Subaru Legacy IV (2008 year). Manual - part 57

ME(H4SO)-24

Intake Manifold Vacuum

MECHANICAL

5. Intake Manifold Vacuum

A: INSPECTION

1) Warm up the engine.
2) Disconnect the brake booster vacuum hose from
the intake manifold, and then install the vacuum
gauge.
3) Keep the engine at idle speed and read the vac-
uum gauge indication.
By observing the gauge needle movement, the in-
ternal condition of the engine can be diagnosed as
described below.

Vacuum pressure (at idling, A/C “OFF”):

Less than –60.0 kPa 
(–450 mmHg, –17.72 inHg)

ME-02694

Diagnosis of engine condition by measurement of intake manifold vacuum

Vacuum gauge indication

Possible engine condition

1. Needle is steady but lower than normal position. This tendency 
becomes more evident as engine temperature rises.

Air leakage around intake manifold gasket, disconnection 
or damage of vacuum hose

2. Needle intermittently drops to position lower than normal position.

Leakage around cylinder

3. Needle drops suddenly and intermittently from normal position.

Sticky valve

4. 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

5. Needle vibrates above and below normal position in narrow range. Defective ignition system

ME(H4SO)-25

Engine Oil Pressure

MECHANICAL

6. Engine Oil Pressure

A: INSPECTION

1) Disconnect the ground cable from the battery.

2) Remove the oil pressure switch. <Ref. to
LU(H4SO)-20, REMOVAL, Oil Pressure Switch.>
3) Connect the oil pressure gauge to cylinder block.
4) Connect the ground cable to battery.

5) Start the engine, and measure the oil pressure.

Oil pressure:

Standard

98 kPa (1.0 kg/cm

2

, 14 psi) or more at 600 rpm

294 kPa (3.0 kg/cm

2

, 43 psi) or more at 5,000 

rpm

• If the oil pressure is out of specification, check oil
pump, oil filter and lubrication line. <Ref. to
LU(H4SO)-24, INSPECTION, Engine Lubrication
System Trouble in General.>
• If the oil pressure warning light is ON and oil
pressure is within specification, check the oil pres-
sure switch. <Ref. to LU(H4SO)-24, INSPECTION,
Engine Lubrication System Trouble in General.>

NOTE:
Standard value is based on an engine oil tempera-
ture of 80°C (176°F).
6) After measuring the oil pressure, install the oil
pressure switch. <Ref. to LU(H4SO)-20, INSTAL-
LATION, Oil Pressure Switch.>

IN-00203

IN-00203

ME-03698

ME(H4SO)-26

Fuel Pressure

MECHANICAL

7. Fuel Pressure

A: INSPECTION

CAUTION:
• Before removing the fuel pressure gauge, re-
lease the fuel pressure.
• Be careful not to spill fuel.
• Catch the fuel from hoses using a container
or cloth.

NOTE:
Check or replace the fuel pump and fuel delivery
line if the fuel pressure is out of the standard.
1) Release the fuel pressure. <Ref. to FU(H4SO)-
43, RELEASING OF FUEL PRESSURE, PROCE-
DURE, Fuel.>
2) Open the fuel filler lid, and remove the fuel filler
cap.
3) Disconnect the fuel delivery hose from the fuel
damper, and connect the fuel pressure gauge.

4) Start the engine.
5) Measure the fuel pressure after warming up the
engine.

NOTE:
The fuel pressure gauge registers 10 to 20 kPa (0.1
to 0.2 kg/cm

2

, 1 to 3 psi) higher than standard val-

ues during high-altitude operations.

Fuel pressure:

Standard:

338 — 348 kPa 
(3.4 — 3.5 kg/cm

2

, 49 — 50 psi)

ME-03054

ME(H4SO)-27

Valve Clearance

MECHANICAL

8. Valve Clearance

A: INSPECTION

NOTE:
Inspection and adjustment of valve clearance
should be performed while engine is cold.
1) Set the vehicle on a lift.
2) Lift up the vehicle.
3) Remove the under cover.
4) Lower the vehicle.
5) Disconnect the ground cable from the battery.

6) Remove the timing belt cover LH.

7) Remove the fuel injector. <Ref. to FU(H4SO)-
30, REMOVAL, Fuel Injector.>
8) When inspecting #1 and #3 cylinders

(1) Disconnect the spark plug cords from spark
plugs RH side. <Ref. to IG(H4SO)-4, RH SIDE,
REMOVAL, Spark Plug.>
(2) Place a suitable container under the vehicle.
(3) Disconnect the PCV hose from the rocker
cover RH.
(4) Remove the bolts, then remove the rocker
cover RH.

9) When inspecting #2 and #4 cylinders

(1) Disconnect the spark plug cords from spark
plugs on LH side. <Ref. to IG(H4SO)-4, LH
SIDE, REMOVAL, Spark Plug.>
(2) Place a suitable container under the vehicle.
(3) Disconnect the PCV hose from the rocker
cover LH.
(4) Remove the bolts, then remove the rocker
cover LH.

10) Set #1 cylinder piston to top dead center of
compression stroke by rotating the crank pulley
clockwise using the socket wrench.

NOTE:
When the arrow mark (A) on cam sprocket LH is at
the top position, the #1 cylinder piston is at top
dead center of the compression stroke.

11) Measure #1 cylinder valve clearance by using
thickness gauge (A).

NOTE:
• Insert the thickness gauge (A) in as horizontally
as possible with respect to the valve stem end face.
• Lift up the vehicle, and then measure the ex-
haust valve clearances.

Valve clearance:

Intake

0.20

r

0.04 mm (0.0079

r

0.0016 in)

Exhaust

0.25

r

0.04 mm (0.0098

r

0.0016 in)

12) If necessary, adjust the valve clearance. <Ref.
to ME(H4SO)-28, ADJUSTMENT, Valve Clear-
ance.>

IN-00203

ME-00199

ME-00200

( A )

ME-02696

(A)