How to Change the Head Gasket on an Chevrolet Carsby Contributing Writer
The Chevrolet car is quite possibly Chevrolet car most popular small-block Chevrolet car. Although the Chevrolet car is known for its durability, this does not mean that the Chevrolet car is always problem-free. A blown cylinder head gasket is typically caused by overheating, and results in a substantial loss of power and the harmful mixing of antifreeze and Chevrolet car oil. Replacing the head gasket may initially seem like an arduous task, but on the Chevrolet car the process is much easier than on many other types of Chevrolet car.
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Turn your engine off and leave it for a suitable amount of time until it has completely cooled down. Open up the hood of the vehicle. Use a wrench to remove the bolt clamp from the negative battery terminal. Lift the negative cable away from the battery.
Place a drain pan underneath your radiator. Locate the drain plug at the bottom of the radiator. Remove the drain plug and drain the coolant in to the drain pan.
Remove the mounting bolts attached to the air cleaner unit using a wrench. Remove any connected hoses with your hands and lift it from the vehicle. Locate the intake manifold and remove the bolts which fix that in place. Also lift it from the vehicle.
Remove the mounting bolts from the head gasket. Each bolt must be removed and inserted in the exact hole which it was removed from. The best way to keep track of this is to get a piece of cardboard and begin removing each bolt one at a time. After each bolt is removed place it on the cardboard and put a number above it so you can keep track of which screw you removed and which order it needs to be reinserted in. Lift the head gasket away from the cylinder.
Remove all of the material off the engine block so that it is completely clean. Attach a new head gasket on to the engine block and fix in place with the mounting bolts in the correct order that you originally removed them. Reattach the air cleaner unit and the intake manifold by fixing them in place with the mounting bolts. Remove the radiator cap off the radiator and insert coolant back in to the radiator. Reconnect the negative cable back on to the battery terminal and fix in place with the clamp bolt.
Items you will need
Relieve the fuel system pressure. Remove the fuel filler neck cap and disconnect the electrical connection running to the fuel pump, located on the fuel tank. Run the vehicle until the engine stalls.
Drain the cooling system. Place a oil drain container under the drain fitting on the bottom of the radiator. Turn the drain fitting counterclockwise to drain the fluid from the radiator, using pliers if the drain fitting won't turn by hand. Tighten the drain fitting when the fluid has finished draining from the radiator.
Remove the accelerator cable, cruise control cable and throttle valve cable (on models equipped with automatic transmissions). The cables are located near the throttle body. Carefully push the cable up through the opening in the clips attached to the throttle body.
Label and disconnect the electrical connectors and hoses on the intake manifold. The vacuum and breather hoses running to the manifold will need to be disconnected. The MAP, IAT, and EVAP electrical connectors will need to be disconnected and removed. The electrical connections running to the fuel injectors will need to be removed as well.
Remove the oil fill cap and dipstick assembly. Unbolt the oil fill tube with a ratchet wrench and detach it from the engine block. Rotate it to gain clearance in order to remove it from the engine compartment.
Remove the alternator bracket bolt closest to the engine block with a ratchet wrench.
Remove the EGR pipe from the EGR valve. The EGR valve is located near the brake master cylinder and brake fluid reservoir, near the firewall on the driver side of the engine compartment. Pull the EGR pipe away from the valve to remove it.
Remove the intake manifold support brace mounting bolts with a ratchet wrench and remove the brace.
Remove the intake manifold mounting nuts and bolts with a ratchet wrench, and remove the intake manifold.
Remove the cylinder head bolts with a ratchet wrench. Label the cylinder head bolts upon removal, as they must be installed in the same location. Remove the cylinder head.
Clean the mating surfaces of the cylinder head and engine block. Remove the old gasket and clean off any remaining material with a gasket scraper. Soak a towel with lacquer thinner and thoroughly wipe both mating surfaces until no debris is left on either surface.
Place the new head gasket over the dowel pins and place the cylinder head on the engine block. Finger-tighten the cylinder head mounting bolts. Working from the center bolts outward, tighten the bolts with a torque wrench to 40 ft.-lbs., except for the two bolts on the edge of the cylinder head near the front of the engine, which should be tightened to 30 ft-lbs. After the bolts are tightening to the correct specifications, work again from the center bolts outward, tighten the bolts another 90-degree turn.
