The head gasket is located between the engine block and the head cover (or heads, in V-configuration engines). the gasket serves to isolate the cylinders from the cooling ducts around them. In many cases, it also separates the oil and cooling lines to prevent the two fluids from mixing.
The cost of replacing the gasket by a mechanic can be high due to the labor required, so be sure to really be sure you need to change it. Have an expert inspect the car. This article will help you understand how to replace the engine head gasket yourself, saving you money.
Steps
Step 1. Get your car's maintenance manual
You will find detailed explanations and explanatory images. There will also be a list of tools needed to get the job done.
Step 2. Drain the oil and coolant from the engine
Remove the parts located above the motor head. You have to refer to the car's manual, but usually it involves removing the exhaust manifold, air filter, valve cover, and drive belt. On many engines you will also need to remove the timing belt. Make sure you know the alignment of the belt and the markings on it before disassembling it.
- Catalog every part you take apart. You can photograph them or write them on a piece of paper to remind you where they were.
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The gasket is the thin layer you will find once the valve cover is removed.
Install a Head Gasket Step 3 Step 3. Check that the engine block has not been deformed
You can send the engine to a mechanic for a pressure check. If there are no cracks, you can have the motor head (or heads) flattened. Never reassemble the head without first having it flattened.
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Check your maintenance manual to see if the bolts need to be changed each time the gasket is changed.
Install a Head Gasket Step 4 Step 4. Clean the surface of the head and motor block
Do not scratch or remove metal parts, or the gasket may not work properly.
Install a Head Gasket Step 5 Step 5. Clean the bolt seats that secure the head cover to the engine block
Install a Head Gasket Step 6 Step 6. Apply the new gasket to the engine
Use a gasket sealant, if the manual provides for it. Use it in the quantity indicated and only in the places provided. Failure to comply with these instructions can cause damage to the internal parts of the engine.
Install a Head Gasket Step 7 Step 7. Put the head cover back over the new gasket
Install a Head Gasket Step 8 Step 8. Tighten the bolts with a ratchet wrench
Check in the maintenance booklet the sequence of tightening the bolts and the force to be applied to each of them. On some engines it is necessary to do this in 3 steps, plus a final squeeze of a certain number of degrees.
Install a Head Gasket Step 9 Step 9. Reassemble the other parts you removed earlier
Install a Head Gasket Step 10 Step 10. Refit the timing belt to the correct position by carefully turning the crankshaft
Check if your engine has interference between valves and pistons; in this case there is a specific method to rotate the camshaft in order not to damage the valves. If applicable, reinstall the distributor by synchronizing it with cylinder 1. If possible, adjust the valve clearance to the specifications given in the manual.
Install a Head Gasket Step 11 Step 11. Add fresh oil, change the oil filter and fill the cooling system with fresh fluid
Start the engine and run it in neutral with the heat turned on at maximum. In this way, the cooling system will purge any air bubbles. Some engines have a specific procedure to bleed the cooling system - check the manual.
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