MAHLE RTI ELF-1 - Manual (Page 11)

Page 8
Never assume that there is only one leak at a time.
The above procedure does not take into consideration vacuum lines or
devices controlled by a solenoid or a temperature or vacuum valve. They
should be treated individually.
Fog will not always displace liquid. The area should be drained to
check for any liquid leak.
VACUUM LINES - INTAKE MANIFOLD - PLENUM
Today’s vehicles are true engineering marvels. The sealing on and in the various systems has improved
tremendously over the last 10 to 15 years. Systems that leaked on a regular basis no longer leak at all,
and occasional leaks have become harder to find. Oil leaks are now almost as rare as fuel leaks and
can be much harder to pinpoint.
On-board computer systems may be instrumental in masking a drive ability problem. Frequently these
are repaired or components are replaced (such as a catalytic converter) that have failed with no
apparent reason.
The previous section discussed false air. Likewise, an intake leak can cause components to fail, drive
ability problems and difficult-to-diagnose emissions problems, especially idle related problems.
The most ideal manner to check an intake manifold is to go in through the fuel pressure regulator
vacuum hose, if it’s available. The PCV hose or main power brake booster hose are okay too. Remove
the hose at the regulator and use the large clear hose to adapt. Fill the manifold with fog. After about
30 seconds, any fog observed in the engine compartment must be investigated. Pay particular attention
under the plenum if possible. A frequency type leak detector will often pick out potential leaks in this
area, but can not usually pinpoint them.
Of course, a suspected leak at a vacuum line or any vacuum controlled device can be easily spotted
once it is filled with fog.
ENGINE MECHANICAL - HEAD GASKET - COOLING SYSTEM
A head gasket, or similar failure, may be diagnosed by filling either the crankcase or the cooling system
with fog. There are a number of ways to approach this diagnosis.
If it’s suspected that coolant is being lost from the cooling system into a combustion chamber, try the
following.
Drain the cooling system lower than the head gaskets. Remove the suspect spark plugs. Use the
appropriate adapter to seal the radiator filler neck with ELF-1 in the radiator. Allow about two 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 ELF-1 to that cylinder. Fog will appear
at the cylinder if the gasket or cylinder head leak is between cylinders or at the intake or exhaust,
depending on the current position of the valve train. Repeat the procedure for the other cylinder for an
absolute diagnosis.