GxT Ferret 21 Smoke - Manual (Page 9)

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Engine Mechanical - Head Gasket (Cooling System)
A head gasket, or similar failure, may be diagnosed by fi lling either the crankcase or the cooling system
with smoke.
FOG WILL NOT ALWAYS DISPLACE LIQUID. TO CHECK FOR ANY LIQUID LEAK, THE AREA SHOULD
BE DRAINED.
If you suspect that you are losing coolant from the cooling system into a combustion chamber, drain the
cooling system lower than the head gaskets. Remove the spark plugs from the suspect cylinders. Use
the appropriate adapter to seal the radiator fi ller neck. Allow about 2 minutes of operation then carefully
observe the intake area, the spark plug holes and the tailpipe area. If fog is observed at either exhaust
or intake, a cracked head or valve seat may be indicated. Fog from a spark plug hole indicates a head
gasket leak.
Engine Mechanical - Head Gasket (Between Cylinders)
Removing the spark plugs, will reveal the fog path from one side of the leak, to the other. Bring one of
the suspected cylinders up to TDC on compression and apply CoolSmoke to that cylinder. If the gasket
(or cylinder head) leak is between cylinders, fog will appear at the cylinder, or at the intake or exhaust,
depending on the current position of the valve train.
REPEAT THE PROCEDURE FOR THE OTHER CYLINDER FOR CONFIRMATION.
Engine Mechanical - Head Gasket (Coolant to Oil)
If coolant is found in the engine oil, there are a number of potential paths that could leak to cause this
condition. While impossible to be defi nitive about the exact path, it is usually possible to confi rm that
the condition exists.
Applying CoolSmoke to the radiator (after draining the coolant) will eventually cause fog to appear at either
the oil fi ller location, the dipstick tube or the pcv valve. If all 3 components are left in the open position,
observing where the fog fi rst appears may provide clues to the path of the leak.
Engine Mechanical - Cylinder Condition
Remove all of the spark plugs, remove the air cleaner from the carb/throttle body, pull the dipstick tube
and the oil fi ller cap to proceed. Perform a dry compression test and record the readings.
Starting with the lowest reading cylinder, bring each cylinder to TDC on compression before you apply the
CoolSmoke. Apply for about 1 minute to each cylinder in turn. Ideally, there should be no fog anywhere
except inside the cylinder you are working on. Fog at the throttle area indicates intake valve leakage.
Fog at the exhaust would indicate exhaust valve leakage and fog at the oil fi ller or dipstick tube would
indicate piston ring leakage.