1991 MITSUBISHI MONTERO engine oil

* Wrap shop towels around fuel return and high pressure hoses
to prevent fuel splashing on engine. Disconnect fuel return
hose and high pressure fuel hose to drain any residual fuel.
ENGINE
Removal (Montero & Pickup)
1) Remove hood. Drain cooling system, and remove radiator.
Remove skid plate and splash shields. Release fuel system pressure.
See FUEL PRESSURE RELEASE under REMOVAL & INSTALLATION. Disconnect
negative battery cable.
2) Remove air cleaner ducts. Remove accessory drive belts.
Remove and support A/C compressor and power steering pump. DO NOT
disconnect hoses from compressor or pump. Disconnect oil cooler hoses.
Cover fuel hose using shop towel, and disconnect high pressure fuel
hose and "O" ring. Remove fuel return hose.
3) Label and disconnect all vacuum hoses. Disconnect cooling
system hoses. Label and disconnect all electrical connections from
engine. Remove heat shield from motor mounts. Remove motor mount
bolts. Ensure all hoses and wires are disconnected and set aside.
4) Disconnect exhaust pipe from exhaust manifolds. Remove
starter. Attach engine hoist to engine. Support transmission.
Disconnect engine from transmission. See appropriate article in
CLUTCHES or TRANSMISSION SERVICING. Remove engine.
Installation (Montero & Pickup)
To install, reverse removal procedure. Install new "O" ring
on fuel line. Install new exhaust gaskets and nuts. See TORQUE
SPECIFICATIONS (MONTERO & PICKUP) table at end of article. Adjust
fluid levels.
Removal (3000GT)
1) Release fuel pressure. See FUEL PRESSURE RELEASE under
REMOVAL & INSTALLATION. Remove hood. Remove cruise control vacuum pump
and linkage. On turbo models, remove necessary turbo air intake hoses
and pipes. On all other models, remove air cleaner hoses.
2) On all models, drain cooling system. Drain engine oil and
transaxle oil. Remove heater hoses and radiator hoses. Remove
transaxle assembly. See appropriate article in CLUTCHES or
TRANSMISSION SERVICING.
3) Remove radiator. Label and disconnect all vacuum hoses.
Label and disconnect all electrical connections and harnesses from
engine. Remove accessory drive belts.
4) Remove and support A/C compressor and power steering pump.
DO NOT disconnect hoses from compressor or pump. Cover fuel hose using
shop towel, and disconnect high pressure fuel hose and "O" ring.
Remove fuel return hose.
5) On turbo models, disconnect oil cooler and vacuum hoses.
On all models, remove motor mount bolts and brackets. Ensure all hoses
and wires are disconnected and set aside. Attach engine hoist to
engine. Remove engine.
Installation
To install, reverse removal procedure. Install new "O" ring
on fuel line. Install new exhaust gaskets and nuts. See TORQUE
SPECIFICATIONS (3000GT) table at end of article. Adjust fluid levels.
UPPER INTAKE MANIFOLD
Removal (Montero & Pickup)
1) Remove air intake hose. See Fig. 1. Remove accelerator
cable adjusting bolts. On models equipped with automatic transmission,
remove throttle control cable. On all models, remove accelerator

cable. Label and disconnect all vacuum hoses from throttle body and
upper intake manifold.
2) Disconnect O2 sensor connector. Remove EGR pipe and
gasket. Remove ignition coil. Remove engine oil filler neck bracket.
Remove throttle body, leaving coolant hoses connected. Remove throttle
body gasket. Remove upper intake manifold plenum mounting bolts and
nuts.
3) If necessary, remove EGR valve and pipe. Remove upper
intake manifold plenum brackets. Remove upper intake manifold and
gasket.
Inspection & Installation (Montero & Pickup)
Clean all gasket mating surfaces. Inspect for damage and
cracks on all mounting surfaces. To install, reverse removal procedure
using new gaskets. Tighten bolts and nuts to specification. See TORQUE
SPECIFICATIONS (MONTERO & PICKUP) table at end of article.
Fig. 1: Exploded View of Upper Intake Manifold & Components (DOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc

