How to Change the Head Gasket on Toyota Carsby Contributing Writer
S. Despite its relatively low fuel economy, the Toyota car became a popular vehicle within the United States. If your head gasket becomes damaged, it can cause fluid such as engine oil and coolant to leak into the cylinder, which can cause considerable damage to your engine in the long term. Normally, this type of job should only be carried out by a professional mechanic, but if you feel you're up to the task, you can attempt it yourself.
Under The Hood:
- How to Change the Head Gasket on a Toyota MR2
- How to Replace a Head Gasket on a 22R Engine
- How to Replace a Head Gasket in a Toyota Previa Van
- How to Replace a Head Gasket on a 96 Tacoma
Drain the coolant. Position a clean pan beneath the radiator to catch the coolant draining from the car. Remove the negative battery cable from the terminal. Label and tag the engine components situated toward the top section.
Remove or detach the wires, spark plugs, assemblies, brackets, hoses, cables and bolts. Take out or separate the water filter, cowl top panel in the front, alternator, air cleaner assembly, accelerator cable, the middle exhaust pipe, exhaust manifold support, ignition coil, camshaft position sensor, fuel injectors, intake manifold, timing chain cover, camshaft sprockets and camshaft.
Loosen the cylinder head bolts in a circular sequence starting with the corners and work toward the center point of the cylinder head. Throw the old bolts away. You will install new bolts when you position the new gasket. Raise the cylinder head from out of the cylinder block. Review the cylinder head for damage, dents and leaks.
Install the new gasket face up. Install the new cylinder head bolts with your fingers. Tighten the new bolts with a torque wrench in three steps.
Torque the new bolts for the cylinder head to 22 foot-lbs. Turn the bolts an extra 90 degrees for the second pass. Pivot the bolts another 90 degrees in the third pass. The tighten bolt numbers for the Toyota MR2 with a 1NZ-FE engine on the top row are 8, 4, 2, 5 and 9 from left to right. The bottom bolt numbers from left to right are 10, 6, 1, 3 and 7.
Return the engine part back under the hood of the Toyota MR2: wires, hoses, covers, caps, anchors and brackets. Look at the tag you label to help identify the components. Put coolant back in the coolant system reservoir and place new engine oil in its tank. Connect the negative battery cable to the battery terminal. Crank the engine and check for leaks.
Items you will need
Ratchet and socket
New head gasket
Remove the cable from the negative battery terminal with a socket wrench. Disconnect the flange nuts from the exhaust pipe, and detach it from the exhaust manifold. Place a large container under the radiator drains, and drain the coolant from the cooling system into the container for reuse.
Disconnect the air cleaner from the carburetor with a socket wrench, including its hoses. Place a shop cloth over the carburetor to keep debris out of the engine. Disconnect any vacuum hoses and fuel lines as required to gain access to the cylinder head.
Record the positions for the electrical leads on the spark plugs, and detach them them from the spark plugs. Mark the distributor housing and engine block to ensure you can install the distributor in the correct position later. Disconnect the distributor assembly with a socket wrench. Remove the mounting nuts from the valve cover, and detach the valve cover. Detach the camshaft seals.
Turn the crankshaft clockwise to align its timing mark with the timing mark on the timing chain. Remove the mounting bolt for the camshaft sprocket with a socket wrench, and detach the distributor drive gear from the camshaft. Hold the camshaft sprocket in place with wire, and disconnect the cover for the timing chain from the cylinder head.
Remove the mounting bolts from the cylinder head with a socket wrench. Insert pry bars under the front and rear of the rocker arm assembly, and pry it off the mounting dowels. Lift the cylinder head from the engine block, and drain the oil from the crankcase to avoid contaminating the oil with coolant.
Remove the old gasket from the engine block, and apply liquid sealer to the gasket mounting surface on the block. Place a new cylinder head gasket on the engine block, and mount the cylinder head to the dowels.
Turn the camshaft clockwise until its timing pin points straight up. Remove the wire holding the camshaft sprocket in place, and turn the crankshaft until the hole in the camshaft sprocket points straight up. Hold the camshaft sprocket in place with the length of wire. Mount the rocker arm assembly over the dowels on the engine block.
Tighten the mounting bolts to the cylinder head in three separate passes with a torque wrench. The final torque on the mounting bolts must be between 52 and 63 foot-pounds. Replace the timing chain cover, and tighten its mounting bolt to between 7 and 11 foot-pounds.
Remove the wire holding the camshaft sprocket in place, and mount the sprocket to the dowel on the camshaft. Mount the drive gear for the distributor to the crankshaft, and tighten the mounting bolt for the crankshaft to between 51 and 65 foot-pounds with a torque wrench.
Turn the crankshaft clockwise to align its timing marks, and adjust the valve clearance. Turn the crankshaft 352 degrees clockwise to align the Before Top Dead Center mark on the crankshaft pulley with the timing mark on the crankshaft.
Install the distributor and spark plugs, using the marks you made in Step Three as a guide. Install the seals for the camshaft, and replace the engine oil. Lubricate the distributor drive gear and valve rockers with clean engine oil. Replace the valve cover, and tighten its mounting bolts to between 8 and 11 foot-pounds with a torque wrench.
