BMW E36 (M50 engines, M52) - Head and timing gear

BMW E36 (M50 engines, M52) - Head and timing gear

320i versions, 323i, 323you, 325i, 328i (M50 engines, M52)

The cylinder head is removable, when the engine is cold. The exhaust and intake manifolds remain in place.

A damaged cylinder head gasket can be identified by a variety of symptoms (see article. "Removal and installation of the cylinder head" (316i versions, 318i)).

Removal

Caution. Some steps are described in the article "Removal and installation of the engine"; therefore it is recommended to read this article first.

• Disconnect the workpiece lead (—) from the battery. Caution. This will erase the anti-theft security code for the radio. Before disconnecting the battery, see the instructions in the articles "Removing and installing the radio" and "Removing and installing the battery". Caution. On vehicles with a 6-cylinder engine, the battery is located in the luggage compartment on the right side, next to the spare wheel.

• Raise and support the car.

• Unscrew the front outlet pipe from the collector.

• Drain the coolant (see article "Maintenance"). To do this, unscrew the drain plug in the engine block under the exhaust manifold. Immediately replace and tighten the plug when liquid is poured out.

• Release the clamps and remove the coolant hoses from the thermostat.

• Disconnect the throttle linkage from the throttle lever.

• Remove the oil filler cap.

• Prize off with a screwdriver (arrows in fig. W-10201) round covers and remove the screws hidden under them. Remove the two plastic covers.

• Unscrew the workpiece lead (1, Lynx. W-10156) from the cylinder head.

• Prize off with a screwdriver and remove the cylinder head venting hose (2).

• Unscrew a screw (3) and remove the sensor from the head.

• Remove the two screws (1, Lynx. W-10157) and pull the socket strip upwards. Mark the position of the rubber gasket, which will facilitate subsequent assembly.

• Lift up the metal brackets (2) on each ignition coil and disconnect the plugs. Disconnect the complete socket strip together with the electric cables.

• Unscrew and remove the ignition coils from the cylinder head. Mark the position of the workpiece leads for retrofitting.

• Disconnect the following cables and plugs from the throttle body, by marking them appropriately to avoid alterations during reassembly. When removing the plugs, squeeze the elastic wire locks. The remaining markings in the drawing: 1 – throttle opening sensor plug, 2-plug of air temperature sensor, 3 – coolant lines for throttle preheating, 4 – fuel tank vent hose, 5 – fuel feed line (unpainted connector), 6 – fuel return line (connector painted black). Caution, there is a fire hazard. Do not go near with open fire. Place rags under leaking fuel.

• Disconnect the flexible hose to the idle speed control valve at the bottom, on the inlet pipe.

Caution. The handle's tongue breaks easily. The connector is not visible from the top. Figure W-10159 shows the intake pipe seen from the bottom.

• Unscrew the supports for the intake pipe.

• Unscrew the intake manifold from the cylinder head.

Caution. Do not allow debris to enter the intake pipes, as this would seriously damage the engine.

• Compressing the retaining springs, pull out the connector pins: 1 -temperature sensor, 2 – remote thermometer, 3 – oil pressure sensor, 4 – the idle speed control valve.

• Unscrew the cylinder head cover.

Caution. Remember the position of the rubber washers under the bolts, which will facilitate subsequent assembly.

• Pull out the catches to the side (arrows in fig. W-10180) and disconnect the wiring tunnel from the front of the thermostat housing.

• Remove the cylinder head cover.

• Position the plunger 1. cylinder in TDC position. To do this, turn on 5. gear and push the car forward or rotate the pulley on the crankshaft (in the direction of its rotation) until now, until the cams of the inlet and outlet valves 1. cylinder (on the timing chain side) will be facing each other. In this position, the arrows on the sprockets of both camshafts must point upwards.

• Block the crankshaft at TDC position using a BMW tool 112300 or any other suitable mandrel. To do this, insert the pin through the hole in the engine block into the hole in the flywheel (the arrow in fig. W-1057).

Version VIII 1992

• Remove the transport eyes and the upper chain wheel compartment cover. For assembly, mark the position of the shoulder sleeves of both outer screws. Remove the gasket; use a new one for assembly.

• Unscrew, indicated by arrows (Lynx. W-10130), camshaft housing bolts.

• Press in the upper chain tensioner and lock it in this position using a special BMW tool 113290 (Lynx. W-10133).

• Loosen the chain wheels and remove them together with the chain.

Cars from IX 1992 (with VANOS variable camshaft control)

• Disconnect the oil line from the VANOS adjuster and cover it with a clean cloth.

• Remove the connector plug on the solenoid valve of the VANOS positioner.

• Unscrew the threaded plugs from the positioner housing (arrows in fig. W-10225).

• Remove the bolts from the exhaust camshaft sprocket (arrows in fig. W-10226).

• Press in the upper chain tensioner and lock it in this position using a special BMW tool 113290 (Lynx. W-10133).

• Unscrew the nuts (arrows in fig. W-10227) and remove the VANOS positioner.

• Remove the screws (arrows in fig. W-10228) from the inlet camshaft sprocket. Remove the starting plate from the wheel.

• Remove both chain wheels and chain from the camshafts.

• Remove the bearing bracket of the chain tensioner.

• Unscrew the chain tensioner from the cylinder head.

Caution. Hold the tensioner firmly, because it is under spring pressure.

• Remove the chain guide, then remove the chain from the exhaust camshaft.

Caution. Hang the chain on the wire hook, preventing it from sliding down.

• Remove the two screws (arrows in fig. W-10183).

• Remove the cylinder head bolts in sequence from outside to inside and in several stages. You need a Torx key for this, e.g.. BMW 112250.

Caution. After removing the cylinder head, do not rest it on the sealing surface, as fully open valves can be damaged. It is best to place the head on two wooden strips.