1997 SUBARU LEGACY low oil pressure

TROUBLE
Engine will not start.
Rough idle and engine stall
Low output, hesitation and poor acceleration
Surging
Engine does not return to idle.
Dieseling (Run-on)
After burning in exhaust system
Knocking
Excessive engine oil consumption
Excessive fuel consumption Starter does not turn.
Initial combustion does not occur.
Initial combustion occurs.
Engine stalls after initial combustion.
LUBRICATION SYSTEM
22 3 3Incorrect oil pressure
2Loosened oil pump attaching bolts and defective
gasket
2Defective oil filter seal
2Defective crankshaft oil seal
32Defective rocker cover gasket
2Loosened oil drain plug or defective gasket
2Loosened oil pan fitting bolts or defective oil pan
COOLING SYSTEM
33221Overheating
333Over cooling
OTHERS
113 3Malfunction of Evaporative Emission Control
System
21Stuck or damaged throttle valve
322 2Accelerator cable out of adjustment
77
2-3DIAGNOSTICS
1. Engine Trouble in General

2. Engine Noise
Type of sound Condition Possible cause
Regular clicking soundSound increases as engine
speed increases.Valve mechanism is defective.
Incorrect valve clearance
Worn valve rocker
Worn camshaft
Broken valve spring
Heavy and dull clankOil pressure is low.Worn crankshaft main bearing
Worn connecting rod bearing (big end)
Oil pressure is normal.Loose flywheel mounting bolts
Damaged engine mounting
High-pitched clank
(Spark knock)Sound is noticeable when
accelerating with an overload.Ignition timing advanced
Accumulation of carbon inside combustion chamber
Wrong spark plug
Improper gasoline
Clank when engine speed is
medium (1,000 to 2,000 rpm).Sound is reduced when fuel
injector connector of noisy
cylinder is disconnected.
(NOTE*)Worn crankshaft main bearing
Worn bearing at crankshaft end of connecting rod
Knocking sound when engine
is operating under idling speed
and engine is warm.Sound is reduced when fuel
injector connector of noisy
cylinder is disconnected.
(NOTE*)Worn cylinder liner and piston ring
Broken or stuck piston ring
Worn piston pin and hole at piston end of connecting rod
Sound is not reduced if each
fuel injector connector is
disconnected in turn. (NOTE*)Worn camshaft journal bore in crankcase
Squeaky sound—Insufficient generator lubrication
Rubbing sound—Defective generator brush and rotor contact
Gear scream when starting
engine—Defective ignition starter switch
Worn gear and starter pinion
Sound like polishing glass with
a dry cloth—Loose drive belt
Defective engine coolant pump shaft
Hissing sound—Loss of compression
Air leakage in air intake system, hoses, connections or
manifolds
Timing belt noise—Loose timing belt
Belt contacting case/adjacent part
Valve tappet noise—Incorrect valve clearance
NOTE*:
When disconnecting fuel injector connector, Malfunction Indicator Light (CHECK ENGINE light) illuminates and trouble code is stored in
ECM memory.
Therefore, carry out the CLEAR MEMORY MODE and INSPECTION MODE after connecting fuel injector connector. (Ref. to 2-7 On-Board
Diagnostics II System.)
78
2-3DIAGNOSTICS
2. Engine Noise

TROUBLE
Engine will not start.
Rough idle and engine stall
Low output, hesitation and poor acceleration
Surging
Engine does not return to idle.
Dieseling (Run-on)
After burning in exhaust system
Knocking
Excessive engine oil consumption
Excessive fuel consumption Starter does not turn.
Initial combustion does not occur.
Initial combustion occurs.
Engine stalls after initial combustion.
LUBRICATION SYSTEM
22 3 3Incorrect oil pressure
2Loosened oil pump attaching bolts and defective
gasket
2Defective oil filter seal
2Defective crankshaft oil seal
32Defective rocker cover gasket
2Loosened oil drain plug or defective gasket
2Loosened oil pan fitting bolts or defective oil pan
COOLING SYSTEM
33221Overheating
333Over cooling
OTHERS
113 3Malfunction of Evaporative Emission Control
System
21Stuck or damaged throttle valve
322 2Accelerator cable out of adjustment
79
2-3bDIAGNOSTICS
1. Engine Trouble in General

