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
CYLINDER 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,
ADJACENT
CYLINDERS,
OR AIR
BUBBLES IN
COOLANT
1. Sealing
Surfaces
Repair Sealing
Surfaces
2. Gaskets 2. Replace
Component or
Gasket
3. Cylinder
Head Gasket
3. Replace
Cylinder Head
Gasket
AIR LOSS
THROUGH AIR
INTAKE AREA
1. Sealing
Surfaces
1. Remove
Cylinder Head
for Further
Inspection
2. Intake Valves
and Seats
2. Replace
Valves, Guides
or Seats
CONDITION POSSIBLE
CAUSES
CORRECTION
AIR LOSS
THROUGH
EXHAUST
Sealing
Surfaces
Remove
Cylinder Head
for Further
Inspection
2. Exhaust
Valves and
Seats
2. Replace
Valves, Guides
or Seats
AIR LOSS
THROUGH OIL
FILL OPENING
1. Sealing
Surfaces
Remove Engine
for Further
Inspection
2. Pistons,
Piston Rings
2. Replace
Pistons 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).
REMOVAL
WARNING: RISK OF INJURY TO SKIN AND EYES
FROM SCALDING WITH HOT COOLANT. RISK OF
POISONING FROM SWALLOWING COOLANT. DO
NOT OPEN COOLING SYSTEM UNLESS COOLANT
TEMPERATURE IS BELOW 90°C (194°F). OPEN CAP
SLOWLY TO RELEASE PRESSURE. STORE COOL-
ANT IN SUITABLE AND APPROPRIATELY MARKED
CONTAINER. WEAR PROTECTIVE GLOVES,
CLOTHES, AND EYE WEAR.
CAUTION: STORE OR DISCARD ALL FLUIDS IN
SUITABLE AND APPROPRIATELY MARKED CON-
TAINERS.
(1) Disconnect the negative battery cable.
9 - 4 ENGINE VA
ENGINE (Continued)
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