|
FleetWatch Cooling Tips
& Tricks
Antifreeze/Anticorrosion inhibitor
- 100% antifreeze is no more effective
than a 30% mixture. Never install 100% antifreeze for top-up
coolant as it could damage the engine.
- Maintain coolant additives at the
level recommended by the original equipment manufacturer. For
the 120 000 ADE engines on the road, this is a ratio of 50:50
antifreeze to water. Some other OEM engines only recommend 30%
but remember that too much additive can harm the engine.
- Never exceed a 60:40 antifreeze/water
ratio as this will increase the risk of forming cooling system
gel which results as silicates drop-out of solution. This may
also not increase the protection characteristics of the coolant
additive and could decrease it.
- Never apply additional rust inhibitors,
radiator sealant or water pump lubricants containing soluble oil
to cooling systems. These may conflict with the approved coolant
additive and eliminate the effect of the anticorrosion chemicals.
- Where the engine is fitted with
a water filter, avoid antifreeze solutions that contain antileak
additives. These will rapidly restrict the filter and stop its
function.
Measuring the Antifreeze ratio
- This can be done accurately by means
of an instrument such as the Gefo-Glycomat Antifreeze Tester.
- Train staff in the use of the equipment.
Measuring coolant mixtures is not a hit-or-miss business based
on colour or rough estimates.
Changing Antifreeze and topping
up
- Engines should only be checked when
they are cold. Frequent topping up when there are no signs of
coolant leaks on a cold engine indicates a problem. Check for
leaks with the engine running at normal operating temperature.
Frequent topping up often goes unreported until a severe cooling
system failure occurs.
- Do not fill the radiator but do
fill the surge tank - the expansion bottle - to the level indicated
on the tank.
- Only top up with premixed coolant
to the correct ratio and specification. This seldom takes place
and results in dilution of the additives, rendering them ineffectual.
Do not use untested borehole water or water from an impure source
for premixing the coolant additive.
- Issue a written coolant additive
specification and choose a branded product that matches the specification.
Do not mix additives - this may cause a chemical reaction to
occur which could damage the cooling system.
- Flush and change the complete engine
coolant solution every two years at the maximum. Some truck OEMs
specify this as an annual procedure.
Monitor Cooling System Pressures
- Visually inspect radiator and surge
tank (expansion recovery bottle) caps for worn seals, cracked
springs and rusted valves.
- Conduct regular radiator pressure
tests with a pressure pump tester. Does the system maintain the
specified relief pressure and maintained pressure by holding the
correct pressure level?
General Items
- Radiator fins should be kept clean
of insect and road debris to ensure a good airflow. This is even
more critical with modern turbocharged/intercooled engines where
the intercooler radiator is in front of the engine radiator and
air has to flow through two radiators.
- Write up training procedures for
maintenance staff and drivers on cooling systems. Be very specific
on defect reports, topping up and the additive brand to be used.
- Train drivers to report engines
that are over-cooling as this is just as detrimental to engine
wear as engines that run too hot.
- Engines that are stripped for repair
must include a technical report on the condition of the cylinder
liners facing the coolant side. Verify that cooling system maintenance
procedures and their specified additives are matching the expected
levels of protection against corrosion and cavitation.
- Write a fleet purchasing specification
that matches the requirements of the truck engine manufacturer
for coolant additives. Cheapest will not be the answer.
Alternative Articles
Back
to top
|
