Scheduled maintenance is just that, it is required maintenance that you can schedule in at your convenience. If there were a "silver bullet" to extending vehicle life, reliability and maintaining fuel economy this is it. This required maintenance affects all aspects of the vehicle from simple fluid exchanges to more extensive engine repairs (timing belts, valve adjustments, etc.) Not all vehicles require the same maintenance nor do they fall into the same mileage intervals. Information regarding the service requirements and mileage intervals can usually be found in the owner's manual or by contacting your auto care provider.
Use of the owner's manual for service intervals can be misleading. In many cases we find that the services and mileage intervals in the owner's manual do not provide the optimum care for your vehicle. In many cases, very important services are left out or considered to be "life time" or have very extended mileage intervals. This is most commonly seen for fluid exchanges. Many manuafacturers have extended or deleted these services to provide a false picture of yearly maintenance expenses to make their vehicle seem "cheaper" to operate. The reality is that by following some of these guidelines, you may face major expenses down the road that could have been been prevented (preventative maintenance) had the proper servicing been performed. So, in the long run, a very well maintained vehicle along the way will be less expensive to operate and be more reliable. With this in mind, a proper mix of the owner's manual information and the recommendations of your service provider should be followed. We will cover most of the different types of maintenance associated with the different systems.
Dependant upon the manufacturer, engine maintenance can be minor oil changes to more complex timing belts and valve adjustments.
- Engine Oil Changes
Mileages vary from 3,000 to 15,000 miles, dependant upon the vehicle and the oils used. At the time of these services, a complete vehicle inspection should be performed to "catch" problems before they become major or dangerous. These inspections should be performed every time.
The days of "tune-ups" are gone. Due to the extensive use of computer controls, a modern-day "tune-up" generally requires an inspections of the related components and replacement of only the needed parts. These would include: spark plugs, ignition wires, ignition coil(s), all filters, PCV systems, fuel injection/computer and emission control inspection.
- Engine Cooling System Maintenance
This varies from coolant changes to waterpump, hoses and thermostat replacement. Failure to maintain these systems can lead to major engine failure that can occur very quickly, sometimes in less than a few miles.
- Timing Belts
Not all engine use a timing belt, yet some use more than one. If your vehicle uses a timing belt, the mileage interval for replacement is critical. If a timing belt breaks, it can lead to severe engine damage. At the time of a timing belt replacement it is also critical to inspect/replace the tensioner and pulley assemblies, and in most cases, the water pump and thermostat. It is also a good opportunity to inspect for oil leaks under the timing covers. If a timing belt becomes saturated or even wet with oil/coolant it will break prematurely.
- Valve Adjustment
Not all vehicles require periodic valve adjustments, but for those that do it is also very important. It is a misconception that "out of adjustment" valves are noisy; On the contrary they can become quiet. In the event that a vehicle is operated with valves that are out of specification the result can be severe cylinder head or engine damage.
Transmissions come in 2 basic flavors: manual and automatic. The maintenance side of both of these is usually just fluid and filter (if equipped) replacements. One of the largest challenges however is the many different types of fluids required. In some cases, fluids can exceed $50.00 per quart and may have capacities of 10qts or more. It is due to this expense that many manufacturers have chosen to "extend" the life of these fluid's changes in an attempt to reduce a consumer's operating costs. This can be a very expensive mistake. Contact your service provider to find out the "proper" maintenance schedule for the best reliable service. Remember, it is in the manufacturer's best interests to have a limited life expectancy for a vehicle. These expectations are never discussed or disclosed as they are just a part of the cycle of vehicles and should be expected.
Many newer cars are coming out with CVT-style transmissions (continuously variable transmission). Regardless of what the manufacturer calls them, they basically have a shiftless or smooth acceleration through a variable ratio band. These are used in an attempt to reduce vehicle emissions by reducing the engine RPM changes that would occur in older conventional shifting transmissions.
These transmissions have critical fluid requirements and it is important to change the fluids at reasonable intervals or failure will be imminent.
Transfer Cases and Differentials
Both of these are found in many different configurations. In most front wheel drive applications the differential is part of the transmission and doesn't require separate maintenance. In other applications, these componenets are separate and usually require no more than periodic fluid exchanges. These units will also have multiple fluid requirements that must be met on an individualized basis. Some of these components can achieve mileages over 500,000 without repair (with proper maintenance of course).
Heating and Air Conditioning
As far as heating is concerned, most maintenance is covered with engine cooling system maintenance. Most heating systems use the engine's coolant to provide heat.
Air conditioning can become very expensive as far as repair is concerned. The leading failure in A/C systems is lack of refrigerant oil to the compressor. This is usually caused by a low refrigerant level. Even without a failure, all systems leak, at the low end about 1/2 ounce per year in a sealed system. In our newer cars, total refrigerant capacities are as low as about 10oz. This means that even new systems should be periodically inspected and refrigerant levels maintained. Intervals very from car to car, but in a properly working system they should be inspected about every 3 years. At this point a replacement reciever/driver or accumlator is more than likely recommended.
Braking and suspension systems are less maintenance than repair but there are a few mileage/age maintenance items.
Front and rear suspension should be inspected at every oil change and lubricated if applicable. Along with the impact on tire wear, some components when warn can become dangerous. Some vehicles incorporate wheel bearings that require periodic re-packing or greasing. Consult your owner's manual for these intervals. Tires will require rotating every 5-6,000 miles or what we recommend at every other oil change. This should also include a brake inspection for wearing components.
Brakes need regular inspections (unless a problem is noticed). As for regular maintenance, the fluid should be flushed at least every 30,000 miles or at every brake service. Some systems need cleaning and adjustments performed usually at the time of the tire rotations.
Performing regular scheduled maintenance will increase the value and the reliability of your vehicle. These may seem expensive or not necessary at the time, but in the long run will be cheaper than ignoring them. This page only contains a brief explanation of regular items for service. In the event of warning lamps or anything else that seems out of the ordinary, contact your service provider immediately as continued driving could cause more damage.
Questions or want more information?
Various fuel injector types
G.M. "spider" multi-port fuel injector assembly
Lack of cooling system maintenance caused this Toyota to over heat and crack the cylinder head
Internal view of a typical front wheel drive transmission with internal differential
Lack of maintenance led to the failure of this 4L80E G.M. trans
This A/C compressor was destroyed due to lack of lubrication and improper use of "A/C system sealer"