Replacing the cam belt on a biturbo

Replacing the timing belt (any 3 valve biturbo engine)

The timing belt has to be replaced every 40000km /24000 miles.

Note :

When the cam belt fails , severe damage may result to your engine, so my advise, take no risk , as the belt is not expensive and can be replaced in about 5 hours or so.

After buying a new car always check when the belt has been replaced last .In case you can not find out better replace it. Often cars can be found with about 80000 km , this milage is chritical as you can expect that the last revision(including the cam belt change) of the car has not been done unless the reseller can prove this. Be careful with such cars, buy them, but don’t expect to get a ready to run car.

Here a description of how a colleague and I changed the timing belt on my Biturbo 422.

Move car on a lifting stage or something similar, as a few things can only be done from underneath the car

Careful! Never work under the car unless it is in a safely locked position

Battery removal

disconnect and remove battery

Radiator & intake pipe removal

drain radiator

open radiator drain screw (right, bottom) of the radiator

careful! let the car cool down, because fluid may be very hot and under pressure

remove radiator retaining clip
remove all clips from and to the radiator
disconnect thermostat wires (2x)
disconnect radiator fan wires (2 connectors)
release accelerator cable , this might be in the way later
remove the two intake pipes
remove radiator by simply lifting it outside the engine compartment

Compressor and alternator belt removal

from under the car remove the alternator and the conditioner compressor belt

Slaken the nuts of the alternator and the compressor and pivot both in the right direction to

facilitate belt removal

Crankshaft pulley removal

- on biturbo

remove 4 crankshaft pulley capscrews and remove pulley

- on later biturbo ( 222. 422.)

remove 4 crankshaft pulley capscrews as well as central capscrew and remove pulley

For this operation it is necessary to block the flywheel.

Remove the plastic protection that protects the flywheel and block it with a screwdriver.(second person necessary)

Timing belt removal

- remove seven timing cover capscrews (longest screw lowermost) and remove timing cover

removal of this plastic cover is bit tricky, but it is possible.

Best place both camshafts on their marked position.

The holes in the timing pulley are aligned with the marks on the camshaft housing and Piston No. 1 is at TDC

Mark position of both camshafts and crankshaft with a special pen.
Slaken stretcher nut and push back stretcher with a lever, then lock stretcher again b y retightening the stretcher nut, so that no more pressure is on the timingbelt.
Remove timing belt

Reinstalling timing belt

Adjust camshafts and crankshaft to their previously marked position

To adjust the position of the crankshaft you can use the old belt still in position on the toothed pulley on the crankshaft

Replace timing belt
First fit it on the crankshaft toothed pulley, carefully take the belt to the right camshaft and also fit it on that toothed pulley.
After having fitted it through the stretcher also fit it on to the left camshaft toothed pulley.

Two persons might be necessary if the camshaft position is not stable.

Now the marks of the crankshaft and the right camshaft are in its correct position, the left camshaft being still a little bit wrong positioned
Slaken the stretcher nut and the belt stretchens.
With a small hammer give a few careful hits against the stretcher so that it loosens completely and tightens the belt.
Turn the crankshaft carefully clockwise .(engine rotates clockwise) After two rotations the belt should be completely tightened and all the marks should be in the correct position again.

Check this twice. If the marks are not in the previously marked position remove the belt and do the whole operation again.

Careful! The marks must be in position again otherwise serious damage may result to the cylinder head.

tighten the stretcher nut
reinstall plastic cover
reinstall the crankshaft pulley and reinstall the screws. Tighten center screw (if necessary) with 108 Nm and 4 other screws with 29 Nm.

Use screwdriver to lock flywheel during tightening

Reinstall the alternator and compressor belts and retighten all screws

Reinstall the radiator make all the connections .
Reinstall the inlet pipes
Make shure every connection that has been removed has also been reinstalled

Do not overtighten the clips from and to the radiator as during operation the circuit is under pressure.

Check every point in your list and after being shure that nothing has been left over start the engine

It should run as before if everything has been done correctly.