How to Replace Intake Manifold Gaskets on Vehiclesby Contributing Writer; Updated June 12, 2017
While not common, intake manifold gaskets have been known to fail or leak, requiring that they be replaced. The Vehicles CI engine intake manifold must be removed in order to replace these gaskets. This engine has cooling passages running through it, so this repair requires draining the cooling system first. As well, the ignition system distributor is housed Vehicles the rear of the manifold, so it also needs to removed. If the goal is to replace the factory manifold with an aftermarket performance version, the process is the same.
Under The Hood:
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Remove the intake manifold. Do not remove the intake manifold as a single assembly; remove the upper intake plenum and lower intake manifold separately.
Cover the lifter valley, head openings to the crankcase, the EGR valve, left valve cover, distributor hole, intake ports and any other exposed openings in the engine with protective material.
Clean all of the dirt, grime and other foreign material from the lower intake manifold, upper intake plenum and the top of the engine thoroughly.
Remove the old gaskets using a gasket remover or razor blade. Be sure to remove every bit of gasket and sealant. Any particle, regardless of size, that remains when the new gaskets are installed will hinder their sealing ability. Be careful with the plenum, as this part is made of a polycarbonate plastic.
Lay a thin bead of room-temperature vulcanizing silicone compound at the front and rear edges of the head where the new lower intake gaskets will be installed. Extend it about a half-inch beyond the end of the edges onto the head.
Install the new lower intake gaskets. Two small alignment protrusions on the gaskets fit into two divots on the rear of the engine. Take your time and place the gaskets correctly, but keep in mind the silicone compound will become tacky. For this reason, when laying the gaskets, minimize movement after it is laid on the silicone compound.
Place the lower intake manifold on the top of the engine and reinstall the eight manifold bolts. Do not slide the manifold at all lest you damage the new gasket. The 1999 Blazer manifold bolts require a three-pass torque. Torque all bolts to 22 inch-pounds, then 106 inch-pounds, and finally 26 foot-pounds. This allows for an even torque and seating of the gasket.
Install the new upper manifold gasket on the lower intake manifold.
Reassemble the intake manifold and reinstall removed components and assemblies.
Items you will need
Metric socket set
Ratchet set with extensions
Gasket scraper or razor blade
Foot-pound torque wrench
Inch-pound torque wrench
Intake gaskets, AC Delco part #89017866
Room-temperature vulcanizing silicone compound
Disconnect the negative battery cable in your Chevy 3.4 liter vehicle with a crescent wrench, and move the cable out of the way, being careful not to touch any metal parts.
Remove the radiator cap and locate the drain plug on the bottom of the radiator.
Slide a drain pan underneath the drain valve, then open the valve with an open end wrench and allow the coolant to drain out.
Find the 3 bolts that hold the power steering pump onto the motor, and remove the bolts with a socket wrench.
Detach the power steering pump from the engine block and set it aside while leaving the power steering hose attached to the pump. Remove the serpentine belt from around the pump pulley.
Take the serpentine belt off the alternator and remove the bolts from the alternator with a socket wrench.
Disconnect the electrical connector from the alternator with a socket wrench and remove the alternator from the engine block.
Locate the coolant tube on the passenger side of the engine and remove the hoses that feed into the tube, using a pair of needle nose pliers.
Detach the coolant tube from the top of the engine using a socket wrench to unfasten the bolts holding it in place.
Move the wiring harnesses and vacuum hoses away from the top of the upper manifold plenum while leaving them attached, in order to gain access to the bolts that are holding the plenum in place.
Remove the upper manifold plenum from the top of the engine block, using a socket wrench to detach the bolts.
Locate the lower coolant tube and fuel lines on the driver's side of the engine and detach from the engine block, using a socket wrench to remove the 13mm nuts.
Remove the two intake manifold valve covers using a socket wrench to undo the bolts, and lift the covers away from the engine.
Remove any remaining gasket material from the valve covers and the engine block with a putty knife, so that you have a smooth surface when you're ready to attach the new gasket.
Place a bead of gasket seal around the inside lip of both intake manifold valve covers, and lay the new gaskets out on the lip of the valve covers over the gasket seal.
Place a bead of gasket seal around the lip of the engine block where you will attach the valve covers, and put the covers back on the engine block, using a torque wrench. Tighten the vertical bolts first, then the diagonal bolts in stages until you reach 115 inch-pounds.
