Removal of the intake manifold must be carried out in the following order.
Disconnect the "–" terminal of the battery and remove the heater partition, remove the soundproofing casing of the air flow supply (see fig. 4.26).
Remove the casing covering the engine ignition coils, for which remove the plugs, unscrew the bolts located under them. Disconnect the plug connection (PC) of the ignition coils.
Remove the corrugated boot from the throttle shaft and the air filter housing together with the air flow meter (see fig. 4.115).
Unscrew the "+" wire of the battery from the "plus" terminal of the battery on the front panel in the engine compartment. Insulate and remove the "+" wire of the battery and move it to the side.
Disconnect the plug-in connectors (PC) of the engine wiring harness branch and move the harness to the side along with the cable boxes.
Disconnect the air supply vacuum hose and the vacuum hose from the throttle body.
Attention! When carrying out work on fuel pipelines, ensure that leaking fuel is collected and disposed of.
Prepare a clean rag to collect the leaking fuel and follow the instructions for removing and installing the fuel hoses. Remove the fuel supply line from the distribution line and plug the ends of the hose using the device "13.5.281" and the device "13.5.282". Collect the leaking fuel with a rag and send it for disposal.
Loosen the clamps and remove the hose (1, Fig. 4.109) from the engine crankcase ventilation pipes from the cylinder head cover on the side of cylinders 5–8.
Loosen the clamps and remove the hose (2) from the engine crankcase ventilation pipes from the ventilation system oil separator. Remove the connector (3) of the brake booster vacuum line.
Loosen the bolts (arrows, Fig. 4.110) and remove the crankcase ventilation oil separator from the rear cover.
Attention! There is an oil drain line under the intake manifold, secured to its rear cover. Before unscrewing the intake manifold fastening, it must be disconnected.
Unscrew the nuts (16, see Fig. 4.108) left and right and remove the spacer bushings (15).
Raise the intake manifold by 7-10 cm and carefully move it to the side. Disconnect the oil drain line from the rear cover. Remove the intake manifold by moving it upwards.
Close all openings of the intake manifold and cylinder head. Foreign bodies entering the intake manifold can cause engine failure.
The crankcase ventilation tube is fixed to the intake manifold with a protrusion (1, Fig. 4.111) and is locked by a locking protrusion (2).
Carefully press in the locking lug (2) and pull the crankcase ventilation tube out of the opening in the intake manifold and remove it completely.
If necessary, remove the throttle valve (13, see Fig. 4.115).
Remove the front (12, see Fig. 4.108) and the rear (2) intake manifold covers.
Installation of the intake manifold should be carried out in the reverse order, while it is necessary.
Check the integrity of the sealing gaskets (10, 11, 14, see Fig. 4.108) and make sure they are positioned correctly. Replace the gaskets under the front and rear intake manifold covers. Replace the gaskets and insert the crankcase ventilation tube (7).
Check the position of the lock (1, Fig. 4.111) and the operation of the latch (2) in the intake manifold. Check the oil drain line for damage.
If necessary, replace it and the wear protection gaskets. Ensure that the oil line is laid without kinks.
Remove previously installed plugs from the intake manifold and cylinder heads, replace gaskets (14, see Fig. 4.108).
Check and, if necessary, replace the elastic spacer bushings (2, Fig. 4.112), thanks to which vibration from the cylinder head is not transmitted to the intake manifold.
Replace the sealing gaskets (4). Install the intake manifold. Install the elastic spacer bushings (2) on the outer studs, on the right and left of the intake manifold. Tighten the fastening nuts (1) by hand and center the intake manifold.
Install the remaining elastic spacer bushings and tighten the intake manifold mounting nuts (1) evenly, crosswise, to a torque of 15 N·m (1.5 kgf·m). Assemble the engine.
[Original publication posted on the website: bmwman.ru]