Failure to provide timely maintenance on a turbo-charged diesel engine can result in some expensive repairs, especially if it involves replacing a turbocharger or engine. The inexperienced may not realize how important some of the basic services are when servicing these applications. The turbo-diesel engines require a greater volume of air compared to a normal aspirated engine. Diesel applications should be serviced by an experienced technician who has a trained eye for symptoms or conditions that could lead to serious damages. A common mistake is the misinterpretation of what constitutes a general service or severe service vehicle and the required maintenance interval. Many vehicles fall into a severe service category but are not serviced accordingly. Following are some conditions that require a severe service maintenance schedule:
1) Extended idling or slow speed stop and go conditions.
2) Commercial use vehicles, delivery service, etc.
3) Vehicles operated in excess of normal highway speeds on a continual basis.
4) Extended driving in extreme temperatures such as 90 degrees F or higher.
5) Short trip driven vehicles.
6) Off-road vehicles or vehicles operated in dusty or sandy environments,
such as construction or farm use.
7) Tow trucks, pulling trailers or hauling heavy loads.
8) Short trip driven vehicles operated in extreme cold conditions such as 32 degrees F or lower.
Mileage is not always the key for maintenance, as vehicles operated on construction sites or farms may require an air filter replacement in 3000 miles or less. A restricted air filter can result in the turbocharger pulling the filter media from the filter and consuming it or damaging the filter seal, allowing unfiltered air to enter the turbocharger or engine, resulting in a catastrophic failure. A quick inspection can reveal much about the integrity of the air cleaner system. Following are some areas that need a close inspection:
Filter Housing: Examine the integrity of the filter housing for any distortion or damage that could result in unfiltered air entering the turbocharger or engine, promoting premature wear.
By-Pass: Examine the filter seal and air box lid for dust streaks or trails, which would indicate that air is by-passing the filter.
Dusting: Extreme filter contamination can result in debris being pulled through the filter media. When dusting occurs, there will be evidence of debris on the clean air side of the filter housing.
Latches or Retainers: Examine the integrity of all latches and retainers to make certain the filter is properly sealed in the housing. Never pull a filter into position with the latch or retainer as this can damage the air box or latch. Never let a vehicle leave your shop with a filter that is not properly sealed in the housing without documentation on the repair order. A broken latch can result in damage to the engine or turbocharger, and you do not need that liability.
Vehicles operated in heavy rains or flood conditions are subject to the same symptoms as a filter restricted with debris. The water results in a hydro-lock condition restricting airflow to the engine. When this occurs, the engine may encounter a stalling condition. The filter housing can collapse, or the filter can be sucked into the housing, resulting in unfiltered air entering the engine. Often, the filter disintegrates and is consumed by the turbocharger and engine, causing expensive repairs.
Snow can create the same symptoms as a filter heavily contaminated with debris or water. The engine may encounter a loss of power, stalling, Malfunction Indicator Lamp illumination, or a Power Reduced message may be displayed. The snow conditions can be elusive for the technician attempt-ing to make a diagnosis. Often, the vehicle is towed in and placed in a warm shop where the evidence quickly melts and evaporates, removing all clues. Replace any filter that has been contaminated with water or snow, as the integrity of the media is questionable.
Make the air filter and related housing a part of your inspection when servicing the vehicle. The presence of debris or even a large bug hitting a compressor wheel spinning at 130,000 RPMs or more can cause a lot of expensive damage.