2. Engine Noise
Type of sound Condition Possible cause
Regular clicking soundSound increases as engine
speed increases.Valve mechanism is defective.
Incorrect valve clearance
Worn camshaft
Broken valve spring
Heavy and dull clankOil pressure is low.Worn crankshaft main bearing
Worn connecting rod bearing (big end)
Oil pressure is normal.Loose flywheel mounting bolts
Damaged engine mounting
High-pitched clank
(Spark knock)Sound is noticeable when
accelerating with an overload.Ignition timing advanced
Accumulation of carbon inside combustion chamber
Wrong spark plug
Improper gasoline
Clank when engine speed is
medium (1,000 to 2,000 rpm).Sound is reduced when fuel
injector connector of noisy
cylinder is disconnected.
(NOTE*)Worn crankshaft main bearing
Worn bearing at crankshaft end of connecting rod
Knocking sound when engine
is operating under idling speed
and engine is warm.Sound is reduced when fuel
injector connector of noisy
cylinder is disconnected.
(NOTE*)Worn cylinder liner and piston ring
Broken or stuck piston ring
Worn piston pin and hole at piston end of connecting rod
Sound is not reduced if each
fuel injector connector is
disconnected in turn. (NOTE*)Unusually worn valve lifter
Worn camshaft journal bore in crankcase
Squeaky sound—Insufficient generator lubrication
Rubbing sound—Defective generator brush and rotor contact
Gear scream when starting
engine—Defective ignition starter switch
Worn gear and starter pinion
Sound like polishing glass with
a dry cloth—Loose drive belt
Defective engine coolant pump shaft
Hissing sound—Loss of compression
Air leakage in air intake system, hoses, connections or
manifolds
Timing belt noise—Loose timing belt
Belt contacting case/adjacent part
Valve tappet noise—Incorrect valve clearance
NOTE*:
When disconnecting fuel injector connector, Malfunction Indicator Light (CHECK ENGINE light) illuminates and trouble code is stored in
ECM memory.
Therefore, carry out the CLEAR MEMORY MODE and INSPECTION MODE after connecting fuel injector connector. (Ref. to 2-7 On-Board
Diagnostics II System.)
80
2-3bDIAGNOSTICS
2. Engine Noise

1. Lubrication System
A: SPECIFICATIONS
1. 2200 cc MODEL
Lubrication methodForced lubrication
Oil pumpPump typeTrochoid type
Number of teethInner rotor 9
Outer rotor 10
Outer rotor diameter x thickness 78x9mm(3.07 x 0.35 in)
Tip clearance between inner and outer rotorSTANDARD 0.04 — 0.14 mm (0.0016 — 0.0055 in)
LIMIT 0.18 mm (0.0071 in)
Side clearance between inner rotor and pump
caseSTANDARD 0.02 — 0.07 mm (0.0008 — 0.0028 in)
LIMIT 0.15 mm (0.0059 in)
Case clearance between outer rotor and pump
caseSTANDARD 0.10 — 0.175 mm (0.0039 — 0.0069 in)
LIMIT 0.20 mm (0.0079 in)
Capacity at
80°C (176°F)700 rpm Discharge- pressure 98 kPa (1.0 kg/cm
2, 14 psi) or more
- quantity 4.2
(4.4 US qt, 3.7 Imp qt)/min.
5,000 rpm Discharge- pressure 294 kPa (3.0 kg/cm
2, 43 psi) or more
- quantity 42.0
(11.10 US gal, 9.24 Imp gal)/min.
Relief valve operation pressure 490 kPa (5.0 kg/cm
2, 71 psi)
Oil filterTypeFull-flow filter type
Filtration area 1,000 cm
2(155 sq in)
By-pass valve opening pressure 157 kPa (1.6 kg/cm
2, 23 psi)
Outer diameter x width 80 x 70 mm (3.15 x 2.76 in)
Oil filter to engine thread size M 20 x 1.5
Relief valve (on rocker shaft) operation pressure 69 kPa (0.7kg/cm
2, 10 psi)
Oil pressure
switchTypeImmersed contact point type
Working voltage — wattage 12 V — 3.4 W or less
Warning light activation pressure 14.7 kPa (0.15 kg/cm
2, 2.1 psi)
Proof pressure More than 981 kPa (10 kg/cm
2, 142 psi)
Oil pan capacity4.0
(4.2 US qt, 3.5 Imp qt)
2
2-4SPECIFICATIONS AND SERVICE DATA
1. Lubrication System

