The cylinder head gasket is replaced if it is damaged.
The main signs of damage to the head gasket:
- – insufficient compression (below 1 MPa (10 kgf/cm 2)) in one or more cylinders;
- - breakthrough of gases into the cooling system (seething, foaming of liquid in the radiator, rapid drop in the liquid level in the expansion tank in the absence of external leaks);
- - ingress of coolant into the lubrication system (emulsion on the oil level indicator, stratification of oil drained from the crankcase - especially noticeable in a transparent container);
- - oil entering the cooling system (oil film on the surface of the liquid in the expansion tank).
You will need: a torque wrench, a screwdriver, pliers, keys (regular and socket) "8", "10", "13", "17", head "E-Torx".
Remove the cylinder head cover (see "How to replace the Niva Chevrolet cylinder head cover gasket")
Drain the engine cooling system (see "Changing the coolant").
Depressurize the supply system.
Disconnect the throttle cable from the throttle assembly and the receiver.
Remove the bearing housing together with the camshaft from the cylinder head studs (see "Replacing the hydraulic bearings of the valve drive levers").
Remove the valve drive levers, unscrew all hydraulic bearings of the levers from the holes of the cylinder head (see "Replacing the hydraulic bearings of the valve drive levers") and remove the oil supply rail to the hydraulic bearings.
Disconnect the harness connectors from the throttle position sensor, idle speed control, engine management coolant temperature sensor
Disconnect the injector harness connector.
Disconnect the wiring harness from the knock sensor.
Pull the engine harness out of the way
Disconnect those spark plug wires
Slide off the protective cap and disconnect the wire from the coolant temperature gauge sensor.
Unscrew the four nuts securing the downpipe to the cylinder head
Disconnect the downpipe from the exhaust manifold.
Remove the upper intake pipe brace bolt and loosen the lower brace bolt to move it aside
Loosen the fastening clamp and disconnect the canister purge hose from the throttle assembly
Loosen the mounting clamps and disconnect the cooling system radiator hoses from the cylinder head pipe
Loosen the clamp and disconnect the lower thermostat hose
Loosen the fastening clamp and disconnect the thermostat side pipe hose
Loosen the fastening clamp and disconnect the fluid supply hose to the heater radiator from the pipe of the cylinder head.
Unscrew the nuts of the fuel pipes and disconnect the fuel supply and drain lines.
Remove the top bolt securing the rear intake manifold strut, loosen the bottom bolt of the strut and move it aside
Remove the two nuts securing the starter heat shield
This is how the heat shield fastening nuts are located
Pull the shield aside.
Remove the chain tensioner (see "Replacing the camshaft drive chain tensioner").
Disconnect the power steering pump bracket from the engine (see "Replacing the Camshaft Drive Chain Tensioner Shoe") and move it to the side along with the pump.
Remove the chain from the camshaft sprocket
Place it carefully on the tensioner shoe.
Make sure the chain does not disengage from the oil pump drive shaft sprocket.
It is best to tie the chain with wire.
Remove the ten cylinder head bolts.
The heads of the bolts are made on a turnkey basis "E-Torx", if necessary, you can use the head "13"
Remove the block head.
Removing the block head is more convenient with an assistant, as it is quite heavy.
Remove the gasket located under the head.
To determine the cause of gasket failure, carefully inspect it.
On the edging of the gasket holes, traces of burnout will be visible between the combustion chambers of adjacent cylinders between the combustion chamber and the channel of the cooling system jacket or between the combustion chamber and the channel of the lubrication system.
Thoroughly clean the surface of the block from the remnants of the old gasket.
Remove foreign deposits from the channels of the cooling system jacket (if any).
The photo shows the removal of the old sealant.
The order of tightening the cylinder head bolts.
Install the cylinder head, centering it on the two guide bushings, screw in the bolts of its fastening and tighten them in four stages in a certain sequence (according to the figure):
- - pre-torque 20.0 N m (2.0 kgf m);
- - tighten with a torque of 69.4–85.7 N m (7.1–8.7 kgf m);
- - turn 90°;
- - finally turn it 90°.