You would have to drain all the coolant before starting to disassemble the engine. If the cylinder liners are detachable (not integral to the engine block) then it is preferable to drain the engine oil too, otherwise some coolant may pass through the O-rings of the cylinder liners and go into the oil sump.
To start disassembly, components that are attached to the cylinder head need to be removed. These include intake manifold, exhaust manifold, distributor cap of the ignition system, spark plug wire, timing belt, rocker cover and other accessories if any.
It is advisable to mark the position of No.1 cylinder spark plug wire on the distributor cap. If the firing order is 1-3-4-2, then the other wires can be attached in that order in the sense of rotation of the engine. Vehicles with distributorless ignition system would not need this step. This work was done on the longitudinally-placed 2.2L Renault J7T petrol engine (manufactured by Française de Mécanique). In this case it was necessary to remove the air ventilation box to make some space.
Only the re-assembly procedure is shown here but it would show whatever needs to be removed. Check the flatness of both the cylinder head and engine block with a precision ruler and a thickness gauge (as specified in the service manual) before starting re-assembly.
Cylinder head, intake and exhaust manifolds removed. This is the time to bring the No.1 piston to the Top Dead Center (TDC). No.1 and No.4 move together so these pistons will come to the TDC.
All engine belts removed (following the service manual).
Exhaust manifold with the old flange gasket (junction between exhaust down pipe and exhaust manifold). Try to keep the exhaust manifold dry if it is made of cast iron. Wetting would increase its chances of developping a crack.
Exhaust manifold with the new flange gasket.
Exhaust manifold bolted to the exhaust down pipe (this can be done later too).
Removing oil from the holes of the head bolts. Use an injection with a plastic tube. If you have to leave the engine block without head, do cover it with a cloth so that no dirt or small objects can go inside the bolt holes. Finally for cleaning the bolt holes, you need compressed air and a bottle of emergency tire inflation can be used if you dont have a compressor.
New head gasket. Align the gasket with the dowel pins.
Prepare the head for installation with bolts held by clips. Once these bolts go into their respective holes, they shall automatically align the gasket. You have the option of using the classical method of first aligning the gasket, placing the cylinder head and then installing head bolts.
Head fitted as per the tightening sequence and specified torques.
Knock sensor fitted.
Gaskets mounted on the intake ports. If you use sealant on these gaskets, they would not be re-usable.
Studs mounted on the exhaust side of the cylinder head.
Exhaust manifold bolted to the head.
Intake manifold bolted to the head.
Now is the time to adjust the valve clearances as per the service manual.
Rocker cover fitted.
Oil vapour recycling hoses (or PCV hoses) installed.
Ventilator box installed (image below).
Accelerator cable installed.
Changing the head gasket is the ideal time for changing the coolant pump (or water pump). If the coolant pump is several years old or is already leaking, then its better to change it (not shown). Timing belt installed after aligning the timing marks on the camshaft and the crankshaft. Tighten the timing belt according to the manufacturer's instructions.
Timing belt cover installed.
Spark plugs and spark plug wires fitted. You can keep spark plugs inside the cylinder head but then it would be hard to rotate the crankshaft due to the compression building up in the cylinders.
Air filter box installed.
If your vehicle has considerable milage, it is worthwhile to check your crankshaft pulley or damper pulley too. Damper pulley has to dampen the vibrations of the crankshaft and for this purpose its construction is different from other pulleys. It has a rubber insert between the inner and outer rings. With milage, rubber deteriorates or starts to separates from the metallic parts. In this case, the outer and inner rings of the pulley don't rotate together and start slipping. If it is the case, fit a new one.
Power-steering belt fitted (below).
Radiator fitted. Coolant filled and air bled (removed). Again, cover the the cast iron exhaust manifold with plastic etc before filling and bleeding the coolant so as to protect it from spillage of coolant.
Front grill and bumper fitted. Test runs passed with flying colours.
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