Removal and installation the cylinder head (BMW 3 Series E30)

Signs of a faulty cylinder head gasket include:

• Reduced engine power.
• Decrease in coolant level, white smoke from exhaust gases when the engine is warm.
• Coolant in engine oil. Oil level does not decrease, but rather increases. Gray color of engine oil, foam on the oil dipstick. Oil dilution.
• Engine oil in coolant, loss of oil.
• Lack of compression in two adjacent cylinders.

Removal

Disconnect the ground wire from the battery.

Remove the engine compartment hood (see section "Removal and installation the engine compartment hood").

Remove the timing belt (see section "Removal and installation the timing belt").



Open the throttle actuator cover.



Disconnect the gas cable "1" by opening the clamp in the direction of the arrow.



If you have an automatic transmission: disconnect cable "2".

Unscrew bolts "3" and put the cables with the holder aside.

Disconnect the idle speed controller connector "4" and vacuum hoses "5" and "6".



Loosen the clamps and remove the air intake hose.

Turn left and disconnect connector "1" of the air flow meter.



Disconnect connector "2" of valve 4 of the fuel tank.

Disconnect connector "1" of the injectors and the connector of the throttle switch.

Disconnect heating hose "3".

Disconnect fuel hoses "4" and close them with appropriate plugs.

Unscrew the fuel hose holders.

Unscrew the bolts "5" securing the battery support.

Remove the radiator hose.

Raise the car.

Unscrew the front pipe of the exhaust system from the exhaust manifold (see section "Exhaust system").



Drain the coolant from the engine by unscrewing the drain plug on the engine block under the exhaust manifold. After draining the fluid, immediately screw in and tighten the drain plug.



Disconnect the ventilation hose.

Unscrew the cylinder head cover.



Remove the camshaft cover "1"



Loosen the cylinder head bolts by ½ turn in the sequence 10-1. A Torx key size E12 is required to loosen the cylinder head bolts.



You can also place a torque wrench on one of the bolts along the engine block, measure a 93° angle with a protractor, and make a mark on the cylinder head with chalk.

Remove the cylinder head.

Caution: After removal, do not place the cylinder head on the contact surface, as this may damage the open valves. Therefore, place the cylinder head on two wooden spacers.

Installation

Before installation, clean the cylinder head and cylinder block from the remains of the old seal. Do not allow the remains of the seal to get into the cylinder holes.

Cover the cylinder holes with rags.

Measure the flatness of the cylinder head and engine block with a steel ruler in the longitudinal and transverse directions and, if necessary, mill it (work must be performed at a service station).



Check the cylinder head for cracks and the cylinder running surfaces for scratches.

Thoroughly clean the cylinder head bolt holes from oil and other objects.

Caution: There must be no oil in the recesses, otherwise the bolts will not fully tighten the cylinder head, despite being tightened to the required torque. In addition, the engine block may be torn apart.

Be sure to replace the cylinder head gasket.

Apply a new gasket without sealing compound so that it does not cover the holes. The inscription "TOP" should be facing up, and the inscription "FRONT" should be facing the toothed belt.

Replace the O-ring for hole "1" in the engine block.

Before installing the cylinder head, check that the camshaft is in the top dead center position (see section "Removal and installation the timing belt").

Install the cylinder head.

Be sure to replace and lightly lubricate the cylinder head bolts with engine oil. Install only new bolts.

Caution: Tighten the cylinder head bolts very carefully. Before tightening the bolts, check the accuracy of the torque wrench. In addition, a protractor, such as the HAZET 6690, is required to tighten the cylinder head bolts.

You can also place a torque wrench on one of the bolts along the engine block, measure a 93° angle with a protractor, and make a mark on the cylinder head with chalk.



The cylinder head bolts are tightened in 3 passes. In each pass, tightening is performed in sequence 1-10.

1st pass: tighten with a torque wrench to 30 Nm.



2nd pass: tighten with a rigid wrench at an angle of 90°.

3rd pass: tighten with a rigid wrench at an angle of 90°.

Install the toothed belt (see section "Removal and installation the timing belt").

Insert the camshaft cover.

Install the cylinder head cover. Tighten the bolts crosswise to 9 Nm.

Connect the crankcase ventilation hose.

Tighten the front pipe of the exhaust system with new self-locking nuts and a new gasket. Tightening torque: preliminary - 30 Nm; final - 50 nm. Bolts should be pre-coated with high-temperature paste (see section "Exhaust system").

Tighten the manifold support bolts.

Connect all hoses and secure them with clamps.

Connect the electrical wires.

Screw on the fuel pipe holders.

Screw on the cable holders and connect the cables.

Install the throttle lever cover.

Connect the ground wire to the battery.

Fill the cooling system with coolant (see section "Replacing the coolant").

Check the engine oil level. If the cylinder head was removed due to a defective gasket, it is recommended to change the engine oil and replace the oil filter, as coolant may have entered the oil.

Install the engine compartment hood (see section "Removal and installation the engine compartment hood").

Note: There is no need to tighten the cylinder head bolts after 1000 km.