install, reverse removal procedure using new gaskets and "O" rings.
Coat "O" ring with fuel before installation.
2) Install lower intake manifold gasket with adhesive side
toward intake manifold and gasket protrusions facing outboard of
engine. Tighten bolts and nuts to specification. See appropriate
TORQUE SPECIFICATIONS table at end of article. Check for fuel leaks.
TURBOCHARGER
Removal (Front)
1) Drain coolant, and remove radiator. Disconnect exhaust
pipe from turbo. Remove all air intake pipes. Note match marks and
installation depth on air pipes and hoses for reinstallation. Remove
serpentine drive belt. Remove alternator. Remove A/C compressor and
bracket, and support aside.
2) Remove O2 sensor. Remove dipstick assembly and turbo heat
shield. Disconnect turbo coolant feed and return lines. Disconnect
turbo oil feed and return lines. Remove turbocharger assembly.
Removal (Rear)
1) Drain coolant. Remove battery. Disconnect accelerator
cable at bracket and throttle body. Disconnect exhaust pipe from
turbo. Remove all air intake pipes and heat shields. Disconnect
accelerator cable at pedal.
2) Remove clutch booster vacuum hose. Remove O2 sensor.
Remove EGR pipe and turbo heat shield. Disconnect turbo coolant feed
and return lines. Disconnect turbo oil feed and return lines. Remove
turbocharger assembly.
CAUTION: DO NOT allow foreign material into turbocharger air intakes
or coolant and oil passages.
Inspection (Front & Rear)
1) Inspect turbocharger for oil leakage. Check turbine and
compressor wheels for cracks and other damage. Both wheels should turn
easily by hand.
2) Apply 6.8 psi (61 kPa) vacuum to wastegate diaphragm.
Ensure wastegate operates and diaphragm holds vacuum pressure. Use
care when cleaning gasket surfaces so no foreign material enters
turbocharger oil, coolant and air passages.
Installation (Front & Rear)
Refill turbocharger with clean engine oil through oil pipe
installation hole. To complete installation, reverse removal
procedure. Align match marks, and install air pipes and hoses to
proper depth.
EXHAUST MANIFOLDS
Removal (Montero & Pickup)
1) Remove splash shields. Remove O2 sensor. Remove exhaust
pipe-to-manifold nuts. Lower exhaust pipe, and remove gasket. Remove
heat protector. To remove right exhaust manifold, remove air duct,
engine lift bracket and alternator bracket.
2) To remove left exhaust manifold, remove EGR pipe and
gasket. Remove front intake manifold plenum bracket. Remove exhaust
manifolds and gaskets.
Inspection (Montero & Pickup)
Clean all gasket mating surfaces. Inspect for damage and
cracks on all mounting surfaces. Check mounting surfaces of manifold
and cylinder head for warpage. Repair or replace components if warpage
exceeds .012" (.30 mm).

surfaces. Resurface head if warpage exceeds specification. See
CYLINDER HEAD (SOHC) table under ENGINE SPECIFICATIONS at end of
article. Replace cylinder head if it is not within specification after
resurfacing.
Installation (SOHC)
1) Ensure mating surfaces are clean and dry. Note
identification mark located on front of head gasket. Identification
marks are: "R" for SOHC, "2DN" for DOHC non-turbocharged and "2DT" for
DOHC turbocharged engine. Install head gasket with identification mark
toward timing belt side of engine and facing upward. Ensure all holes
are aligned.
NOTE: Install head gasket with identification mark toward timing
belt side of engine and facing upward. Ensure all holes
align. Install washers on head bolts with chamfered side
toward bolt head.
2) Install cylinder head and bolts. Ensure washers are
installed on head bolts with chamfered side toward bolt head. Using
proper sequence, tighten bolts to specification in 2-3 steps. See
Fig. 5 . See appropriate TORQUE SPECIFICATIONS table at end of article.
3) Apply sealant to rocker cover sealing surfaces before
installation. See Fig. 6. Ensure rocker cover gasket projections are
aligned with notches in rocker cover. Coat all "O" rings with oil, and
install a new "O" ring on distributor adapter and oil dipstick tube.
4) Coat camshaft area with oil prior to installing
distributor adapter. To complete installation, reverse removal
procedure. Tighten bolts and nuts to specification. See appropriate
TORQUE SPECIFICATIONS table. After engine reaches normal operating
temperature, allow engine to cool, and retighten cylinder head bolts.
Fig. 6: Applying Sealant to Rocker Cover (SOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc.
Removal (DOHC)
1) Drain cooling system. Remove upper and lower intake
manifolds and brackets. See UPPER INTAKE MANIFOLD and LOWER INTAKE
MANIFOLD under REMOVAL & INSTALLATION.
2) Remove turbocharger(s) (if equipped). See TURBOCHARGER
under REMOVAL & INSTALLATION. Remove heat shields from exhaust
manifolds. Remove exhaust manifolds. See EXHAUST MANIFOLDS under
REMOVAL & INSTALLATION.
3) Remove spark plug wires and ignition coils. Remove rocker
cover and gasket. Remove timing belt and timing belt inner covers. See

