lock MITSUBISHI MONTERO 1991 Service Manual

\003
3.0 L V 6 - V IN S [ B ,C ,S ]

1 991 M it s u bis h i M onte ro
1991 ENGINES
Mitsubishi 3.0L V6
Montero, Pickup, 3000GT
* PLEASE READ THIS FIRST *
NOTE: For engine repair procedures not covered in this article,
see ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION article
in the GENERAL INFORMATION section.
ENGINE IDENTIFICATION
Engine may be identified by using Vehicle Identification
Number (VIN) stamped on a metal pad, located near lower left corner of\
windshield. The eighth character identifies the engine model.
Engine model number is stamped on front upper edge of
cylinder block (below cylinder head) or on vehicle information plate
on firewall. Engine serial number is stamped near the engine model
number.
ENGINE IDENTIFICATION CODES TABLE









\









\









\









\









\









\

Application Engine Model Engine Code
3.0L V6 SOHC
Montero ............... 6G72 .................... S
Pickup ................ 6G72 .................... S
3.0L V6 DOHC
3000GT
Non-Turbo ............ 6G72 .................... B
Turbo ................ 6G72 .................... C









\









\









\









\









\









\

ADJUSTMENTS
VALVE CLEARANCE ADJUSTMENT
NOTE: Hydraulic lash adjusters are set into rocker arms (SOHC) or
cylinder head (DOHC). No adjustment is required.
REMOVAL & INSTALLATION
NOTE: For reassembly reference, label all electrical connectors,
vacuum hoses and fuel lines before removal. Also place
mating marks on engine hood and other major assemblies
before removal.
FUEL PRESSURE RELEASE
Perform these steps to release fuel system pressure:
* Disconnect fuel pump harness connector at fuel tank.
* Start engine. After it stalls, turn ignition switch to OFF
position.
* Disconnect battery (-) terminal, and reconnect fuel pump
harness connector.

pulley and mounting bracket. Remove A/C compressor with hoses
connected, and remove mounting bracket. Remove cooling fan bracket
assembly. Note location and length of bolts for reassembly reference.
3) Remove No. 1 and No. 2 timing belt upper outer covers and
gaskets. See Fig. 7. Remove timing belt lower outer cover and gaskets.
Using Holder (MB998747) and a used "V" belt, remove crankshaft pulley
bolt. Remove crankshaft pulley.
NOTE: "V" belt will be damaged by tool. DO NOT use engine "V"
belt to hold crankshaft pulley unless replacing belt.
4) Remove flange. See Fig. 7. Rotate crankshaft and align all
timing marks. See Fig. 8. Loosen belt tensioner bolt, and rotate belt
tensioner counterclockwise to release belt tension.
5) If reusing timing belt, place arrow on belt to indicate
direction of belt rotation. Remove timing belt and belt tensioner. If
camshaft sprocket requires removal, install Holder (MB990775) on
camshaft sprocket. Remove retaining bolt and camshaft sprocket. Remove
rear timing belt cover (if required).
Fig. 7: Exploded View of Timing Belt Components (SOHC Is Similar)
Courtesy of Mitsubishi Motor Sales of America, Inc.

Fig. 8: Aligning Timing Marks (SOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc.
Inspection (Montero & Pickup)
Inspect timing belt for wear on edges of drive teeth. Inspect
belt for oil contamination, cracks, separation, worn or missing teeth
and hardened back surface. Replace belt if worn, damaged or
contaminated. Inspect belt tensioner for smooth rotation. Replace if
defective.
Installation (Montero & Pickup)
1) Install rear timing belt cover. Tighten bolts to
specification. See TORQUE SPECIFICATIONS (MONTERO & PICKUP) table at
end of article. Install camshaft sprockets (if removed). Using holder,\
hold camshaft and tighten retaining bolt to specification.
2) Install belt tensioner and spring. Ensure spring is
secured on pin of water pump and engaged in hole of belt tensioner
with hook of spring pointing from cylinder block.
3) Rotate belt tensioner counterclockwise as much as
possible, and temporarily tighten bolt. Align all timing marks with
No. 1 cylinder at TDC of compression stroke. See Fig. 8.
4) Install timing belt on crankshaft sprocket and then left
camshaft sprocket with all slack removed from tension side of belt.
Route timing belt onto water pump pulley, right camshaft sprocket and
tensioner. Remove any slack from belt by rotating left and then right
camshaft sprockets counterclockwise.
5) Ensure belt is installed in original direction of rotation
and all timing marks are aligned. Install flange on crankshaft. Loosen
belt tensioner bolts slightly, and allow tensioner to apply belt
tension.
6) Using Crankshaft Socket (MD998716), rotate crankshaft 2

