Symtech VFX 1 - Manual (Page 9)

8
DRAIN and FILL
(RED) versus REVERSE FLUSH (BLUE)
The VFX 1 Coolant exchange system offers two methods to easily perform coolant exchanges: DRAIN AND FILL
(RED) and REVERSE FLUSH (BLUE) . The following information describes the basic differences between the two
types, and the advantages and disadvantages of each.
DRAIN AND FILL
(RED) - entails using shop air pressure to create vacuum in the VFX 1. This vacuum is then used
to pull used coolant from the vehicle’s cooling system via the radiator cap or Remote Reservoir tank opening.
The resultant vacuum created in the vehicle’s cooling jacket is in turn used to pull in new coolant.
ADVANTAGES of the DRAIN AND FILL (RED) exchange are; speed, simplicity, and ease of use as the
cooling system is easily accessed. Shop mess is minimized as the coolant system remains intact and
air pockets are eliminated from the cooling system by the vacuum level reached during extraction.
DRAIN AND FILL does not involve adapters or in-depth knowledge of cooling systems.
DISADVANTAGES of a DRAIN AND FILL (RED) coolant exchange is less efficient on some vehicles.
Some coolant system configurations do not allow a large percentage of used coolant to be evacuated
via vacuum and the exchange process may produce inferior results. Many times the DRAIN AND
FILL
procedure can be repeated to obtain acceptable results, but this may be inefficient and more
costly than reverse flushing.
REVERSE FLUSH
(BLUE) – utilizes pressurized new coolant entering the vehicle’s cooling system, usually through
the upper radiator connection, flushing backwards through the engine block, and up through the radiator forcing
the used coolant out into the unit’s used coolant tank. Some systems have reverse flow cooling systems and the
new coolant may flush through the radiator first, then the engine block and out.
ADVANTAGES; The REVERSE FLUSH (BLUE) coolant exchange process is the most efficient and
effective method as the backwards flow of new coolant purges the old coolant and most debris out of
the system. Less new coolant is used to achieve excellent results.
DISADVANTAGES; A REVERSE FLUSH (BLUE) exchange requires breaking into the cooling system
via adapters and hoses. This sometimes requires more time to perform exchange, creates air pockets
that will need to be “burped” from the vehicle, and there is more potential for spillage of coolant than a
DRAIN AND FILL service. The REVERSE FLUSH exchange also requires a more in depth
understanding of cooling system flow and operation.
Both types of exchanges are easily performed by simply following the colored control panel valve sequence.