Reattach the lower coolant line and fuel lines with a socket wrench, and set the upper manifold plenum back on the engine block and secure it with a socket wrench.
Connect the upper coolant tube to the engine, using a socket wrench, and put the hoses back onto the coolant tube with the needle nose pliers.
Place the serpentine belt around the pulley of the power steering pump and attach the pump to the engine block, fastening the bolts with a socket wrench.
Connect the alternator to the engine block with the bolts, leaving the bolts loose so you can adjust the alternator belt.
Place the serpentine belt around the alternator pulley and pull back on the alternator with a crowbar, tightening the belt. Secure the bolts with a socket wrench while you keep tension on the belt.
Fill the radiator with coolant and put the radiator cap back on top of the tank.
Remove the drain pan from underneath the Chevy and dispose of the drained coolant at an auto supply shop or recycling center.
Items you will need
Open end wrench
Metric socket set
Needle nose pliers
2 new intake manifold gaskets
Park the vehicle on a flat surface and set the parking brake. Open the hood and secure it in place with the hood prop.
Disconnect the spark plug wires from the top of the distributor cap. Remove the distributor cap retaining bolt with a socket wrench. Remove the distributor cap.
Loosen the hose clamps on the upper radiator hose and water pump. Pull the hoses free from the intake manifold.
Remove the bolts holding the manifold in place with a socket wrench. Remove the manifold.
Peel the old manifold gaskets from the engine. If they are stuck, use a flathead screwdriver to pry them free.
Spray the new gaskets with gasket sealer and put them in place.
Set the intake manifold on top of the gaskets and tighten the retaining bolts with a socket wrench.
Attach the radiator and water pump hoses to the intake manifold and tighten the hose clamps with a flathead screwdriver.
Attach the distributor cap to the top of the manifold. Replace the retaining bolt and tighten it with a socket wrench. Replace the spark plug wires.
Items you will need
Slide the drain pan under the radiator petcock. Open the petcock and allow the coolant to drain. Close the petcock. Unplug the intake air temperature sensor. Loosen the clamp on the throttle body air inlet duct, using the screwdriver. Pull the duct off the air inlet. Remove the throttle and cruise control cables, using the screwdriver. Remove their brackets, using the appropriate socket.
Unplug the throttle positions sensor and the idle air control valve electrical connectors. Remove the camshaft position sensor's wiring harness from the intake manifold -- it should just unclip from the bracket. Unplug the camshaft position sensor and lay the harness out of the way.
Label the spark plug wires, so you know which cylinder to attach them to when you put the vehicle back together. Pull the wires off the spark plugs with your fingers. Loosen the clamp on the thermostat bypass hose on the throttle body, using the screwdriver. Pull the hose off the throttle body.
Unplug the ignition coil wiring. Unbolt the ignition coil bracket, using the appropriate socket, then remove the bracket with the coils attached, as an assembly. Lay them aside, leaving the spark plug wires attached. If you can't move it far enough out of the way, label the plug wires and terminals before removing them.
Unbolt and remove the purge solenoid and the vacuum canister solenoid. Loosen the clamps on the vacuum lines on the upper intake manifold, using the screwdriver. Pull the lines off the upper intake manifold.
Unplug and remove the manifold absolute pressure sensor and exhaust gas recirculation valve, using the appropriate sockets. Remove the alternator brace. Unbolt and remove the upper intake manifold.
Clean the gasket mating surfaces using the plastic scraper and shop rags. Position a gasket onto the lower intake manifold. Position the upper intake manifold on the gasket. Install the bolts and tighten them to 18 foot-pounds of torque, working from the center out, in a crisscross pattern.
Reinstall the EGR vale, alternator brace, vacuum lines and the MAP sensor. Reinstall the coil bracket and coils, purge solenoid and vacuum canister solenoid. Reattach the thermostat bypass pipe onto the throttle body. Reinstall the camshaft sensor wiring harness and plug wires. Plug in the throttle position sensor and idle air valve connectors.
Reinstall the throttle and cruise control cables, and tighten the bolts to 115 inch-pounds of torque. Reinstall the throttle body air inlet duct. Plug in the IAT sensor's electrical connector. Refill the radiator with coolant.
Items you will need
Set of sockets
Tape and marker
Disconnect the cable to the negative terminal of the battery using a wrench.
