Coolant field testing

Field testing is the principle of testing a coolant in a real life environment, a specified amount of vehicles is filled up with the coolant to be tested, the vehicles will drive for a predetermined mileage. During this period, in between samples are taken at specified intervals. Samples are analysed in the lab, based on the results we can obtain trends on pH, concentration, inhibitor content and possible contaminants. This gives an indication on what to expect at the end of the field test. When the specified mileage is obtained, the vehicles are inspected.

All parts that have been in contact with coolant are inspected, based on visual appearance and a second more detailed inspection in the lab:

• Radiator and heater core: channels are inspected for corrosion, possible blockages, leakages or deposits. In case of deposits, the deposits are analyzed to find the root cause.

• Water pump: inspected for corrosion, leakages and possible damage to the propeller (cavitation) or the seals.

• Hoses and Elastomers: inspected for damage or deposits.

• Cylinder head: analysis of the coolant channels for corrosion or possible deposits.

• Cylinder liners (for heavy duty): inspected for corrosion or cavitation.

Other parts might be inspected based on the engine system. Some field tests can take years based on the predefined mileage especially for heavy duty where engines typically have more mileage during their life span.

Before the start-up of a fleet test, the coolant has passed all the required lab and bench test results imposed by the OEM (ASTM, JIS, CEC, OEM specific, etc.). These are all lab tests that are carried out in a controlled environment. Reason for this is that a lab test need repeatability and differentiation, which is harder to obtain in a real life situation like a field test. There are lots of variables that can affect the performance of the coolant: engine coolant circuit (flow pattern), engine temperature, materials of components, start/stop ratio but also less considered variables like driving style, outside temperature, humidity, road conditions, etc. .This is both the strength and limitation of field tests. Lab tests are most of the time essentially a controlled simulation of an issue that has been seen in the field, this implies the importance of field data for new development. Knowing the issues you might run into is one step closer to overcoming them.

Field testing is the last validation step in the development of a coolant to obtain final approval. In case results are not meeting expectations, this can lead to a reformulation based on lab tests simulating the observed issues. This means the coolant will need approval again for the standard tests imposed by the OEM.