COOLANT
4012/16 Diesel, February 1997 2
1
ENGINE COOLING SYSTEM
The cooling system of an engine contains
many different materials e.g. cast iron,
aluminium, copper, solder, rubber (various
types). To prevent deterioration of these
materials, it is essential to use a very good
quality coolant. Untreated water is not
suitable. It is essential that the water is
treated with an additive that gives the
necessary protection.
WATER QUALITY
The water to be mixed with the additive must
have the following characteristics:
Chlorides less than 80 PPMV
(PPMV = parts per million by volume)
Sulphates less than 80 PPMV
Total hardness less than 200 PPMV
pH of water between 7 to 7.5
(neutral to slightly alkaline)
ADDITIVES TO WATER
Due to the complexity of the cooling system
it is necessary to use an additive that
contains a balanced package of corrosion
inhibitors.
To achieve the required solution a 50/50 mix
of Shell Safe Premium antifreeze with water
should be used at all times, even in areas
where frost is unlikely.**
The 50/50 mixture will give frost protection
down to -35°C. In areas where Shell Safe
Premium is not available contact Perkins
Engines (Stafford) Limited for advice on a
recommended alternative.
Under no circumstances should an additive
containing nitrites, borates, phosphates,
chromates, nitrates, or silicates be used, as
they are not compatible with the materials
used in the cooling system.
When mixing the antifreeze with the water
always follow the manufacturer's
recommendation to add the antifreeze in the
correct proportion before introducing it into
the engine cooling system. Adding water to
antifreeze can lead to the formation of a gel
in the mixture, which can cause blockage of
the water passages and subsequent local
overheating.
MAINTENANCE OF COOLANT
The water/antifreeze mixture should be
regularly replaced in operating engines at
least once a year.
In engines used for standby duty it is
essential to maintain the water/antifreeze
mixture at the correct alkalinity level i.e. the
pH should not increase above 7.5. A
hydrometer only shows the proportion of
ethylene glycol, not the degree of corrosion
protection.
4012TWG2 only to this rule is when two
section radiators are used in conjunction
with charge air coolers under tropical
conditions. It may be necessary to reduce
the antifreeze content of the coolant from
50% to 10% to achieve an adequate heat
transfer coefficient.
WARNING
ALWAYS STOP THE
ENGINE AND ALLOW
THE PRESSURISED SYSTEM TO COOL
BEFORE REMOVING FILLER CAP.
AVOID SKIN CONTACT WITH
ANTIFREEZE BY WEARING HAND, ETC.
WARNING
FAILURE TO FOLLOW
THE ABOVE
RECOMMENDATIONS MAY RESULT IN
DAMAGE TO THE ENGINE, AND WILL
INVALIDATE THE ENGINE WARRANTY.
