Establishing Mileage Intervals

June 22, 2010

When it comes to establishing mileage intervals, one size does NOT fit all…

The general rule on preventative maintenance is that each agency should be bringing in their vehicles for inspections at predetermined mileage intervals following either the OEM guidelines or FDOT guidelines.  The OEM maintenance guidelines appear in the manual that is delivered with each new vehicle and include the minimum maintenance requirements that must be followed for the vehicle to qualify for warranty repairs.  Once a vehicle no longer qualifies for warranty repairs, an agency must determine what mileage intervals are appropriate to bring their vehicles in for inspection.  FDOT recommends that each agency bring in their vehicles for inspection at a maximum of every 6,000; 12,000; and 24,000 miles using the ABC inspection format.

It is a mistake to believe that one preventative maintenance schedule fits all vehicle fleets.  What works for one agency may be too much or too little for another.  Making adjustments to your PM inspection intervals is a combination of science and trial and error and the intervals should only be changed in short increments until you determine what is best for your particular fleet.   The first step includes conducting an engine oil analysis and checking to see how much residual lubricant is present in unsealed joints at each PM inspection.  If the oil analysis shows the oil is still good and there is still plenty of lubricant in each joint, as well as the fleet showing a good failure history, then you have good reason to consider extending the PM inspection interval.  If it shows the opposite, then you should decrease the intervals.

All good maintenance departments should have maintenance plans in place that describe current practices and should also describe any practices that are outside of the general fleet maintenance guidelines.  They will use the OEM and FDOT guidelines as a base line and then analyze trends, failure rates, life cycles and fluid analyses to determine what adjustments, if any, need to be made to obtain maximum life cycles while controlling cost.  If your agency has any questions on establishing PM inspection mileage intervals, please contact our office for guidance.