Put the intake manifold in place and finger-tighten the intake manifold nuts and bolts. Tighten the nuts and bolts with a torque wrench to 18 ft.-lbs. Tighten the center bolt/nut first, then tighten the bolts/nuts directly to the left and right of that bolt. Tighten the two bolts on the edges of the manifold next, then the two bolts located on the longer side of the manifold.
Install the intake manifold support brace and replace the mounting bolts with a ratchet wrench.
Push the EGR pipe back onto the EGR valve.
Replace the alternator bracket bolt removed in Step 6 with a ratchet wrench.
Install the oil fill cap and dipstick assembly. Rotate the dipstick assembly while lowering it into position. Replace the mounting bolt with a ratchet wrench attaching it to the engine.
Connect the electrical connectors and hoses disconnected in Step 4.
Attach the accelerator cable, cruise control cable and throttle valve cable (on models equipped with automatic transmissions) that were removed in Step 3. The cables are located near the throttle body. Carefully push the cable down through the opening in the clips attached to the throttle body.
Refill the cooling system with the correct amount of engine coolant.
Replace the fuel filler neck cap and connect the fuel pump connection that was disconnected in Step 1.
Start the vehicle and check for leaks around the cylinder head.
Items you will need
Oil drain container
Gain Access to the Cylinder Head
Remove the air intake ducting, throttle body or carburetor, alternator, and the engine drive belt. Drain the engine coolant and oil.
Unbolt the fan shroud and then unbolt the engine fan and clutch assembly. Unbolt the intake manifold from the engine block, then unbolt the air conditioning compressor, but do not remove the compressor lines to avoid having to recharge the system later.
Unbolt the exhaust manifold and move it out of the way.
Remove the Cylinder Head
Draw an outline of the head gasket onto the cardboard box to help you to identify where the head bolts are located. As you unbolt each and remove it from the engine, push the bolt into the cardboard. Unbolt each of the head bolts just 1/4 turn at a time, working clockwise around the cylinder head until you can remove the head bolts with just your fingers.
Pull the cylinder head off of the engine block.
Use the gasket scraper to remove damaged or burnt-on pieces of gasket until both mating surfaces, the engine block and the head itself, are perfectly clean and free of debris.
Position the new head gasket onto the engine block and carefully place the cylinder head on top of the gasket. Install the cylinder head bolts in the order in which they were removed, first tightening them with your fingers, then working counter clockwise with the ratchet, remembering to turn the bolts just 1/4 turn until the head bolts are torqued to the specifications prescribed in your vehicle owner's manual.
Reinstall the removed parts of the engine in the opposite order in which they were initially removed, then fill the truck with coolant and oil before attempting to turn on the ignition.
Items you will need
3/8 inch drive socket set
Remove necessary parts, including the throttle linkage from the throttle body, air-conditioning compressor, alternator, power-steering pump, drive belts, intake manifold, intake manifold gasket as well as the exhaust manifold attached to the cylinder head with the faulty gasket.
Disassemble and remove the cylinder head by removing the valve cover from the top of the cylinder head with a box end wrench, then remove the rocker arms using a socket wrench and pull out the pushrods. Next, easily remove the cylinder head bolts and the head from the engine.
Place the new gasket on the engine block and place the cylinder head on top. Torque cylinder head bolts to 65 pound-feet using a torque wrench while making sure to tighten bolts in a crisscross pattern. Torque should be applied in 20 foot-pound increments to all bolts.
Reassemble engine components in reverse disassembly order, starting with the exhaust manifold. Replace all gaskets and tighten all fasteners using the torque wrench to factory specifications.
Items you will need
Complete set of U.S. and metric wrenches
Disconnect the battery terminals and remove the air cleaner. Disconnect the fuel lines and any connectors from the intake and distributor. Using the tape, tag and number each ignition wire. Disconnect the ignition wires from the spark plugs. Mark the distributor housing to the intake with a paint pen. Remove the distributor cap. Mark the distributor rotor to the cap. Loosen the retainer bolt for the distributor. Lift the distributor up and out of the engine.
Unbolt the valve covers and lift them off the cylinder heads. Remove the bolts from the intake (it might be necessary to pry around the edges of the intake with the screwdriver). Work the intake side-to-side, until it separates from the engine block. Remove the rocker arm nuts and lift the rocker arms off the studs. Slide the push rods out of the guides.
