Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Service manual — part 18

PM-10

V-belt

PERIODIC MAINTENANCE SERVICES

6. V-belt

A: INSPECTION

CAUTION:

Check and adjust the front side belt tension so

that it is within the specified range. Using the

belt with a tension out of the specified range

may result in a fault such as the following:

• If the front side belt tension is higher, unex-

pected force is generated at the power steering

oil pump, generator and crankshaft bearing,

causing abnormal noise due to abnormal wear

of the bearing.

• If the front side belt tension is lower, the front

side belt and crank pulley slip, causing abnor-

mally high temperature on the crank pulley due

to frictional heat. If this condition repeatedly

occurs, the front side belt may abnormally

wear, causing abnormal noise, front side belt

damage or crank pulley damage.
NOTE:

Since the rear belt is a stretch type belt, it does not

require tension check and adjustment.

1. PROCEDURE (WITHOUT BELT TEN-

SION GAUGE)

1) Replace the belts if cracks, fraying or wear are

found.

2) Check the V-belt tension and adjust it if neces-

sary by changing the generator installing position

or idler pulley installing position. <Ref. to PM-10,

REPLACEMENT, V-belt.>
When pressing with belt tension 98 N (10 kgf, 22

lbf)

When replacing: 7 — 9 mm (0.276 — 0.354 in)

When reusing: 9 — 11 mm (0.354 — 0.433 in)

2. PROCEDURE (WITH BELT TENSION

GAUGE)

1) Replace the belts if cracks, fraying or wear are

found.

2) Remove the V-belt covers and radiator reservoir

tank.

3) Check the belt tension, using the belt tension

gauge. Adjust the tension, if necessary by chang-

ing the generator installing position or idler pulley

installing position.
Belt tension

When installing new parts:

640 — 780 N (65 — 80 kgf, 144 — 175 lbf)

At inspection:

490 — 640 N (50 — 65 kgf, 110 — 144 lbf)

B: REPLACEMENT

1. FRONT SIDE BELT (FOR POWER

STEERING OIL PUMP AND GENERATOR)

NOTE:

Wipe off any oil or water on the belt and pulley.

1) Remove the V-belt covers.

2) Loosen the lock bolt (A).

3) Loosen the slider bolt (B).

4) Remove the front side belt (C).

(A) Front side belt
(B) Rear side belt

(C) 98 N (10 kgf, 22 lbf)

C/P Crank pulley

GEN Generator pulley

P/S Power steering oil pump pulley

A/C A/C compressor pulley

ME-03314

(A)

(B)

GEN

C/P

A/C

P/S

(C)

(A) Front side belt
(B) Rear side belt

C/P Crank pulley

GEN Generator pulley

P/S Power steering oil pump pulley

A/C A/C compressor pulley

ME-03313

C/P

P/S

A/C

GEN

(A)

(B)

PM-00378

PM-11

V-belt

PERIODIC MAINTENANCE SERVICES

5) Install a new belt, and tighten the slider bolt so as

to obtain the specified belt tension.

6) Tighten the lock bolt (A).

7) Tighten the slider bolt (B).
Tightening torque:

Lock bolt

25 N·m (2.5 kgf-m, 18.4 ft-lb)

Slider bolt

8 N·m (0.8 kgf-m, 5.9 ft-lb)

8) Start and run the engine for approximately five

minutes to allow the V-belt to become fitted. (When

using the gauge)

9) Stop the engine, check the belt tension and ad-

just as necessary. (When using the gauge)

10) Start and run the engine for approximately one

minute to allow the V-belt to become fitted. (When

using the gauge)

11) Stop the engine and check that the belt tension

is within the specification. (When using the gauge)

12) Adjust until the specified belt tension is ob-

tained. (When using the gauge)

2. REAR SIDE BELT (FOR A/C)

CAUTION:

Always use new rear side belt.

1) Remove the front side belts.

2) Cut the rear side belt.

