How to Change the Intake Manifold Gasket on a Ford F-150by Cayden Conor
The intake manifold gasket on the F-150 is heat, chemical and abrasion resistant, and usually lasts quite a long time -- over 100,000 miles. The gasket eventually dries out, allowing air to leak into the engine and oil to leak out of the engine. A bad gasket causes the engine to run poorly -- it might stall while you are driving, and fuel mileage will suffer. If the gasket is cracked bad enough, the truck may not even stay running.
Locate the relay box near the driver's side fenderwell. Using the diagram on the inside of the cover, locate and pull the fuel pump relay. Start the engine and allow it to run until it quits, to relieve the fuel pressure in the fuel system.
Slide the drain pan under the radiator petcock. Open the petcock and allow the coolant to drain. If the coolant is less than five years old and is clean, you can reuse it, otherwise discard it in an appropriate manner.
Slide a socket onto the center bolt on the tensioner pulley. If there is a square hole on the tensioner pulley -- this depends on which engine you are working on -- insert the head of a ratchet into the hole. Push the tensioner toward the center of the engine to loosen tension on the belt. Lift the belt off the pulleys and allow the tensioner to move back into place. Do not let it snap into place.
Disconnect the negative battery cable and lay it aside, ensuring that it does not touch metal. Unplug the wiring harness connector on the alternator. Remove the nut holding the power wire on, using a wrench. Pull the power wire off, then reinstall the nut so that you don't lose it.
Loosen the clamps on the air ducts, using the appropriate socket. Remove the air ducts. Unbolt and remove the air cleaner box, using the appropriate socket. Loosen the clamp on the upper radiator hose at the thermostat, using a screwdriver. Pull the hose off the thermostat housing. Disconnect the heater coolant hose from the bypass tube, using a screwdriver.
Disconnect the quick-connect coupling on the evaporative emissions tube, then remove the tube from the intake manifold, using the appropriate socket. Disconnect the quick-connect coupling on the PCV ventilation tube and remove the tube. Disconnect the fuel supply spring lock coupling on the fuel rail, using your fingers. Unplug the fuel rail pressure and temperature sensor wiring harness connectors. Disconnect the vacuum connector.
Unplug the eight fuel injector wiring harness connectors on the fuel injectors. Unplug the heated PCV element's electrical connector. Remove the brake booster vacuum hose from the intake manifold tube. Remove the 10 intake manifold bolts, using the appropriate socket.
Remove the three coolant bypass tube retaining bolts and the coolant bypass tube. Clean the gasket mounting surfaces with the plastic scraper. Disconnect the charge motion control valve's electrical connector. Disconnect the intake manifold vacuum tube from the valve cover stud and the support bracket, using the appropriate screwdriver. Disconnect the cylinder head temperature sensor's electrical connector and the left and right knock sensor electrical connectors.
Remove the engine wiring harness from the charge motion control valve stud. Lift the intake manifold off the engine. Clean the gasket mounting surface on the intake and the engine, using the plastic scraper and rags.
Smear a thin layer of RTV silicone on the lifter galley mounting surface. Fit the intake manifold gaskets onto the lifter galley mounting surface. Position the intake manifold on the gaskets.
Position the coolant crossover onto the intake, using new gaskets, then install the three bolts and tighten them to 89 inch-pounds of torque. Install the intake manifold bolts and tighten them by hand as far as you can. Tighten the intake bolts to 18 inch-pounds of torque, then retighten them to 89 inch-pounds of torque -- this must be done in two stages.
Reconnect the wiring harness retainer for the CMCV stud and install the nut. Tighten the nut to 89 inch-pounds of torque. Reconnect the CMCV electrical connector, the coolant head temperature sensor electrical connector and the right and left knock sensor connectors.
Reconnect the intake manifold vacuum tube to its support bracket and the valve cover stud. Reconnect the brake booster vacuum hose to the intake manifold vacuum tube. Reconnect the heated PCV element electrical connector, throttle position and electronic throttle control electrical connectors and the fuel injection connectors. Reconnect the fuel rail pressure and temperature sensor electrical connectors. Reconnect the vacuum connector.
Reconnect the fuel supply spring lock coupling on the fuel rail. Insert the PCV tube and connect its quick-connect coupling. Position the EVAP tube and connect its quick-connect coupling on the intake manifold. Reconnect the heater coolant hose on the coolant bypass.
Reinstall the upper radiator hose on the thermostat housing and tighten the clamp. Install the alternator and tighten the bolts firmly. Reinstall the air cleaner and air duct. Reconnect the negative battery cable. Plug in the fuel pump relay. Close the petcock on the radiator and refill the cooling system.
Things You'll Need
- Drain pan
- Set of wrenches
- Set of sockets
- Plastic scraper
- RTV silicone
- Torque wrench
Cayden Conor has been writing since 1996. She has been published on several websites and in the winter 1996 issue of "QECE." Conor specializes in home and garden, dogs, legal, automotive and business subjects, with years of hands-on experience in these areas. She has an Associate of Science (paralegal) from Manchester Community College and studied computer science, criminology and education at University of Tampa.