Unbolt the exhaust manifolds from the sides of the cylinder heads. Remove the bolts that are located on the outer perimeter of the cylinder heads. Remove the remaining bolts from the inner surface of the heads. Lift the heads away from the dowel pins. If they do not break free, pry around the heads with the screwdriver. Remove the old head gaskets. Spray the solvent liberally onto the exposed engine block surface. Scrub the mating surface of the engine block with the wire brush. Repeat the cleaning procedure until the old gasket remnants are completely removed.
Align the new head gaskets to the dowel pins and press the gasket down. Place the heads onto the engine block. Prevent the head from falling by loosely installing the head bolts (the head bolts have to be tightened in a specific pattern with the torque wrench--starting from the center working out, tighten the head bolts to manufacturer specifications). Slide the push rods into the guides. Install the rocker arms and nuts. Set the valve lash. Place the new intake gaskets onto the engine block. Apply RTV sealant to the front and back of the block, where the intake will seat. Place the intake manifold onto the block. Install the intake bolts and torque to manufacturer specifications.
Line up the distributor and push it into place. Tighten the distributor retaining bolt. Reinstall the distributor cap and connect the ignition wires onto the spark plugs. Reinstall the exhaust manifolds, with new gaskets, and tighten the bolts. Place the valve cover gaskets on the valve covers. Reinstall the valve covers onto the heads. Install the valve cover bolts and tighten to manufacturer specifications. Reconnect all fuel lines and connectors. Tighten the battery terminals.
Items you will need
Complete socket set
Head gasket kit
Fine-point paint pen
Remove the carburetor and distributor from the top of the intake manifold. The carburetor is attached to the intake manifold with four nuts. One nut is at the base of each corner of the carburetor. Remove the four nuts with a wrench, then lift the carburetor away from the intake manifold. The distributor is held to the intake manifold with a single bolt at the base of the distributor. Remove the nut with a wrench, then pull the distributor straight up to remove it.
Drain the radiator and disconnect the upper radiator hose from the intake manifold. Loosen the single bolt at the bottom of the radiator on the driver's side to drain it. The upper radiator hose attaches to the front of the intake manifold with a hose clamp, which features a single screw. Loosen the screw with a screwdriver, then pull the hose away from the intake manifold.
Remove the intake manifold, the exhaust manifold and the valve cover. The intake manifold attaches to the engine with four bolts on each side of the manifold. Pull out the bolts with a wrench, then lift the manifold off the engine. The exhaust manifold attaches to the side of the cylinder head with six bolts. Remove those bolts with a wrench, then pull the manifold away from the engine until it disconnects from the cylinder head. The valve cover attaches to the top of the cylinder head with four bolts. Remove those bolts and pull the cover off the cylinder head.
Loosen the eight rocker arms, then remove the eight pushrods and the cylinder head. Locate the single nut in the middle of each rocker arm. Loosen the nut on all eight rocker arms until the tip of each rocker arm can be twisted away from the top of its pushrod; then pull the pushrods out of the engine. Using a wrench, remove the 17 bolts that secure the cylinder head to the engine, then lift the head off the engine. Remove the old cylinder head gasket.
Place the new cylinder head gasket onto the head's mating surface on the engine block, then lower the cylinder head onto the gasket. Do not apply gasket sealer to either side of the head gasket. Install each of the cylinder head's bolts, tightening each bolt only in small increments to ensure that the gasket seats evenly. Slide each pushrod through the cylinder head, then position the tip of each rocker arm over its pushrod and tighten the rocker arm's bolt.
Install the valve cover, exhaust manifold and intake manifold. The valve cover must be installed with a new gasket. Coat both sides of the gasket with gasket sealer, then place the gasket along the lip of the cover. Lower the cover onto the cylinder head, then install and tighten each of valve cover's four bolts with a wrench. The exhaust manifold must also be installed with a new gasket, but gasket sealer must not be used. Bolt the exhaust manifold to the cylinder head with the new gasket. The intake manifold uses four gaskets, all of which must be covered with gasket sealer. Place the coated gaskets onto the engine, then lower the intake manifold onto the gaskets and install the manifold's retaining bolts with a wrench.
Connect the upper radiator hose to the intake manifold, and fill the radiator with antifreeze. Slide the distributor into the engine through the intake manifold, then secure the distributor in place with its single retaining bolt. Place the carburetor on top of the engine, then install and tighten each of the carburetor's four retaining nuts.
Items you will need
Valve cover gasket
Exhaust manifold gasket
Intake manifold gaskets