1999 SUBARU LEGACY low oil pressure

Diagnosis of engine condition by measurement of manifold vacuum
Vacuum gauge indication Possible engine condition
1. Needle is steady but lower than normal position. This ten-
dency becomes more evident as engine temperature rises.Leakage around intake manifold gasket or disconnection or
damaged vacuum hose
2. When engine speed is reduced slowly from higher speed,
needle stops temporarily when it is lowering or becomes
steady above normal position.Back pressure too high, or exhaust system clogged
3. Needle intermittently drops to position lower than normal
position.Leakage around cylinder
4. Needle drops suddenly and intermittently from normal posi-
tion.Sticky valves
5. When engine speed is gradually increased, needle begins
to vibrate rapidly at certain speed, and then vibration
increases as engine speed increases.Weak or broken valve springs
6. Needle vibrates above and below normal position in narrow
range.Defective ignition system or throttle chamber idle adjustment
6. Engine Oil Pressure
A: MEASUREMENT
1) Disconnect battery ground cable.
2) Remove generator from bracket.
(1) Disconnect connector and terminal from
generator.
G2M0088
(2) Remove V-belt cover
G2M0089
(3) Loosen lock bolt and slider bolt, and remove
V-belt for generator.
(4) Remove generator lock bolt.
(5) Remove bolt which install generator on
bracket.
G2M0090
3) Disconnect connector from oil pressure switch.
4) Remove oil pressure switch from engine cylin-
der block.
G2M0091
5) Connect oil pressure gauge hose to cylinder
block.
6) Connect battery ground cable.
7) Start the engine, and measure oil pressure.
6
2-2[W6A0]SERVICE PROCEDURE
6. Engine Oil Pressure

Diagnosis of engine condition by measurement of manifold vacuum
Vacuum gauge indication Possible engine condition
1. Needle is steady but lower than normal position. This ten-
dency becomes more evident as engine temperature rises.Leakage around intake manifold gasket or disconnection or
damaged vacuum hose
2. When engine speed is reduced slowly from higher speed,
needle stops temporarily when it is lowering or becomes
steady above normal position.Back pressure too high, or exhaust system clogged
3. Needle intermittently drops to position lower than normal
position.Leakage around cylinder
4. Needle drops suddenly and intermittently from normal posi-
tion.Sticky valves
5. When engine speed is gradually increased, needle begins
to vibrate rapidly at certain speed, and then vibration
increases as engine speed increases.Weak or broken valve springs
6. Needle vibrates above and below normal position in narrow
range.Defective ignition system or throttle chamber idle adjustment
6. Engine Oil Pressure
A: MEASUREMENT
1) Disconnect battery ground cable.
2) Remove generator from bracket.
(1) Disconnect connector and terminal from
generator.
G2M0088
(2) Remove V-belt cover
G2M0089
(3) Loosen lock bolt and slider bolt, and remove
V-belt for generator.
(4) Remove generator lock bolt.
(5) Remove bolt which install generator on
bracket.
G2M0090
3) Disconnect connector from oil pressure switch.
4) Remove oil pressure switch from engine cylin-
der block.
G2M0091
5) Connect oil pressure gauge hose to cylinder
block.
6) Connect battery ground cable.
7) Start the engine, and measure oil pressure.
6
2-2[W6A0]SERVICE PROCEDURE
6. Engine Oil Pressure

S2M0242
Oil pressure:
98 kPa (1.0 kg/cm2,14 psi) or more at 800
rpm
294 kPa (3.0 kg/cm
2, 43 psi) or more at
5,000 rpm
CAUTION:
IIf oil pressure is out of specification, check
oil pump, oil filter and lubrication line. 2-4 [K100].>
IIf oil pressure warning light is turned ON and
oil pressure is in specification, replace oil pres-
sure switch.
NOTE:
The specified data is based on an engine oil tem-
perature of 80ÉC (176ÉF).
8) After measuring oil pressure, install oil pressure
switch.
Tightening torque:
25
±3 N´m (2.5±0.3 kg-m, 18.1±2.2 ft-lb)
9) Install generator and V-belt in the reverse order
of removal, and adjust the V-belt deflection.
7. Valve Clearance
A: INSPECTION
1. 2200 cc MODEL
CAUTION:
Inspection and adjustment of valve clearance
should be performed while engine is cold.
1) Set the vehicle onto the lift.
2) Disconnect battery ground cable.
B2M1723
3) Remove engine coolant reservoir tank. 2-5 [W9A0].>
S2M0028
4) Remove timing belt cover (LH).
B2M2031
5) Remove rocker cover.
IWhen inspecting #1 and #3 cylinders:
ILow emission vehicle:
7
[W7A1]2-2SERVICE PROCEDURE
7. Valve Clearance

