02 4.6L Mountaineer Intake Manifold Replacement

Disclaimer photo was not taken by me

Step-by-step instructions to removing and replacing the intake manifold on an 02 Mercury Mountaineer with a 4.6L SOHC V8. This is a common repair on this engine, in this particular case the manifold was leaking right under the thermostat housing. They designed the intake manifold all one piece with the thermostat housing and cross over. So replacement of the entire assembly is a must.

This Engine is also found in:
2001-05 Ford Crown Victoria, 2006-11 Ford Crown Victoria, 2001-08 Ford Crown Victoria, 2002 Ford Explorer, 1999-04 Ford Mustang, 2007-11 Lincoln Town Car, 2001-08 Lincoln Town Car, 2006-11 Mercury Grand Marquis, 2001-08 Mercury Grand Marquis, 2002 Mercury Mountaineer

product found on amazon

When you are shopping for your intake manifold kit, it should come with a new manifold assembly, thermostat and seal, additional hardware and brackets for mounting. It is very IMPORTANT to pay attention to production date of the vehicle. Vehicles produced after 03/04/02 will be equipped with a coolant heated PCV valve and will need to order the correct manifold to allow for those connections. (although I have heard there is a way to use pre 03/04/02 manifolds on the later gen. It is always easiest and best to make sure to get the right parts on the vehicle)


WARNING: Do not have any open flames or smoke anything while you are around this job. You will have to disconnect the fuel system and it is highly flammable and can ignite quickly!

  • 1. First thing I like to always do on most jobs is disconnect the battery.
  • 2. Drain the coolant. (Multiple ways to accomplish this. I found the easiest way was to just disconnect the lower coolant hose located in the front passenger side bottom corner of the radiator.)
  • 4. Disconnect the the upper radiator hose from the thermostat housing and the small heater hose located to on the passenger side sticking straight up. Along with the little hose next to the thermostat housing. ONLY if your vehicle was the later production with the heated PCV valve.
  • 5. Remove the top half of the air filter housing and the hose connecting to the throttle body.
  • 6. Loosen your serpentine belt and slide it off the alternator. There will be a 1/2 in drive slot on the tensioner you will need to wrench down with a wrench to loosen the belt.
  • 7. Remove the alternator and bracket. first connections on top, then the four bolts holding the top bracket from manifold to alternator. Then you will only have to back out the bottom two bolts a few turns, due to the alternator being slotted it will pull straight up and out.
  • 8. Disconnect all electrical connections going to injectors, coils, throttle body. Including all the vacuum lines and hoses going to the intake manifold, throttle body, and fuel rail. as shown in pictures. You will then want to place them all off to the side.
  • 9. Located and remove the accelerator and speed cables from behind the throttle body, then carefully remove them from there bracket and position them off to the side.
  • 10. Disconnect the EGR hard hose going to the throttle body. Leave the hose in place and be careful not to bend this pipe.
  • 11. Disconnect the fuel line going to the fuel rail. The silver pipe in the picture. The retaining clip will push up and be removed, then a quick connect disconnect tool will need to be inserted and then pulled apart to properly remove this line. Fuel will be present once removed.
  • 12.Clean area. When removing the throttle body and manifold is it important to not allow any debris to fall into the motor.
  • 13. Remove the throttle body. It is held on with 5 bolts to the intake manifold.
  • 14. Remove the thermostat housing and thermostat.
  • 15. Remove the Injectors and rail assembly. Be careful handling this assembly, it needs to be removed without twisting or bending it at all. Try to get it to come straight up, and if you have to use the mounting locations as a pry point to pop the injectors free. Sometimes injectors tend to get stuck into the manifold instead of coming with the rail assembly. If this is the case don’t worry, it can be reassembled and clipped back to place.
  • 16. Remove the remaining intake manifold bolts and intake manifold. Tip the manifold up then slide it outwards. There is a heat insulator that will need to be removed and then transferred onto the new manifold. Is is located directly underneath the manifold and will be brittle.
  • 17. Clean. Once removed there will be allot of build up where the manifold sits. Be careful not to allow debris to fall into engine while cleaning. Brake clean, clean rags, and scotch brite is what I used.
Minimal scaring or pitting is normal around the front coolant passages on higher mileage vehicles.
  • 18. Now insure all gaskets are properly seated inside the intake manifold. And carefully lower the new intake manifold into the valley the same way it came out. Usually the newer manifolds will be smaller then the original. Which makes going in easier then out, and make sure to not scrape anything to avoid gaskets from unseating.
  • 19. When installing the new intake manifold screws, you will need to fallow a specific torque spec and torque order.

* Installing the injectors will require the injector o-rings to be pre lubed. Engine oil works great for this.

  • 20. Install everything in reverse order. Fill with coolant. Test.

Hope this helps! Feel free to comment with tips, tricks or questions! Thanks~

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