revolutions clockwise. DO NOT rotate counterclockwise. Realign all
timing marks. Tighten belt tensioner bolts to specification. Using
belt tension gauge, measure belt tension halfway between crankshaft
sprocket and camshaft sprocket on side opposite belt tensioner.
7) Belt tension should be 57.3-83.8 lbs. (26-38 kg). To
install remaining components, reverse removal procedure. Install
proper length bolts in timing belt covers. See Fig. 9. Tighten bolts
to specification. See TORQUE SPECIFICATIONS (MONTERO & PICKUP) table.
Fig. 9: Identifying Timing Belt Cover Bolt Lengths (MONTERO & PICKUP)\
Courtesy of Mitsubishi Motor Sales of America, Inc.

Fig. 10: Engine Support Bracket Bolt Removal Sequence (3000GT)
Courtesy of Mitsubishi Motor Sales of America, Inc.
NOTE: Apply spray lubricant on reamer bolt during removal as bolt
is sometimes seized in engine support bracket.
Removal (3000GT)
1) Remove lower splash shields. Remove cruise control
actuator (if equipped). Remove all drive belts. Disconnect electrical
connector at power steering pump. Remove A/C tensioner pulley and
mounting bracket.
2) Remove power steering pump with hoses connected, and wire
aside. Support engine. Remove front engine mount through bolt and
front engine mount. Remove timing belt No. 1 upper outer cover and
gaskets. See Fig. 7.
3) Remove engine support bracket bolts in proper sequence.
See Fig. 10 . Remove engine support bracket. Remove cover cap and
timing belt No. 2 upper outer cover and gaskets. Using Holder
(MB990767) and Adapter Bolts (MD998719), remove crankshaft pulley.
4) Remove lower outer cover, gaskets and flange. See Fig. 7.
Rotate crankshaft and align all timing marks. See Fig. 8. Loosen belt
tensioner bolt, and rotate belt tensioner counterclockwise to release
belt tension.
5) If reusing timing belt, place arrow on belt to indicate
direction of belt rotation. Remove timing belt and belt tensioner.
6) If camshaft sprocket requires removal, install Holder
(MB990767) with Adapter Bolts (MD998719) on camshaft sprocket. Remov\
e
camshaft sprocket bolt and camshaft sprocket. Remove rear timing belt
cover (if required).
Inspection (3000GT)
Inspect timing belt for wear on edges of drive teeth. Inspect
belt for oil contamination. Replace belt if damaged or contaminated.

Inspect belt tensioner for smooth rotation. Replace if defective.
Installation
1) Install rear timing belt cover. Tighten bolts to
specification. See TORQUE SPECIFICATIONS (3000GT) table at end of
article. Install camshaft sprockets (if removed). Using holder, hold
camshaft and tighten camshaft sprocket bolt to specification.
2) Install belt tensioner and spring. Ensure spring is
secured on pin of water pump and engaged in hole of belt tensioner
with hook of spring pointing from cylinder block.
3) Rotate belt tensioner counterclockwise as much as
possible, and temporarily tighten bolt. Align all timing marks with
No. 1 cylinder at TDC of compression stroke. See Fig. 8.
4) Install timing belt on crankshaft sprocket, rear cylinder
bank camshaft sprocket, water pump pulley, front cylinder bank
camshaft sprocket and timing belt tensioner. Ensure belt is installed
in original direction of rotation and all timing marks are aligned.
Install flange on crankshaft. Loosen belt tensioner bolts slightly,
and allow tensioner to apply belt tension.
5) Using Crankshaft Socket (MD998716), rotate crankshaft 2
revolutions clockwise. DO NOT rotate counterclockwise. Realign all
timing marks. Tighten belt tensioner bolts to specification. See
TORQUE SPECIFICATIONS (3000GT) table. Using belt tension gauge,
measure belt tension halfway between crankshaft sprocket and camshaft
sprocket on side opposite belt tensioner.
6) Belt tension should be 46.3-63.3 lbs. (21-29 kg). To
install remaining components, reverse removal procedure. Install
proper length bolts in timing belt covers and engine support bracket.
See Figs. 9 and 10. Tighten bolts to specification. See TORQUE
SPECIFICATIONS (3000GT) table.
NOTE: Engine support bracket reamer bolt must be tightened slowly
while spraying lubricant on bolt.
Fig. 11: Identifying Timing Belt Cover Bolt Length (SOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc.
Removal (DOHC)
1) Remove lower splash shields. Remove cruise control

