BMW 1989-1995 525i Service Manual page 89

CYLINDER H EAD R EMOVAL AND INSTALLATION
113-17
Fig. 40. Engine set to TOC. Sprocket bolts are straight up and down
and loca ting dowel
(arrow)
is in lower left comer. OfT mark on
vibration damper should also be aligned w ith mark on timing
chain cover.
22. Remove the camshaft sprocket mount ing bolts and re-
move the sprocket. Tie the chain up using stiff wire.
CAUTlON -
The crankshaft should not be allowed to rotate
once the camshaft timing chain
is
removed.
23. Check carefully for any remainin g connectors. wiring.
hoses. brackets. wire ties. clamps or compon ents that
will interfere with the removal of the cylinder head.
24. Gradually and evenly loosen and remove the cylinder
head bolts using the sequence shown in Fig. 41. Re·
move the cylinder head .
Fig. 41. Cylinder head bolt loosening sequence.
NOTE -
II the head
is
stuck. use
a
sott-faced mallet or pry gently
with
a
wooden stick.
To install cylinder head (M30 engine)
Prior to installation. clean the cylinder head and the gasket
surface of the cylinder block. Clean the threads of the head
bolts and bolt holes with a thread chaser and remove all for-
eign matter and any liquid from the bolt holes. Avoid letting de-
bris into the cylinders or oil passages in lhe cylinder block.
CAUTtON -
Do not use
a
metal scrape r or wire brush to ctean
the aluminum cylinder head or pistons. II neces-
sary. use
a
hard wooden or plastic scraper.
1.
Check the gasket surface of the cylinder head and the
cylinder block for warpage using a straight edge .
NOTE-
II the cylinder head has been machined.
a
special 0.3
mm thicker gasket should be installed. The thicker gas-
ket
is
available from an authorized BMW dealer.
2. Place a new cylinder head gasket on the surface of the
cylinder block.The cylinder head gasket will fit correctly
in only one orientation. Check that the two locating
dowels are correctly positioned in the block and are not
damaged.
REM OVtNG AND INS TALLING C YLINDER HEAD