2. 2500 cc MODEL
Lubrication methodForced lubrication
Oil pumpPump typeTrochoid type
Number of teethInner rotor 9
Outer rotor 10
Outer rotor diameter x thickness 78 x 10 mm (3.07 x 0.39 in)
Tip clearance between inner and outer rotorSTANDARD 0.04—0.14 mm (0.0016—0.0055 in)
LIMIT 0.18 mm (0.0071 in)
Side clearance between inner rotor and pump
caseSTANDARD 0.02—0.07 mm (0.0008—0.0028 in)
LIMIT 0.15 mm (0.0059 in)
Case clearance between outer rotor and pump
caseSTANDARD 0.10—0.175 mm (0.0039—0.0069 in)
LIMIT 0.20 mm (0.0079 in)
Capacity at
80°C (176°F)600 rpm Discharge- pressure 98 kPa (1.0 kg/cm
2, 14 psi) or more
- quantity 4.6
(4.9 US qt, 4.0 Imp qt)/min.
5,000 rpm Discharge- pressure 294 kPa (3.0 kg/cm
2, 43 psi) or more
- quantity 47.0
(12.4 US gal, 10.3 Imp gal)/min.
Relief valve operation pressure 588 kPa (6.0 kg/cm
2, 85 psi)
Oil filterTypeFull-flow filter type
Filtration area 1,000 cm
2(155 sq in)
By-pass valve opening pressure 157 kPa (1.6 kg/cm
2, 23 psi)
Outer diameter x width 80 x 70 mm (3.15 x 2.76 in)
Oil filter to engine thread size M 20 x 1.5
Oil pressure
switchTypeImmersed contact point type
Working voltage—wattage 12 V—3.4 W or less
Warning light activation pressure 14.7 kPa (0.15 kg/cm
2, 2.1 psi)
Proof pressure More than 981 kPa (10 kg/cm
2, 142 psi)
Oil pan capacity4.5
(4.8 US qt, 4.0 Imp qt)
3
2-4SPECIFICATIONS AND SERVICE DATA
1. Lubrication System

B2M0315B
2) Install inner and outer rotors in their original positions.
3) Install oil relief valve and relief spring.
4) Install oil pump cover.
Tightening torque:
T1: 5
+1
0N⋅m (0.5+0.1
0kg-m, 3.6+0.7
0ft-lb)
T2: 44.1±3.4 N⋅m (4.5±0.35 kg-m, 32.5±2.5 ft-lb)
B2M0319A
E: INSTALLATION
Installation is in the reverse order of removal.
Do the following:
1) Apply fluid packing to matching surfaces of oil pump.
Fluid packing:
THREE BOND 1215 or equivalent
2) Replace O-ring with a new one.
3) Be careful not to scratch oil seal when installing oil
pump on cylinder block.
CAUTION:
Apply fluid packing to oil pressure switch threads
before installation.
Fluid packing:
THREE BOND 1215 or equivalent
8
2-4SERVICE PROCEDURE
1. Oil Pump

Lower level
3.5
(3.7 US qt, 3.1 Imp qt)
G2M0088
3. Oil Pressure Switch
A: REMOVAL
1) Remove alternator from bracket.
(1) Disconnect connector and terminal from generator.
B2M0017
(2) Remove V-belt cover.
(3) Loosen lock bolt and slider bolt, and remove front
side V-belt.
G2M0090
(4) Remove bolts which install generator on bracket.
G2M0091
2) Disconnect terminal from oil pressure switch.
3) Remove oil pressure switch.
15
2-4SERVICE PROCEDURE
2. Oil Pan and Oil Strainer