BMW 1989-1995 525i Service Manual page 141

CAMSHAFT TIMING BELT
118-1
118 Camshaft Timing Belt
GENERAL
118-1
CAMSHAFT TIMING BELT REPLACEMENT
(M20 ENGINE)
118-1
To remove camshaft drive belt (M20 engine) . 118-1
To install camshaft drive belt (M20 engine) . .. 118-3
GENERAL
The 1989 and 1990 525i models use an ove rhead cams haft
that is actuated by a toothed rubber drive belt. See Fig. 1. Due
to belt composition and high under-hood temperatures, the
belt is subject to wear. BMW recommends that the belt be re-
placed at least every 50,000 miles, every fou r years, or any-
time belt tension is relieved.
Drive belt
tensioner
Crankshaft
sprocket
Camshaft
sprocket
Drive belt
Intermediate
shaft
sprocket
B332.ENG.B
CAMSHAFT TIMING BELT
REPLACEMENT (M20 ENGINE)
To remove camshaft drive belt
(M20 engine)
1. With the engine cold, drain the coolant and then re-
move the radiator and the radiator cooling fan. See 170
Radiator and Cooling System.
WARNtNG-
AI/ow the cooling system to cool before opening or
draining the system.
NOTE-
The radiator cooling fan nut
(32 mm
wrencii} has left·
hand threads.
2. Remove the metal coolant cross pipe and its hoses
from the front of the engine. The pipe is held in place
with two bolts.
3. Remove the distributor cap. the ignition rotor, and the
black protective cover from behind the rotor. See 120
Ignition System-DME. Place the cap out of the way.
Fig. 1. Camshaft drive belt configuration with tensioner and sprock-
ets.
CAUTlON-
If the belt fails in service. the pistons will contact
and bend the valves. .
4. Loosen the coolant pump pulley mounting bolts.
5. Remove all engine V-belts (alternator, air conditioning
compressor. power steering pump). See 020 Mainte-
nance Program.
6. Remove the coolant pump pulley bolts and the pulley.
7. Remove the alternator bracket from the upper drive belt
cover. See Fig. 2.
8. Remove the rubber guard from the side of the upper
drive belt cover.
CAMSHAFT TIMING BELT REPLACEMENT (M20 ENGINE)