Five elements determine the health of a cooling/antifreeze system and these elements are extremely dependent on each other. Understanding that relationship will make cooling system maintenance easy.
1. Maintaining Freeze/Boil-over Protection
Maintaining a freeze/boil-over protection level between -30° F to -40° F is very important because it is the basis for entire cooling system protection. Over or under concentrations have adverse affections on the system's "health", both freeze protection and boil-over protection.
Too little freeze protection allows the coolant to freeze resulting in cracked engine blocks, cylinder heads, oil coolers, radiators, surge tanks, and heater cores. Too much antifreeze can cause similar damages, because the ethylene glycol base fluid must mix with water to activate the freeze protection chemistry.
A 50/50 mixture of Extended Life Coolant concentrate and clean water enables the mixture to withstand high and low temperatures. Take a sample of the engine coolant from the pressurized side of the cooling system using a dropper, such as that supplied with the refractometer. As an alternative, some systems may require the sample to be pulled from a surge or overflow tank. Check for proper freeze point protection using the refractometer, following the manufacturer's instructions for proper use.
2. Maintaining Metals Corrosion Protection
Maintaining metal corrosion protection is easy, if you have correctly monitored freeze protection. Extended Life Coolant is specially formulated to provide the correct amounts of metal corrosion protection inhibitors in the form of organic acid compounds when a 50/50 mixture of ELC concentrate and water is maintained. This 50/50 mix normally meets all the system requirements for freeze protection, metal corrosion protection, and heat transfer.
3. Understanding Heat Transfer
Removing heat from the engine's metal components is the primary job of any engine coolant. Depending on the duty cycle and power demand, these requirements can vary throughout the operating conditions of the vehicle.
Engine coolant takes on more "work" than ever before due to increases in internal cylinder pressures, higher power output, reduced radiator frontal area, multipass systems of the A/C condenser and charge air cooler package, smaller engine compartments, higher operating temperatures and Cooled Exhaust Gas Recirculation (CEGR).
Heat generated within the engine by the combustion process is transferred through the metal components of the cylinder liners, engine block, cylinder head(s), oil coolers, etc. to the coolant. The coolant absorbs this heat as it is pumped through the engine. Thermostats regulate the engine's coolant temperature based on engine design and emission
Depending on coolant type, a process referred to as "plating" can occur when certain coolant additives stick or coat themselves to metals they come in contact with. This
"plating" can introduce an additional barrier to the heat transfer process because the compounds act as insulators rather than conductors. See details in the Conventional Coolants section of this procedure.
De-aeration lines allow any air pockets introduced to bleed off into a "open" vented area of the radiator upper tank. Allowing the air to bleed off eliminates "dead" areas of circulation, collection of tiny bubbles on metal surfaces, and pump cavitation.
Once the heated coolant enters the radiator, air movement across the radiator core removes much of the heat from the coolant allowing it to absorb more heat as it passes through the engine again.
Anything that interrupts this thermal exchange cycle will have negative affects on the system's health.
4. Using Proper Additives
Follow manufacturer instructions to check and add any required additives.
5. Proper Cooling System Pressure
Cooling system pressure is required to aid coolant performance. Coolant under pressure has a higher boiling point. The combination of ethylene glycol/water mixture and moderate system pressure can raise the boiling point. Example, a 50/50 mixture with a 15 psi pressure cap will raise the boiling point to 265.
Pressure on the system also reduces the level of aeration generated in the system. Aeration
can lead to other problems as it will rapidly deplete the corrosion inhibitors of any coolant.
The vehicles radiator cap should always be inspected and pressure tested during regular cooling system maintenance.