article.
2) Place automatic tensioner assembly in a soft-faced vise.
Squeeze rod back into automatic tensioner in small increments until
both rod and housing holes are aligned. Install a .055" (1.39 mm)
diameter wire through both holes.
3) Remove automatic tensioner from vise, and install assembly
with wire installed. Install crankshaft sprocket (if removed). Align
timing marks on crankshaft and camshaft sprockets. See Fig. 13.
CAUTION: Turning camshaft sprockets while No. 1 cylinder is at TDC
may damage valve and piston. Use care when aligning timing
marks.
4) To lower No. 1 piston from TDC and prevent valve and
piston contact, turn crankshaft back 3 sprocket teeth (measured at
timing mark). Starting with front bank of cylinders, ensure intake and
exhaust camshaft timing marks are not within shaded area of figure.
See Fig. 14 .
When camshaft sprocket timing marks are in indicated area,
camshaft is under valve spring pressure and may rotate suddenly,
pinching hand between sprockets. Use care when aligning timing marks.
Fig. 14: Adjusting Timing Marks to Prevent Valve & Piston Damage
(DOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc.
5) If camshaft sprocket timing mark is within indicated area,
carefully rotate camshaft sprocket until timing mark is located in
nearest safe area. See Fig. 14.
6) Rotate either camshaft sprocket clockwise to align timing
marks as shown in Fig. 15. If camshaft sprocket is turned past timing
mark, turn it counterclockwise to realign it. Repeat procedure for

other front bank camshaft sprocket.
Fig. 15: Aligning Timing Marks Final Alignment (DOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc.
7) Repeat steps 4)-6) for rear cylinder bank camshafts. Alig\
n
crankshaft timing mark. Install timing belt on sprockets in sequence.
See Fig. 16 . Use spring-type paper clips to secure belt on sprockets.
Use offset box-end wrenches on camshaft sprocket bolts to keep
camshafts from turning during belt installation.
NOTE: If necessary, crankshaft sprocket may be turned one tooth
counterclockwise to aid belt installation.

Fig. 16: Installing Timing Belt (DOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc.
8) Rotate timing belt tensioner pulley until pin holes are
located above center bolt. See Fig. 17. Push tensioner pulley against
belt, and temporarily tighten center bolt. Ensure all timing marks are
still aligned, and remove clips.
Fig. 17: Adjusting Timing Belt Tensioner (DOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc.
9) Rotate crankshaft 1/4 revolution counterclockwise. Rotate
crankshaft clockwise until timing marks are realigned. Loosen

tensioner center bolt. Using Tensioner Pulley Socket (MD998767) and
torque wrench, apply 84 INCH lbs. (9.5 N.m). See Fig. 17. Retighten
center bolt to specification. See TORQUE SPECIFICATIONS (3000GT) table\
at end of article. Ensure tensioner pulley does not rotate while
tightening center bolt.
10) Ensure wire installed in automatic tensioner can be
easily removed and installed. Rotate crankshaft 2 revolutions
clockwise. Wait 5 minutes. Ensure wire can still be removed and
installed easily or automatic tensioner rod projects from tensioner
body .150-.177" (3.8-4.5 mm).
11) If rod projection is not to specification, repeat steps
9) and 10). To complete installation, reverse removal procedure.
Install proper length bolts in timing belt covers. Install bolts into
engine support bracket in reverse order of removal sequence. See
Fig. 10 . Tighten bolts to specification. See TORQUE SPECIFICATIONS
(3000GT) table.
NOTE: Engine support bracket reamer bolt must be tightened slowly
while spraying lubricant on bolt.
CAMSHAFT & ROCKER ARMS
Removal (SOHC)
1) Remove PCV valve and breather hoses. Remove timing belt,
camshaft sprocket and rear timing belt cover. See TIMING BELT under
REMOVAL & INSTALLATION. Remove rocker covers and gaskets. Remove
circular packing from rear of camshafts.
2) Remove camshaft oil seal from front of cylinder head or
distributor adapter. Remove distributor adapter and "O" ring. Install
Valve Lash Adjuster Holder (MD998443) on rocker arm. See Fig. 18. Note
arrow marks on bearing caps and cylinder head. See Fig. 19.
3) Bearing cap location number is stamped on front side of
bearing cap. Remove bearing cap bolts. Keep components in order for
reassembly reference. Remove rocker arm assembly. Remove camshaft from
cylinder head.
Fig. 18: Installing Valve Lash Adjuster Holder (SOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc.