Engine M10, M30 (models 316 and 316) pre-August 1988, 318i pre-August 1987, 323i and 325i)
If there is a lot of noise from the running chain, which makes it possible to conclude that the tensioner is not working accurately, remove and check the chain tensioner.
The chain tensioner is fixed on the right side of the engine crankcase. It tensions the timing chain through the force of the tension spring, as well as through oil pressure in the tensioner, which depends on the oil content in the engine.
Unusual noises during the operation of the circuit may have the following causes:
- Poorly vented piston.
- Worn piston.
- Air outlet clogged.
- The ball valve in the piston does not work.
- Too much or too little spring tension.
Withdrawal
Remove locking bolt -E-.
Attention: The bolt is under high tension spring force.
Remove tension spring and piston from tensioner. Examination
Measure the free length of the tension spring. Set value: 155.5 mm.
Shake the piston -K- while checking the free movement of the ball -H-.
Check valve operation. To do this, blow into the piston from side 1 (while the valve must be open). Then blow into the piston from side 2 (now the valve should close).
If not, remove valve -F- from sleeve -G- and clean. The air outlet slot -I- must not be blocked.
Installation
Insert the piston with the spring and a new gasket and lightly tighten the locking bolt just a few turns. Attention: The spring cone must face the locking bolt.
Remove the cylinder head cover and camshaft sprocket.
Move the tensioning bar -1- to both sides until the oil exits through the stopper bolt until you feel resistance.
Tighten the locking bolt to 35 Nm.
Screw the cylinder head cover and camshaft sprocket (see section «Removal and installation of a head of cylinders»).