TIMING BELT under REMOVAL & INSTALLATION. Remove intake camshaft
sprockets.
4) Remove coolant manifold and coolant inlet pipe. Using
Socket (MD998051), remove cylinder head bolts. Remove cylinder head
and camshaft assemblies. Note direction of washer installation on head
bolts.
Inspection (DOHC)
Check cylinder head height. Check warpage at gasket and
manifold surfaces. Resurface head if warpage exceeds specification.
See CYLINDER HEAD (DOHC) table under ENGINE SPECIFICATIONS at end of
article. After resurfacing, recheck cylinder head height. Replace
cylinder head if it is not within specification.
Installation (DOHC)
1) Ensure mating surfaces are clean and dry. Note
identification mark located on front of head gasket. Identification
marks are: "R" for SOHC, "2DN" for DOHC non-turbocharged and "2DT" for
DOHC turbocharged engine. Install head gasket with identification mark
toward timing belt side of engine and facing upward. Ensure all holes
are aligned.
NOTE: Install head gasket with identification mark toward timing
belt side of engine and facing upward. Ensure all holes
align. Install washers on head bolts with chamfered side
toward bolt head.
2) Install cylinder head and bolts. Ensure washers are
installed on head bolts with chamfered side toward bolt head. Using
proper sequence, tighten bolts to specification in 2-3 steps. See
Fig. 5 . See TORQUE SPECIFICATIONS (3000GT) table at end of article. On
turbocharger equipped engines, back off head bolts once, and repeat
tightening procedure.
3) To reinstall camshaft sprocket, hold hexagonal area of
camshaft using wrench while tightening sprocket bolt. Tighten rocker
cover bolts in a crisscross pattern. Start at 4 corners of rocker
cover and move toward center.
NOTE: Rocker cover bolts are color coded. Front cylinder bank
bolts are black; rear cylinder bank bolts are green.
4) To complete installation, reverse removal procedure.
Tighten bolts and nuts to specification. See TORQUE SPECIFICATIONS
(3000GT) table.
FRONT CRANKSHAFT OIL SEAL
Removal & Installation
Remove timing belt and crankshaft sprocket. See TIMING BELT
under REMOVAL & INSTALLATION. Pry oil seal from oil pump. To install,
coat seal lip with grease. Using Seal Installer (MD998717), install
seal in oil pump. Install remaining components. See appropriate TORQUE
SPECIFICATIONS table at end of article.
TIMING BELT
Removal (Montero & Pickup)
1) Drain cooling system. Disconnect upper radiator hose.
Remove upper radiator shroud. Remove cooling fan and fan clutch
assembly. Remove cooling fan pulley. Remove all drive belts. Remove
power steering pump with pressure and return hoses connected, and set
aside.
2) Remove power steering pump brackets. Remove A/C tensioner

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.

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.

2) Inspect camshaft and distributor gear for damage. Measure
camshaft end play, journal diameter and lobe height. Replace camshaft
if it is not within specification. See CAMSHAFT (SOHC) table under
ENGINE SPECIFICATIONS at end of article.
3) Coat components with oil. Reassemble rocker arms, springs
and bearing caps. Install bearing caps with identification number
toward camshaft sprocket. Ensure oil holes and notch of shafts are
properly positioned. See Fig. 19.
ROCKER ARM & SHAFT SPECIFICATIONS TABLE (SOHC)









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Application In. (mm)
Oil Clearance ................. ( 1).0004-.0016 (.010-.041)
Rocker Arm I.D. ............................ .7444 (18.91)
Rocker Arm Shaft O.D. ...................... .7440 (18.90)
Spring Free Length ......................... 2.173 (55.19)
( 1) - Maximum clearance is .0039" (.099 mm).









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Fig. 20: Installing Rocker Arm Shafts (SOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc.
Installation
1) Coat camshaft with oil, and install in cylinder head.