Contents: Removal ↡ Installation ↡
It is recommended to remove the engine and gearbox as one unit, i.e. as a single unit, and then separate the engine from the gearbox. The following instructions are generally applicable to all engines, but attention is drawn to the special features of the various engine versions.
Removal
Set the hood to the 90° position. To do this, first unhook the left and then the right stop (1) of the bracket (2) from the first position, and then place the stopper in the second position.
Place rags on the fenders to protect the paintwork.
Remove the ground cable from the battery.
Drain the coolant by removing the drain plugs on the left bottom of the radiator, the left and right side of the cylinder block, or the right side on 280SE models. Crankshaft bearing cap side bolts on V-engines (see arrow A in the figure) not to be confused with coolant drain plugs.
Remove the upper and lower radiator hoses.
Article text obtained from the website (MERCEDESMAN)
Drain the engine oil.
Unscrew the gearbox oil hoses from the gearbox oil cooler, and also unscrew the oil cooler hose clamps and drain the oil.
Pull both clips up from the fan shroud, remove the fan shroud from the bottom bracket and place it on the fan.
Pull both radiator retaining clips upwards and lift the radiator outwards. On 280SE engines, you must first unscrew the oil cooler and lift it upwards out of the guides on the radiator.
On cars with air conditioning (6 cylinders) unscrew the compressor together with the support and put it aside. Coolant pipes (refrigerant) no need to remove. On cars with V-engines, the air conditioning system must be emptied and then the hoses on the twin pipe must be removed.
For vehicles with level control, unscrew the oil pressure pump and set it aside. To do this, unscrew only the bolts shown in the figure with arrows. Remove the hoses and plug them.
Suck the oil out of the power steering reservoir and remove the pressurized oil hoses from the power steering pump.
On 8-cylinder engines, remove the entire exhaust system. On 6-cylinder engines, disconnect the exhaust pipe from the exhaust manifold and from the gearbox.
Disconnect all coolant hoses and vacuum hoses going to the engine. Disconnect the top dead center (TDC) sensor wire at the diagnostic socket by unscrewing the diagnostic socket from its mount (two screws).
Disconnect the throttle control system.
Disconnect the fuel lines.
Disconnect all electrical wires from the gearbox. Remove the inductive sensor for the tachometer from the gearbox. To do this, unscrew the M6 bolt and remove the sensor.
Remove the gearshift lever.
Remove the clutch hydraulic hose from the clutch housing.
Remove the engine shock absorbers on the left and right.
Unscrew the flanges of the cardan shaft and gearbox, move the cardan shaft together with the washers back, first removing the clamping nuts from the connection.
Thread a suitable cable through the engine lugs (arrows), attach the cable to a crane or lift and pull it slightly.
Remove the front engine mounts on the left and right by unscrewing the mounting bolts from below.
Remove the rear engine support or the metal pan with the support by unscrewing the nuts (1) and mounting bolts (arrows).
Carefully lift the engine, tilting it at about a 45' angle and then remove it from the engine compartment. Do this work very slowly and constantly monitor that the engine does not remain hanging on wires, etc. Pay attention not to damage the wall of the engine compartment, as it can damage the windshield washer. It is recommended to use special ears on the engine to lift the engine.
Installation
The engine is installed in the reverse order of removal, subject to the following conditions.
Do not install engine parts until the engine mounts and mount bracket are installed and the engine is hanging by cables.
Mount the rear engine support in a free state.
Roll the vehicle and tighten the clamp nut on the driveshaft joint.
Attach the control lever system and check its operation.
Install and adjust the radiator mount.
Fill with oil, coolant, cooling liquid and check the systems for leaks.
Check the condition of the coolant (density, freezing point).
Set the ignition, adjust the idle speed and gas.
Check the engine for tightness and leaks.
Rubber mounts should be replaced with new ones if they are cracked, worn or deformed.
Remove oil and grease from rubber parts. Tighten all bolts and nuts to the specified torque.
Removing the engine and gearbox is not necessary when you only need to replace the rubber engine mounts.