Kavlico Corp. has developed an oil quality sensor that measures changes in the dielectric constant of oil, which gradually increases as antioxidant additives in the oil deplete and rapidly increases if coolant contaminates the oil. Sensor output increases as the dielectric constant increases. The sensor requires 5V input and the output changes from 0.5 to 4.5 volts through the lifespan of the engine oil. Operating temperature is -40° to + 125°C.