Remove all hardware and wiring that connects to the intake manifold. Make notes of where each part attaches.
Disconnect the throttle position sensor and the EGR valve, located adjacent to the intake manifold. Place these parts and connecting hardware to the side.
Remove the fuel lines from their respective connections to the fuel injectors. Plug the fuel lines to minimize fuel spilling. Disconnect the intake manifold runner control cable from the manifold.
Label the spark plug wires and pull from the boot to remove from their corresponding spark plugs. The spark plug wires must later be connected to the same plugs in order for the cylinders to fire in the correct order.
Remove the bolts that hold the intake manifold to the engine block, and remove the manifold. Pry the intake manifold gasket from the block with a flat-head screwdriver.
Clean the top mating edge of the engine block thoroughly. The surface where the new intake manifold gasket will rest must be smooth and free of debris.
Apply sealant to the gasket surfaces and place it on the mating edge of the engine block. Position the new intake manifold so that it aligns exactly with the cylinder flanges of the engine block.
Bolt the intake manifold to the engine block. Tighten the bolts to 22 foot-pounds with a torque wrench.
Reconnect the spark plug wires with their corresponding spark plugs. Pull the boots over the spark plugs.
Replace all removed parts in their original positions. Reattach all of the fuel lines to the fuel rails and fuel injectors. Reconnect all electrical wiring to its respective part.
Connect the cable to the negative terminal of the battery. Start the engine and let it idle for about ten minutes. Check for leaks around the new intake manifold gasket.
Items you will need
Ratchet and socket set
Intake manifold gasket
Clean shop rag
Removing the Manifold and Gasket
Place the engine coolant drain pan beneath the radiator, open the drain petcock and begin draining.
Remove any wires that prevent the intake manifold from being lifted off. Many accessory and ignition wires are routed near and over the intake manifold. Remove any additional coolant lines from fittings on the manifold. By now, the radiator should be drained enough that the coolant level in the engine has dropped.
Remove the distributor clamp bolt, clamp and distributor.
Remove all intake manifold bolts. Pry and lift the intake manifold up and off of the engine. The carburetor or injection throttle body can remain attached to the manifold, provided you can lift the extra weight. You may need a helper for this task.
Lay shop rags or towels in the center of the engine to prevent debris from falling into the lifter valley. Carefully scrape and clean the old gasket material off of the cylinder heads and the front and rear rails of the lifter valley and the engine block. Do not use an abrasive power sander, as this can damage the gasket surfaces and prevent proper sealing.
Installing the Manifold and Gasket
Set the rubber gaskets along the front and rear rails of the lifter valley. Apply a dollop of silicone at the end of each rail gasket.
Set the new composite head/intake manifold gasket on each cylinder head surface so that each end just rests in the small portion of silicone at the end of the rubber rail gaskets.
Replace the intake manifold assembly carefully. Lower it straight down onto the new gaskets so that they are not moved out of place. A helper may be needed for this part of the procedure.
Install all manifold bolts and tighten -- in sequence from the center out -- to the recommended torque value.
Replace all wiring and hoses. Reinstall the distributor. Refill the cooling system with fluid. Restart the engine and check for leaks.
Items you will need
Socket wrench/assorted sockets
Engine coolant drain pan
Kill the engine on the Saturn and pop the hood. On the side of the engine you can see a metal strip with several large, circular holes. This is the gasket of your intake manifold.
Spray the penetrating oil on the bolts of the manifold gasket to help clear off debris and other gunk from the bolts.
Place your 12mm open wrench on the bolt. There is about an inch or half inch of space between the wrench and the end of the joint the bolt is attached to. The bolt is tightly wound so it takes some manipulating to remove it.
Screw on a 12mm nut behind the wrench until it is flush against the wrench. The wrench is not the only thing separating the bolt and the nut. Slide out the wrench and place your torque wrench over both the nut and the bolt. Twist the torque wrench and the nut inside helps spin the wrench, which helps remove the bolt. Once the bolt is out repeat the same process with the other bolts on the gasket. With all the bolts removed you can slide out the gasket.
Slide the new intake manifold gasket into position but be extremely careful to not put it in at an angle as this is going to crack the gasket, forcing you to find a new replacement. Tighten the bolts back into position and close the hood of your Saturn.
Items you will need
Penetrating Oil spray
12mm Open end wrench