S2M0242
Oil pressure:
98 kPa (1.0 kg/cm2,14 psi) or more at 800
rpm
294 kPa (3.0 kg/cm
2, 43 psi) or more at
5,000 rpm
CAUTION:
IIf oil pressure is out of specification, check
oil pump, oil filter and lubrication line. 2-4 [K100].>
IIf oil pressure warning light is turned ON and
oil pressure is in specification, replace oil pres-
sure switch.
NOTE:
The specified data is based on an engine oil tem-
perature of 80ÉC (176ÉF).
8) After measuring oil pressure, install oil pressure
switch.
Tightening torque:
25
±3 N´m (2.5±0.3 kg-m, 18.1±2.2 ft-lb)
9) Install generator and V-belt in the reverse order
of removal, and adjust the V-belt deflection.
7. Valve Clearance
A: INSPECTION
1. 2200 cc MODEL
CAUTION:
Inspection and adjustment of valve clearance
should be performed while engine is cold.
1) Set the vehicle onto the lift.
2) Disconnect battery ground cable.
B2M1723
3) Remove engine coolant reservoir tank. 2-5 [W9A0].>
S2M0028
4) Remove timing belt cover (LH).
B2M2031
5) Remove rocker cover.
IWhen inspecting #1 and #3 cylinders:
ILow emission vehicle:
7
[W7A1]2-2SERVICE PROCEDURE
7. Valve Clearance

3) Remove crankshaft sprocket.
B2M2600A
S2M0414A
4) Remove belt cover No. 2 (LH).
5) Remove belt cover No. 2 (RH).
CAUTION:
Do not damage or lose the seal rubber when
removing belt covers.
B2M2601
6) Remove tensioner bracket.
H2M2380
B: INSPECTION
1. TIMING BELT
1) Check timing belt teeth for breaks, cracks, and
wear. If any fault is found, replace belt.
2) Check the condition of back side of belt; if any
crack is found, replace belt.
CAUTION:
IBe careful not to let oil, grease or coolant
contact the belt. Remove quickly and thor-
oughly if this happens.
IDo not bend the belt sharply.
Bending radius: h
60 mm (2.36 in) or more
G2M0115
2. AUTOMATIC BELT TENSION
ADJUSTER
1) Visually check oil seals for leaks, and rod ends
for abnormal wear or scratches. If necessary,
replace faulty parts.
CAUTION:
Slight traces of oil at rod's oil seal does not
indicate a problem.
2) Check that the adjuster rod does not move
when a pressure of 294 N (30 kg, 66 lb) is applied
to it. This is to check adjuster rod stiffness.
3) If the adjuster rod is not stiff and moves freely
when applying 294 N (30 kg, 66 lb), check it using
the following procedures:
(1) Slowly press the adjuster rod down to the
end surface of the cylinder. Repeat this motion
2 or 3 times.
(2) With the adjuster rod moved all the way up,
apply a pressure of 294 N (30 kg, 66 lb) to it.
Check adjuster rod stiffness.
(3) If the adjuster rod is not stiff and moves
down, replace the automatic belt tension
adjuster assembly with a new one.
CAUTION:
IAlways use a vertical type pressing tool to
move the adjuster rod down.
IDo not use a lateral type vise.
IPush adjuster rod vertically.
18
2-3a[W2B1]SERVICE PROCEDURE
2. Timing Belt

5. Cylinder Head
A: REMOVAL
1. RELATED PARTS
1) Release fuel pressure.
2) Drain engine coolant.
3) Remove V-belt(s).
4) Remove generator and bracket.
5) Remove A/C compressor and bracket. (With
A/C model)6) Disconnect spark plug cords.
7) Remove connector bracket attaching bolt.
8) Remove camshaft position sensor and cam-
shaft position sensor support.
9) Disconnect oil pressure switch connector.
10) Disconnect blow-by hose.
11) Remove intake manifold. [W4A0].>
2. CYLINDER HEAD
B2M2627A
(1) Rocker cover
(2) Cylinder head bolt(3) Cylinder head
(4) Cylinder head gasket
1) Remove timing belt, camshaft sprocket and
related parts.

