Removal and Replacement
PRECEDING WORK
Model 140 only. Engine removed.
Front covers removed.
Chain tensioner removed.
Guide rail housing removed.
OVERVIEW
LEFT CYLINDER HEAD
Left Cylinder Head Overview (Part 1 Of 2):
Left cylinder head: Ventilation pipe (19):
Remove.
Install.
Left cylinder head: Guide rail pins:
Pull off with impact extractor 116 589 20 33 00.
Install (step 2).
Secondary air injection lines (1 and 2):
Unbolt.
Bolt on.
Model 129: Exhaust system at exhaust manifolds:
Unbolt.
Bolt on.
Model 129: Exhaust system at carrier for exhaust bracket at transmission:
Unbolt.
Bolt on.
Model 129, left cylinder head: Exhaust pipe (22) at front manifold:
Removal.
Install (step 7)
Left Cylinder Head Overview (Part 2 Of 2):
RIGHT CYLINDER HEAD
Right Cylinder Head Overview (Part 1 Of 2):
Model 140, right cylinder head: Air cleaner (5) of secondary air pump:
remove.
install.
Right cylinder head: Dipstick guide tube (6) at oil pan:
unbolt, turn to the side.
install.
Right cylinder head: Dipstick guide tube of automatic transmission (7):
remove.
install (stop 9).
Right cylinder head: Crankcase ventilation (8):
unbolt.
bolt on (step 10).
Right Cylinder Head Overview (Part 2 Of 2):
Model 140: Exhaust manifold at crankcase:
Unbolt.
Bolt on (step 11).
Coolant at crankcase:
Drain (step 12).
Model 129: Coolant hose (9) at rear of cylinder head:
Take off.
Fit on (step 13).
Coolant hose (10) at rear of cylinder head:
Take off.
Fit on (step 14).
Cylinder head bolts (11) on cylinder head to be removed:
Unscrew.
Screw on (step 15).
Bracket (12) 104 589 00 40 00:
Fit on in place of camshaft bearing caps (13) at cylinder head to be removed, take off (step 16).
Engine hoist:
Attach to bracket (12) 104 589 00 40 00 and to rear engine suspension point, detach.
Cylinder heads (14 and 16):
Take off.
Fit on.
Cylinder head contact surface:
Examine.
Cylinder head gaskets (17 and 18):
Replace (step 19).
Cylinder head bolts (11):
Examine, tighten (steps 20 to 23).
Basic setting of camshafts:
Check.
Oil level of automatic transmission:
Check, adjust to correct level.
CYLINDER HEAD BOLT DESCRIPTION
NOTE
Remove cylinder heads together with camshafts and exhaust manifolds once engine has cooled down.
Rotate crankshaft 30° after ignition TDC on cylinder 1 (arrow). In this position, the camshafts can be rotated without the valves coming into contact with the piston crowns.
Mark all four camshaft sprockets and the timing chain to each other with dots of paint (arrows).
REMOVING, INSTALLING
1 Left cylinder head: Remove ventilation pipe (5).
2 Left cylinder head: pull off guide rail pin (1) with impact extractor 116 589 20 33 00 and threaded insert 116 589 01 34 00.
Installation Note
The thread in the guide rail pin (arrow) must be positioned to the front (in direction of travel) when installed.
3 Model 140: Unbolt air cleaner of secondary air injection, remove.
4 Unbolt lines of secondary air injection. Right cylinder head: 1 cylinder head bolt, 1 engine carrier bolt, model 140: 1 oil pan bolt.
Left cylinder head: 1 cylinder head bolt, 1 crankcase bolt below front exhaust manifold, model 140: 1 bolt on left engine carrier.
Installation Note
Replace gaskets.
5 Model 129: Unbolt exhaust system at exhaust manifolds.
6 Model 129: Unbolt exhaust system at carrier of exhaust bracket at transmission.
7 Model 129, left cylinder head: Unbolt exhaust pipe at front manifold in order to gain access to the drain plug in the crankcase.
8 Unbolt dipstick guide tube from oil pan, turn to the side.
Installation note
Replace O-ring according to condition.
9 Right cylinder head: Unbolt dipstick guide tube (7) of automatic transmission at crankcase (arrow) and at automatic transmission.
NOTE:
Seal hole of guide tube at automatic transmission.
10 Right cylinder head: Unbolt crankcase ventilation line (8) from right cylinder head (arrow).
11 Model 140: Unbolt exhaust manifold at rear of crankcase (arrow).
12 Drain coolant at crankcase; to do this, unscrew hexagon socket bolts (arrow) with seal next to left and right engine carriers. Tightening torque 30 Nm.
13 Model 129: Take off coolant hose (9) at rear of cylinder head.
14 Take off coolant hose (10) at rear of cylinder head.
15 Slacken cylinder head bolts on cylinder head to be removed in stages in the reverse order of tightening diagram, beginning at 14, with engine cold.
16 Install bracket 104 589 00 40 00 at the cylinder head to be removed. Unbolt 1st camshaft bearing cap of exhaust camshaft on the right cylinder head and install bracket with dowel sleeves (18a).
Unbolt 2nd camshaft bearing cap of exhaust camshaft on left cylinder head and install bracket with dowel sleeves (18a), tightening torque 21 Nm.
17 Attach engine hoist to bracket and to rear engine suspension point, lift and remove.
Do not damage tensioning rail or guide rail.
18 Examine cylinder head contact surface,
19 Install cylinder head gasket.
Installation note
Pay attention to dowel pins (1) and dowel sleeves (2) for locating the cylinder head on the crankcase.
20 Examine cylinder head bolts. The cylinder head bolts are subjected to a permanent stretch each time they are tightened. If the maximum length (L) of 171 mm (when new 168 mm) is reached before next tightening, the bolts should be scrapped and replaced by new ones.
21 Clean threaded holes.
Free of oil and water.
22 Oil the thread of the cylinder head bolts and the contact surface of the head and insert.
23 Tighten cylinder head bolts in stages in the order of the tightening diagram, starting with 1.
1st tightening stage 55 Nm.
2nd tightening stage 90° tightening angle.
3rd tightening stage 90° tightening angle.
The cylinder head gaskets are not watertight until the engine has reached its normal operating temperature, in other words until a swelling has occurred. For this reason, the cooling system must not be pressure-tested until after the engine has reached its operating temperature.
24 Install in the reverse order.
25 Check basic setting of camshafts.
26 Check oil level of automatic transmission, adjust to correct level.
TIGHTENING TORQUE
SPECIAL TOOLS
