History: In the past, all marked and unmarked police vehicles would come in monthly for an oil change, lube and safety check. As a test, we switched two marked Chevrolet Caprice vehicles over to 100% synthetic AMSOIL engine oil and extended the drain intervals to 20,000 miles, with a new oil filter installed at 10,000 miles. The vehicles were still scheduled to come in monthly for a safety inspection (tires, brakes, suspension, lights, etc..), but the oil is not drained, only a sample is taken. When the two test vehicles reached 70,000 miles, the municipality technicians removed the oil pans and also removed the main and rod bearings to check for wear using the plastic gauge test. The bearings showed very little wear. the same procedure was performed on two marked cars, same year, make and model, using petroleum oil. The wear on the two vehicles with petroleum oil, changed monthly at about 2,500-3,000 miles, showed slightly more wear in the plastic gauge test. The results were well within specifications in both cases.

Currently the city is using all Ford Crown Victoria's in its police fleet. With the help of oil analysis, we were able to extend our oil changes to 18,000-20,000 miles with a new filter installed at 9,000-10,000 miles. We are currently using AMSOIL synthetic engine, transmission, and rear differential oil in all vehicles serviced out of the city hall facility.

SAVINGS: Savings have been noticed due to the decrease in number of oil filters and quarts of oil purchased and disposed of. Labor time to complete a preventative maintenance (A or B) on a vehicle has been reduced, allowing up to 50% more vehicles to be serviced each day. To date, we have not had to re-build an engine or transmission with the new extended oil change intervals.