Step by step automotive repair guide on how to replace an intake manifold gasket,
each application will be different, the repair will be similar in scope.
Difficulty Scale: 6 of 10
Begin with the vehicle on level ground, engine cool (off) with the parking brake
set. Use protective gloves, eyewear and clothing.
Step 1 - The intake manifold is sealed to the cylinder
head using a gasket which deteriorate and fail over time. This is a normal occurrence
and can happen more frequently when the
system has not been serviced. Some engine are designed with an upper and lower
Upper Intake Manifold
Step 2 - Start by disconnecting the negative battery
cable from the battery. Then drain the coolant from the radiator and remove all
intake tube ductwork, wiring connectors, fuel lines, injectors, coolant and vacuum
hoses. Next, remove all upper intake mounting bolts and remove the upper plenum.
Then, use tape to seal the intake ports to avoid debris from falling into the engine.
(Note: Older engines will have the distributor mounted on the intake. Make sure
to note-mark the position of the rotor under the distributor cap before removing
it. It must go back in the same exact position for the engine to run properly, an
iPhone pic works great for this. )
Lower Intake Manifold
Step 3 - Once all upper intake accessories and
manifold have been removed, remove all lower intake bolts. Then use a small pry
bar to gently pop the in lower intake from the gaskets and remove the lower intake.
( Note: Before removal use an air pressure to clean excess dirt from the intake
area.) After the lower intake has been removed, use a gasket cleaner (scraper) to
rid the gasket surface of any old gasket/glue etc. Which will create a better sealing
surface for the new gaskets, again taping off the intake ports to avoid engine contamination.
Intake Manifold Removed
Step 4 - After the new gaskets have been put in
place gently install the lower intake manifold onto the gaskets and sealer. ( Note:
Use silicone rubber to help seal at the manifold ends and coolant ports to ensure
a proper seal.) Reinstall mounting bolts in a cross pattern starting in the center
and work outwards in a circular pattern in increments using the proper torque specification,
do not over tighten or the manifold could break. Remove tape from intake manifold
and reassemble using new gaskets. Gently reinstall the positive battery cable and
refill with coolant. Start the engine and allow to run, as the engine comes up to
operating temperature, keep topping off the coolant level and reinstall the radiator
cap. ( Note, check the coolant level in the reservoir as well if equipped.)
Intake Manifold Gasket Replaced
Step 5 - After starting the engine and reinstalling
the radiator cap, check the job for leaks both fuel and coolant. If the engine is
running poorly check the injector wires and coil wire/plug wire connection also
leaks. If further problems exist scan the PCM for
trouble codes and repair accordingly.
An intake manifold is constructed in aluminum or plastic and are prone to leakage
due to high engine temperatures and corrosion. Replacement of the intake manifold
gaskets is common among older and high mileage vehicles. Always be couscous of dirt
falling into the engine and take pictures of the job before and during the repair
to help in reassembly.
- Re-torque the intake manifold mounting bolts after a few miles of driving
to help seal the gaskets.
- Replace the thermostat and gasket.
- Refill with new engine coolant
- Change engine oil and filter shortly after the job completion