 mix of coolant and distilled water to fill your radiator via the coolant reservoir. Once filled, your system will contain plenty of air, which can cause overheating symptoms to persist. Trapped air in the coolant system can affect the cylinder head temperature sensor and create a pocket of air that can block the flow of coolant.

To burp the system, park the car on an incline, with the radiator at the highest point. Remove the radiator cap from the coolant reservoir, and run the vehicle for 10 to 15 minutes. Run the heat at “high”. This will cycle the heater core and move coolant and trapped air through the coolant reservoir, allowing air to escape.

Once the system is burped the coolant level will go down, and it may continue to go down after one or two more re-fills. This is normal and is not indicative of a coolant leak. Once properly filled, test drive your car to determine if your cooling problem has been alleviated.

If your radiator showed signs of physical damage, blockage or corrosion, or if your electric fan did not function properly, you’ve likely solved your overheating issues with these two replacements! If not, fear not – we’ll continue to identify areas of concern that might cause overheating issues in our following articles, so stay tuned!

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I have questions regarding my 2005 mustang overheating issues.

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