1991 MITSUBISHI MONTERO sensor

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

released before disconnecting fuel lines.
Removal
1) Release fuel pressure. See FUEL PRESSURE RELEASE under
REMOVAL & INSTALLATION. Remove upper intake manifold. See UPPER INTAKE
MANIFOLD under REMOVAL & INSTALLATION.
2) Drain cooling system. Remove high pressure and return fuel
lines. Cover fuel lines using shop towel during removal as some fuel
may be retained. Remove vacuum hose from pressure regulator.
Disconnect injector harness from injectors.
3) Remove fuel delivery pipe, fuel injectors and pressure
regulator. See Fig. 3. DO NOT allow injectors to fall from delivery
pipe during removal. Remove vacuum hose and pipe assembly.
4) On Montero & Pickup, disconnect coolant temperature
sending unit, coolant temperature switch (A/C equipped), coolant
temperature sensor and thermoswitch (A/T equipped). Disconnect upper
radiator and coolant by-pass hoses. Disconnect heater pipe. On all
models, remove intake manifold and gasket.
Fig. 3: Exploded View of Lower Intake Manifold & Components
Courtesy of Mitsubishi Motor Sales of America, Inc.
Inspection & Installation
1) Inspect for damage and cracks on all mounting surfaces. To

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).

Removal (SOHC)
1) Drain cooling system. Remove upper and lower intake
manifolds and brackets. See UPPER INTAKE MANIFOLD and LOWER INTAKE
MANIFOLD under REMOVAL & INSTALLATION. Remove spark plug wires. Remove
splash shields.
2) Disconnect O2 sensor. Disconnect exhaust pipe from exhaust
manifold, and support to crossmember using wire. Remove heat shields
and exhaust manifolds. See EXHAUST MANIFOLDS under REMOVAL &
INSTALLATION.
3) Remove distributor (left or rear head). Remove timing bel\
t
outer covers, camshaft sprockets, timing belt and timing belt inner
covers. See TIMING BELT under REMOVAL & INSTALLATION. Remove accessory
bracket bolts from front of cylinder head. Remove rocker cover and
gasket.
4) Using Socket (MD998051), loosen cylinder head bolts in 2-\
3
steps using proper sequence. See Fig. 5. Remove cylinder head and
camshaft assemblies. Note direction of washer installation on head
bolts.
NOTE: Cylinder head bolts must be loosened in 2-3 steps using
proper sequence to prevent cylinder head warpage and
cracking.
Fig. 5: Cylinder Head Bolt Removal & Tightening Sequence
Courtesy of Mitsubishi Motor Sales of America, Inc.
Inspection (SOHC)
Check cylinder head height and warpage at gasket and manifold

actuator (if equipped). Remove all drive belts. Remove alternator.
Remove drive belt tensioner assembly.
2) Using Holder (MB990767) and Adapter Bolts (MD998754),
remove crankshaft pulley. See Fig. 12. Disconnect brake fluid level
sensor. Remove upper timing belt covers. Support engine. Remove front
engine mount through bolt and front engine mount.
NOTE: Apply spray lubricant on reamer bolt during removal as bolt
is sometimes seized in engine support bracket.
Fig. 12: Exploded View of Timing Belt Components (DOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc.
3) Remove drive belt idler pulley. Remove engine support
bracket bolts in proper sequence. See Fig. 10. Remove engine support

Install valve lash adjusters and valve lash adjuster holders (if
removed). See Fig. 18.
2) Apply 3M Sealant (4171) to designated areas of cylinder
head. See Fig. 19. Use care so sealant does not get on camshaft or
camshaft bearing journals. Install rocker arm assembly. Ensure arrow
on bearing cap faces same direction as arrow on cylinder head. See
Fig. 19 . Tighten bearing cap bolts to specification. See appropriate
TORQUE SPECIFICATIONS table at end of article. Remove valve lash
adjuster holders.
3) Coat camshaft oil seal area with oil. Using Seal Installer
(MD998713), install camshaft oil seal. Using Circular Packing
Installer (MD998306), install circular packing to press-in depth of .
02" (.5 mm).
4) Apply Three Bond (1212D) sealant to rocker cover sealing
surfaces before installation. See Fig. 6. Coat new "O" ring with oil,
and install on distributor adapter (if removed).
5) Coat camshaft area with oil before installing distributor
adapter. To complete installation, reverse removal procedure. Tighten
bolts to specification. See appropriate TORQUE SPECIFICATIONS table.
Removal (DOHC)
1) Remove UPPER INTAKE MANIFOLD and LOWER INTAKE MANIFOLD as
necessary. See UPPER INTAKE MANIFOLD and LOWER INTAKE MANIFOLD under
REMOVAL & INSTALLATION. Remove timing belt, camshaft sprockets and
rear timing belt covers. See TIMING BELT under REMOVAL & INSTALLATION.
2) Remove center cover and spark plug wires. Remove PCV and
breather hoses. Remove rocker covers and gaskets. Remove crank angle
sensor adapter. Remove front and rear camshaft bearing caps along with
seals and circular packings.
3) Remove remaining camshaft bearing caps in sequence: No. 2,
No. 4 and No. 3. Remove camshaft, rocker arms and lash adjusters. Mark
component location for reassembly reference.
Inspection (DOHC)
Inspect rocker arm for damaged roller and flaking. Inspect
camshaft for damage. Measure camshaft end play, journal diameter and
lobe height. Replace camshaft if it is not within specification. See
CAMSHAFT (DOHC) table in ENGINE SPECIFICATIONS at end of article.
Installation (DOHC)
1) Coat components with oil. Install lash adjusters and
rocker arms. Bring No. 1 cylinder to TDC. Ensure intake and exhaust
camshafts are installed correctly. Intake camshaft is marked with a
"V" and exhaust camshaft is marked with a "C" on hexagon section.
Position camshaft dowels as shown. See Fig. 21.
NOTE: If cylinder head is off vehicle, support cylinder head at
least .39" (10 mm) above work surface to prevent valve
damage while installing camshaft bearing caps.
Fig. 21: Installing Camshafts & Bearing Caps (DOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc.
2) Install camshaft bearing caps in sequence: No. 3, No. 4