2) Remove oil level gauge guide attaching bolt
(left hand only) and oil level gauge guide.
3) Remove rocker cover.
40
2-3a[W5A1]SERVICE PROCEDURE
5. Cylinder Head

2) Tighten cylinder head bolts.
(1) Apply a coat of engine oil to washers and
bolt threads.
(2) Tighten all bolts to 29 N´m (3.0 kg-m, 22
ft-lb) in alphabetical sequence.
Then tighten all bolts to 69 N´m (7.0 kg-m, 51
ft-lb) in alphabetical sequence.
(3) Back off all bolts by 180É first; back them off
by 180É again.
(4) Tighten bolts (a) and (b) to 34 N´m (3.5
kg-m, 25 ft-lb).
(5) Tighten bolts (c), (d), (e) and (f) to 15 N´m
(1.5 kg-m, 11 ft-lb).
(6) Tighten all bolts by 80 to 90É in alphabetical
sequence.
CAUTION:
Do not tighten bolts more than 90É.
(7) Further tighten all bolts by 80 to 90É in
alphabetical sequence.
CAUTION:
Ensure that the total ªre-tightening angleº [in
the former two steps], do not exceed 180É.
B2M2628B
3) Install oil level gauge guide and tighten attach-
ing bolt (left side only).
4) Install timing belt, camshaft sprocket and
related parts.

2. RELATED PARTS
CAUTION:
Be careful not to scratch the mating surface of
cylinder block and oil pump.
1) Install engine coolant pipe.
2) Install intake manifold.
3) Connect blow-by hose.
4) Connect oil pressure switch connector.
5) Install camshaft position sensor and camshaft
position sensor support.
6) Install connector bracket attaching bolt.
7) Connect spark plug cords.
8) Install generator and bracket.
9) Install A/C compressor and bracket. (With A/C
model)
10) Install V-belt(s).
11) Remove ENGINE STAND (ST).
50
2-3a[W5E2]SERVICE PROCEDURE
5. Cylinder Head

TROUBLE PROBLEM PARTS, ETC. POSSIBLE CAUSE RANK
4) Engine stalls after initial
combustion.Fuel injection system A
IIntake systemILoosened or cracked intake uct B
ILoosened or cracked PCV hose C
ILoosened or cracked vacuum hose C
IDefective intake manifold gasket B
IDefective throttle body gasket B
IDirty air cleaner element C
IFuel lineIClogged fuel line C
ILack of or insufficient fuel B
IBeltIDefective B
IDefective timing B
ICompressionIIncorrect valve clearance C
ILoosened spark plugs or defective gasket C
ILoosened cylinder head bolts or defective gasket C
IImproper valve seating C
IDefective valve stem C
IWorn or broken valve spring B
IWorn or stuck piston rings, cylinder and piston C
IIncorrect valve timing B
IImproper engine oil (low viscosity) B
2. Rough idle and engine stall Fuel injection system A
IIntake systemILoosened or cracked intake duct A
ILoosened or cracked PCV hose A
ILoosened or cracked vacuum hose A
IDefective intake manifold gasket B
IDefective throttle body gasket B
IDefective PCV valve C
ILoosened oil filter cap B
IDirty air cleaner element C
IFuel lineIDefective fuel pump and relay C
IClogged fuel line C
ILack of or insufficient fuel B
IBeltIDefective timing C
ICompressionIIncorrect valve clearance B
ILoosened spark plugs or defective gasket B
ILoosened cylinder head bolts or defective gasket B
IImproper valve seating B
IDefective valve stem C
IWorn or broken valve spring B
IWorn or stuck piston rings, cylinder and piston B
IIncorrect valve timing A
IImproper engine oil (low viscosity) B
ILubrication systemIIncorrect oil pressure B
IDefective rocker cover gasket C
ICooling systemIOverheating C
IOthersIMalfunction of evaporative emission control system A
IStuck or damaged throttle valve B
IAccelerator cable out of adjustment C
74
2-3a[K100]DIAGNOSTICS
1. Engine Trouble in General