3) Install a new belt using an installation jig. <Ref.

to ME(STI)-41, REAR SIDE BELT, INSTALLA-

TION, V-belt.> <Ref. to ME(w/o STI)-39, REAR

SIDE BELT, INSTALLATION, V-belt.>

4) Install the front side belt. <Ref. to ME(STI)-40,

INSTALLATION, V-belt.> <Ref. to ME(w/o STI)-38,

INSTALLATION, V-belt.>

PM-00379

(B)

(A)

(C)

PM-12

Timing Belt

PERIODIC MAINTENANCE SERVICES

7. Timing Belt

A: INSPECTION

1. CHECK TIMING BELT POSITION

1) Remove the timing belt cover (LH) and (RH).

2) Turn the crank pulley and align single line mark

(A) on the intake cam sprocket (RH) with notch (B)

on timing belt cover and check the following.

(1) Make sure double lines (C) on intake and

exhaust cam sprocket (RH side) are aligned.

(2) Make sure single line (D) on exhaust cam

sprocket (RH side) is aligned to timing belt cov-

er notch (E).

(3) Make sure single line (A) on intake cam

sprocket (LH side) is aligned to timing belt cover

notch (B).

(4) Make sure double lines (C) on intake and

exhaust cam sprocket (LH side) are aligned.

(5) Check that the single line mark (D) on the

exhaust cam sprocket (LH side) and notch (E)

on the timing belt cover are aligned.

3) When cam sprocket position is offset, check for

any defect, and repair or replace as required.

2. OTHER INSPECTIONS

1) Remove the timing belt cover (LH).

2) While cranking engine at least four rotations,

check the timing belt back surface for cracks or

damage. Replace faulty timing belts with new parts

as required.

3) When the side part of timing belt (arrow direction

shown in the figure) is abnormally worn (fluff or

jumping out of core) or damaged, check the idlers,

tensioner, water pump pulley and cam sprocket to

determine idler alignment (squareness). Replace

the worn timing belt with new part.

4) Install the timing belt cover (LH).

PM-00538

(D)

(E)

(C)

(A)

(B)

PM-00539

(D)

(E)

(C)

(A)

(B)

PM-00343

PM-13

Timing Belt

PERIODIC MAINTENANCE SERVICES

B: REPLACEMENT

1) Remove the radiator fan and air conditioner fan.

<Ref. to CO(STI)-23, Radiator Main Fan and Fan

Motor.> <Ref. to CO(STI)-25, Radiator Sub Fan

and Fan Motor.> <Ref. to CO(w/o STI)-23, Radiator

Main Fan and Fan Motor.> <Ref. to CO(w/o STI)-

25, Radiator Sub Fan and Fan Motor.>

2) Protect the radiator with cardboard and blanket.

3) Remove the V-belt covers.

4) Remove the V-belts. <Ref. to ME(STI)-40, V-

belt.> <Ref. to ME(w/o STI)-38, V-belt.>

5) Remove the crank pulley. <Ref. to ME(STI)-47,

REMOVAL, Crank Pulley.> <Ref. to ME(w/o STI)-

45, REMOVAL, Crank Pulley.>

6) Remove the timing belt cover. <Ref. to ME(STI)-

49, REMOVAL, Timing Belt Cover.> <Ref. to

ME(w/o STI)-47, REMOVAL, Timing Belt Cover.>

7) Using ST, turn the crankshaft and align the align-

ment marks on crankshaft and left and right cam

sprockets with alignment marks of belt cover and

oil pump.

ST 499987500

CRANKSHAFT SOCKET

8) Remove the belt idler.

9) Remove the timing belt.

10) Remove the automatic belt tension adjuster as-

sembly.

11) Install in the reverse order of removal. <Ref. to

ME(STI)-52, INSTALLATION, Timing Belt.> <Ref.

to ME(w/o STI)-50, INSTALLATION, Timing Belt.>
CAUTION:

When installing the timing belt, be sure to align

all alignment marks on the belt with corre-

sponding marks on the sprockets. If incorrectly

installed, interference between pistons and

valves may occur.

PM-00378

ME-00070

PM-00555

PM-00521

PM-00096