and No. 2. Install bearing caps with front mark arrow facing the same
direction as similar mark on cylinder head beside bearing journal.
Note bearing cap number and identification mark ("I" for intake
camshaft and "E" for exhaust). See Fig. 22.
3) Install front and rear bearing caps. Tighten bearing cap
bolts to specification. See TORQUE SPECIFICATIONS (3000GT) table at
end of article. Coat camshaft oil seal area with oil. Using Seal
Installer (MD998761), install camshaft oil seal. Using Circular
Packing Installer (MD998761), install circular packing.
4) Install crankshaft angle sensor adapter. To complete
installation, reverse removal procedure. Tighten bolts to
specification. See TORQUE SPECIFICATIONS table.
REAR CRANKSHAFT OIL SEAL
Removal
Remove transaxle/transmission. See appropriate article in
TRANSMISSION SERVICING or CLUTCHES. Remove flywheel or drive plate.
Remove rear oil seal case. Pry seal from seal case.
Installation
To install, coat seal lip with oil. Using Seal Installer
(MD998718), install seal in seal case. Apply sealant to sealing
surface of seal case. Install seal case. Install flywheel or drive
plate. Tighten bolts to specification. See appropriate TORQUE
SPECIFICATIONS table at end of article. To complete installation,
reverse removal procedure.
WATER PUMP
Removal
Drain cooling system. Remove timing belt and crankshaft
sprocket. See TIMING BELT under REMOVAL & INSTALLATION. Remove coolant
pipes to water pump (if required). Remove water pump bolts, noting
length and location for reassembly reference. Remove water pump.
Installation
To install, reverse removal procedure using new gasket and
"O" rings. Coat all "O" rings with water before installation. Install
water pump and gasket. Tighten bolts to specification. See appropriate
TORQUE SPECIFICATIONS table at end of article.
OIL PAN
Removal (Montero)
1) Remove hood. Remove skid plate and lower covers. Raise and
support vehicle. Disconnect and remove exhaust pipe from exhaust
manifolds. Drain engine oil. Remove starter cover and starter. Remove
oil pressure sending unit connector. Remove front suspension
crossmember.
2) Remove transmission stays. Remove ground cable and motor
mount heat shields. Attach engine hoist. Remove motor mount bolts.
Raise engine, and insert a 1" wood spacer between front insulator and
mounts. Lower engine onto wood blocks.
3) Raise vehicle using a hoist. Remove oil pan bolts. Using
Seal Cutter (MD998727), separate oil pan from cylinder block. Remove
pan from vehicle.
Removal (Pickup)
1) Remove skid plate and lower covers. Raise and support
vehicle. Drain engine oil. Using Steering Linkage Puller (C-3894-A or
MB990635), disconnect relay rod from idler arm and steering box.
2) Remove oil pan bolts. Using Seal Cutter (MD998727),

separate oil pan from cylinder block. Remove pan from vehicle.
Removal (3000GT)
1) Raise and support vehicle. Remove engine undercovers.
Drain engine oil. Disconnect O2 sensor connector. Remove front exhaust
pipe from manifolds. On All-Wheel Drive (AWD) models, drain transfer
assembly. Remove front air dam. Remove AWD drive shaft and transfer
assembly.
2) On turbocharged models, remove oil return lines from oil
pan. On all models, remove starter. Remove crossmember and transaxle
stays. Remove bellhousing cover. Remove oil pan bolts. Using Seal
Cutter (MD998727), separate oil pan from cylinder block. Remove pan
from vehicle.
Inspection (All Models)
Clean sealant from oil pan mating surface on engine block and
oil pan. Check oil pan for cracks and damage. Check sealing surface
for damage and deformation. Inspect oil pick-up screen for damage.
Installation (All Models)
1) To install, reverse removal procedure. Apply sealant to
oil pan flange in a continuous .16" (4 mm) diameter bead. See Fig. 22.
Install oil pan within 15 minutes of applying sealant.
2) Tighten bolts to specification in proper sequence. See
appropriate TORQUE SPECIFICATIONS table at end of article. Wait at
least 30 minutes before adding oil and starting engine. On AWD models,
refill transfer assembly with GL-4 hypoid gear oil. On all models,
complete installation by reversing removal procedure.
Fig. 22: Sealant Application & Oil Pan Bolt Tightening Sequence
Courtesy of Mitsubishi Motor Sales of America, Inc.
OVERHAUL