wrenchesPreventive Maintenance Inspection (PMI) is a simple way to prevent costly repairs and breakdowns and maximize uptime. Done properly, it's a great low-cost, high-reward practice, whether you manage an entire fleet of trucks, or if you're an owner/operator with just one truck. PMI will improve your profitability and prevent customer service problems from missing schedule deliveries, and of course it increases safety as well.

Having a detailed PMI conducted by a knowledgeable, experienced technician can save you thousands of dollars. An improperly conducted PMI on the other hand, can cost you thousands and be a complete waste of time.

Changing your filters or your oil on a regular basis is only part of a good PMI program. To take full advantage of a preventive maintenance program, a PMI technician must be able to recognize the state and function of every system on a truck, and be comfortable with the electrical system, cooling, steering, regular and air brakes and all parts of the engine, chassis and cab. As an indicator of the technical knowledge required for PMI, there's an ASE T8 Certification for Preventive Maintenance Inspection included in their Medium/Heavy Truck Series.

Preventive Maintenance Inspection is an involved process and includes careful evaluation of the engine systems; inside the cab; electrical components and truck electronics; truck frame and chassis; and a road/operational test.

Starting with the engine, a PMI checklist includes things like the obvious: changing the oil and oil/air filters. It also calls for checking for oil, coolant, air, and fuel leaks and over two dozen other steps.

For the electrical systems PMI includes checking the charging output of the alternator, or the battery state-of-charge and condition, along with several other important inspections.

Under the chassis PMI calls for checking parking brakes or looking for leaks in the air system and checking the air pressure build-up time. All brake systems including lines need to be inspected for leads or damage. Some seals may show a small bit of seepage with telltale oil, fuel or coolant residue, but may be normal. A trained technician can tell you the difference between a true leak which needs to be serviced, and a small bit of seepage, avoiding unnecessary repair costs.

Proper lubrication is important for preventitive maintenance inspection, including flushing old grease and diagnosing potential problems. For example, when lubing U-joints, if the old grease is blackened it may be a sign of joint failure. The road/operational portion of PMI calls for testing operation of the clutch and gear shift, the road speed governor, the operation of all instruments, checking the steering wheel for play and centering, and so on.

The bottom line is your bottom line: take PMI seriously and in the long haul your profits will increase.

And remember to call HHP when you need service items to keep your truck on the road.