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Hendon Publishing

Oil Change or Not

The days of changing the oil every 3,000 miles are over. The 3,000-mile oil change figure dates back to 1968. Back then, it was both a conservative number and based on engine designs and oil technology at the time. Both have changed radically in the past 35 years.

GM’s algorithm-based Oil Life System (OLS) is pushing the police Impala and police Tahoe oil change interval beyond 5,000 patrol miles, and up to 10,000 miles in admin use. The OLS, which dates back to 1988, is based primarily on the engine’s rpm and the oil temperature history. As such, it gets around the number one maintenance exception for police: idle time.

General Motors has made it official. On its 2004 and newer police vehicles, do not change the oil every 3,000 miles. According to the Owner’s Manual, wait for the “Change Engine Oil” light in the message center of the dash. That means buying less oil, buying fewer filters, disposing of less oil, less shop labor to change oil and less vehicle downtime. And all this comes without risking the reliability or longevity of the engine and in full compliance with the factory warranty.

In 2007, Ford upped its oil change interval for police and special service vehicles from 3,000 miles to 5,000 miles. That same year, the company increased the oil change interval for its retail cars from 5,000 miles to 7,500 miles. Patrol vehicles driven like police cars should have the oil changed every 5,000 miles, but admin vehicles driven like retail cars can reasonably have the oil changed every 7,500 miles. If in doubt, do an oil analysis.

As for Dodge, the Charger Owner’s Manual states that under no circumstances should you exceed six months or 6,000 miles, whichever occurs first. The patrol Chargers will easily reach 6,000 miles first, however, the admin and detective Chargers may actually reach six months first. It also states that the oil should be changed more frequently if you drive off road, but that probably doesn’t mean center median crossing.

The much longer change intervals make three aspects of fleet maintenance more important than ever. First, use the right oil. This simply cannot be whatever your street department buys in bulk. You are now pushing the oil harder than ever in an already severe-duty application. It has to be the right oil, the right weight, the right API rating.

For those fleets running a mix of Ford CVPIs, Impalas and Chargers, remember that these three different police cars may take FOUR different weights of oil. The CVPIs older than 2001 use 5W-30, but most of these are out of service. That means virtually all CVPIs require 5W-20 oil. The Charger’s 5.7L HEMI® also uses 5W-20, however, the Charger’s 3.5L V-6 calls for 10W-30.

The right weight of oil for the Impala actually varies by the season! The correct oil for most climates and seasons is 5W-30, a different oil from the current CVPI and HEMI Charger, but the same as the pre-2001 CVPI. During frigidly cold seasons, the Impala calls for 0W-30.

You run a different weight of oil at your own risk. You run reconstituted, reclaimed oil at your own risk. The car companies are quite clear on this. All three national fleet service managers have said if the improper oil was a contributing factor in the engine failure, the powertrain warranty is gone and the liability is yours.

The second caveat with extended oil changes is you must have some way to get the officers to periodically check the oil. This was the hard lesson some departments learned with synthetic oil and their 15,000 change intervals. The cost savings from fewer oil and filter changes was more than offset by a higher frequency of blown engines. The synthetic oil didn’t cause the engine failures…running completely out of oil did!

Every car maker will tell you that in patrol use, an engine consuming up to a quart of oil every 1,500 miles is a normal condition! So if your hard charging traffic officers use a quart that often, in how many miles will the crankcase be empty? Normal oil consumption. No one checks the oil. Scheduled oil change interval. Run out of oil. Blown engine. What can you do to get them to check the oil just once between scheduled changes?

The third caveat gets back to idle time. On the Fords and Dodges, you need to consider the engine wear rate, confirmed by both Ford Fleet and Chrysler Fleet, of 33 miles per idle hour. (Both the CVPI and Charger now have idle hour meters.) The 5,000-mile change interval does not factor idle time. Just 30 hours of idle time equals 1,000 miles on the odometer.

According to a recent survey of Automotive Service Excellence (ASE) certified master automotive technicians, 84% said not getting a regular oil change can cause the most problems for a vehicle, compared to other maintenance issues. On second thought, since most police departments don’t followed the recommended oil change intervals, don’t tell anyone about the new, extended intervals. Let them think the oil needs changing every 3,000 miles. Maybe then it will actually be done by when it is supposed to!

Use the right oil. Check it regularly. Change it on time. That is the very essence of police fleet maintenance.

Ed Sanow is the editorial director for Police Fleet Manager. He can be reached at

Published in Police Fleet Manager, Jul/Aug 2008

Rating : 9.1

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