NOTE: If the retaining lock is installed, remove it,
rotate engine and install lock once again.
(2) Carry out test of other cylinders in the firing
order of engine.
CYLINDER LEAK DOWN VALUES
CYLINDER LEAK
DOWN PERMISSIBLE
TOTAL LOSS
± 25%
CYLINDER LEAK
DOWN PERMISSIBLE
LOSS AT VALVES AND
CYLINDER HEAD
± 10%
CYLINDER LEAK
DOWN PERMISSIBLE
LOSS AT PISTON AND
RINGS
± 20%
STANDARD PROCEDURE - DETERMINING CYL-
INDER PRESSURE LOSS
If an increased pressure loss was found with the
cylinder leak test, inspect the engine by listening at
the cylinder head gasket, air intake area, exhaust, oil
fill opening and where injectors and glow plugs enter
the cylinder head. Also check the engine coolant in
the radiator or expansion reservoir for the formation
of bubbles.
Possible causes for the pressure loss are:
POSSIBLE CAUSE FOR PRESSURE LOSS
CONDITION
POSSIBLE
CAUSES
CORRECTION
AIR LOSS
THROUGH
GLOW PLUG,
INJECTOR, AD-
JACENT CYL-
INDERS, OR
AIR BUBBLES
IN COOLANT
1. Sealing Sur-
faces
Repair Sealing
Surfaces
2. Gaskets
2. Replace
Component or
Gasket
3. Cylinder
Head Gasket
3. Replace Cyl-
inder Head
Gasket
AIR LOSS
THROUGH AIR
INTAKE AREA
1. Sealing Sur-
faces
1. Remove Cyl-
inder Head for
Further Inspec-
tion
CONDITION
POSSIBLE
CAUSES
CORRECTION
2. Intake
Valves and
Seats
2. Replace
Valves, Guides
or Seats
AIR LOSS
THROUGH EX-
HAUST
Sealing Surfac-
es
Remove Cylin-
der Head for
Further Inspec-
tion
2. Exhaust
Valves and
Seats
2. Replace
Valves, Guides
or Seats
AIR LOSS
THROUGH OIL
FILL OPENING
1. Sealing Sur-
faces
Remove Engine
for Further In-
spection
2. Pistons, Pis-
ton Rings
2. Replace Pis-
tons or Piston
Rings
It is possible to pin point the pressure loss of the
relevant cylinder by spraying with clean engine oil.
Engine oil seals off the gap between the piston and
cylinder wall briefly. If a reduced pressure loss now
occurs for a short time, the cause is very likely to be
the pistons, piston rings or cylinder contact surfaces
of the relevant cylinder.
Determining the cause can be falsified by the posi-
tion of the piston ring joints. If suspicion exists that
the loss of pressure is caused by the piston ring
joints being positioned directly one above the other,
fit the parts to the engine and repeat this test after
running the engine for a short time.
REMOVAL
REMOVAL - ENGINE COVER
(1) Remove the retaining screws and remove cover
(Fig. 2).
9 - 4
ENGINE
VA