Properly managing coolants can help fleets to avoid costly problems. It’s easy for the radiator to be topped off with the wrong fluid, so proper maintenance procedures are essential so that the driver or technician knows which vehicle receives which coolant type.
One of the biggest problems is the misconception that all coolants are the same and interchangeable. That is incorrect and engine damage can occur if the wrong coolants are mixed. There are two very different types of coolants: conventional fully formulated and extended life (or organic acid technology or OAT). They protect engines from corrosion very differently and if you mix the two, both will be diluted, and neither will be effective. This could result in catastrophic corrosion which creates a hole from the coolant side of the cylinder liner through to the oil side. Oil analysis will show coolant in the oil, but the damage has already happened.
The solution is training. Anyone who may add coolant to a radiator needs to understand the type of coolant required by the vehicle and the danger of topping off with the wrong coolant. Drivers on the road can take a gallon or two of the required coolant with them and top off the system if necessary. This will require training and monitoring.
The best way to monitor coolants is with simple test strips. The paper test strips can be dipped into the coolant reservoir or radiator. If they turn one color, you’re all set and ready to go. A different color means that the coolant doesn’t have a high enough amount of additives to protect against corrosion. Check the freeze point of the coolant with a hygrometer, or for more accurate results, use a refractometer. This will tell you if the coolant has been diluted with water which will reduce its anti-corrosion properties.
If there are problems with the coolant and it’s out of spec, it can be corrected in many cases which will save draining and refilling the entire system. Concentrated coolants can be added, which will bring the coolant to recommended freeze points. A freeze point correction chart will show how the coolant should be adjusted to the proper level. Correction fluids are designed to restore additives to recommended levels. Doing these two things will bring the coolant back to the correct specification without draining the cooling system.