Connect all electrical wiring and vacuum hoses you removed to access the cylinder heads. Replace the coolant in the cooling system, and connect the air cleaner to the carburetor with a socket wrench. Connect the exhaust pipes to the exhaust manifold, and tighten the flange bolts to between 25 and 33 foot-pounds with a torque wrench.
Connect the cable to the negative battery terminal with a socket wrench, and start the engine. Wait for the engine to reach its operating temperature, and adjust the timing, idle speed and fuel mixture.
Items you will need
Ratchet wrench and socket set
Container for coolant
Turn the engine off and let it cool down for at least an hour. Lift up the hood of your Toyota Previa van. Locate the battery. Use an adjustable wrench to remove the clamp bolt, which is fixed to the negative battery terminal. Pull the negative cable away from the terminal.
Locate the drain plug on the radiator. The plug will be at the very bottom. Place a drain pan directly underneath the drain plug. Remove the plug and drain the coolant into the pan. Once the radiator is empty, reattach the drain plug.
Use your wrench to remove the mounting bolts from the air filter unit, alternator and exhaust manifold. Lift them all from the vehicle and place them in a safe area, as you will need to reattach them later. Ensure you do not damage the parts in any way.
Use your hands to remove the coolant line and lower and upper radiator hoses from their connectors. Simply pull them out with your hands. Remove the mounting bolts attached to the timing belt cover and lift it from the engine. This will give you access to the head gasket.
Remove the bolts attached to the cylinder head, starting at the far left-hand side and working your way around in a cross-hatch pattern. Lift the cylinder head off the engine block and move to one side. Remove the damaged head gasket.
Install the new head gasket onto the engine block. Place the cylinder head back on top of the gasket. Reattach the cylinder head bolts to a torque of 23 foot-pounds using a toque wrench. Place the timing belt cover back in place with the mounting bolts. Insert the coolant line, as well as the upper and lower radiator hoses, back into their respective connectors.
Place the exhaust manifold, air cleaner unit and alternator back onto the engine and secure in place with the mounting bolts. Screw the radiator cap off the radiator and pour coolant back into the radiator. Attach the negative cable back onto the battery and secure in place with the clamp bolt.
Items you will need
Give your Toyota Tacoma a few hours to cool down. Disconnect the battery terminal ground cables. Place a clean jug under the radiator to catch the coolant when it drains. If the coolant is clean, reuse the fluid.
Label and attach a tag to each component for identification. Disconnect the exhaust pipe off of manifold. Lift the air cleaner assembly from the automobile, including the hoses. Drape the carburetor with a clean cover. Empty the motor oil. Disconnect the heater hoses, accelerator cable and wires: cold mixture heater wire, temperature indicator, fuel cut solenoid valve and water temperature gauge sender.
Disconnect the various lines and hoses: charcoal canister, brake booster, main fuel line, fuel return line, vacuum switching valve including the bracket. Remove the engine harness, distributor, spark plugs, valve cover and bracket for the power steering unit.
Use the crank pulley bolt to pivot the engine to the right until the piston sits at Top Dead Center. Take off the semi-circular plug, cam sprocket bolt and glide the distributor gear and the spacer from the cam. Keep the chain connected to the sprocket. Sit the sprocket on the vibration damper. Tie a piece of wire to the chain to hold it up away from the engine. Remove the bolt of the timing chain cover.
Undo the cylinder head bolt in sequence recommend by Toyota. Consult a Tacoma repair manual for the appropriate pattern. Allow for two or three passes for the bolts to come off. Lift the cylinder head and worn gasket. Sit the cylinder head on a worktable. Use a screwdriver if you have trouble lifting the gasket out of place. Clean and scrape the area well, mating surface.
Place liquid sealer on the block's front corners and position the new head gasket. Align the gasket with dowel for correct positioning. Place the rocker arm assembly on top of the dowels. Position the mounting bolts of the cylinder head. Torque the bolts in three passes. The bolts appropriate tightness is 58 foot-pounds. Consult a Tacoma manual for the correct sequence and torque specification.
Replace the chain cover belt to 9 foot-pounds. Engine should be set to Top Dead Center. Place the sprocket on the camshaft dowel. Replace the distributor and cam thrust plate. Replace all other engine parts back on the Tacoma, including assemblies, lines, hoses, wires and cables. Check with a repair manual for the torques specifications for the rest of the bolts. Assure all hoses are snug in place and are not loose.
Reconnect the battery cables. Replace the motor oil and coolant. Turn on the engine to warm-up. Adjust timing and check fluid levels. Test the vehicle to assure proper operation. Look for any leaks.
Clean the cylinder head and mating surface of the gasket. Inspect the area for leaks, dents, crack or defects. Position the No.1 piston in Top Dead Center or TDC by turning the crankshaft. Install a new gasket and position the cylinder head. Use new mounting bolt on the cylinder head.
Items you will need
Ratchet and socket
New head gasket