Light Trucks: Diesel Engine Maintenance Tips

Diesel Engine Maintenance, Light Trucks, Glow Plugs, Fluids, Filters, GasketsThere are a lot of options out there these days when shopping for a light-duty truck with a diesel engine. It doesn’t matter if you choose a Chevy, Ford, GMC, or Jeep; that baby will need routine maintenance to keep it running like a champ. Below, you’ll find several diesel engine maintenance tips for light trucks. From gaskets to glow plugs, plus fluids and filters, there is enough information to keep you in your garage all weekend.


Light Trucks: Diesel Engine Maintenance Tips

Check out these simple tips if you are handsy with your light truck and like to do all the work yourself. If you prefer to use a full-service auto center for all your maintenance needs, no one will fault you for it.


Like gasoline-powered vehicles, diesel-powered light trucks require regular fluid checks, flushes, and refills. Unlike gasoline-powered vehicles, diesels have a few extra fluids to service. Since maintenance intervals can vary widely between makes, models, and years, follow the factory recommendations found in your vehicle’s manual. Here’s a quick list of fluids to check:

  • Coolant – Engine coolant should be checked for acidity regularly, topped off when low, and flushed & refilled when necessary.
  • Diesel Exhaust Fluid (DEF) – A by-product of diesel engines is NOx gas in the exhaust. This gas contributes to unhealthy air quality. DEF is a combination of H2O and urea. It is used within the diesel exhaust system, turning the toxic NOx gas into cleaner emissions. 
  • Engine Oil – Diesel engines rely on clean oil for adequate lubrication of the engine’s components. Neglecting oil changes can do extensive damage to your vehicle’s engine.
  • Fuel – Diesel fuel comes in many grades, and depending on availability, you may need to use a fuel additive to keep your engine clean and running smoothly.
  • Gear Oil – Light-duty trucks that regularly perform heavy-duty tasks should inspect the gear oil in the axles.
  • Transfer Case Fluid – Four-wheel drive trucks need occasional transfer case fluid maintenance. Check your manual for estimated time intervals and adjust accordingly based on your usage. 
  • Transmission Fluid – Towing toys or hauling heavy loads can mean you need to change out your transmission fluid more frequently. Contact your service technician if you have questions about adjusting your routine maintenance schedule.


Filters perform a vital function in your light truck. They filter out impurities, improve the flow of air and fluids, and keep your diesel engine happy. Follow your owner’s manual recommendations for brand, size, and replacement intervals.

  • Engine Air Filter – relatively inexpensive and easy to change out. An air filter keeps damaging particles out of the engine components.
  • Fuel Filters – there is usually a primary and a secondary filter. Replace them at the same time.
  • Oil Filters – most diesel engines store a lot of oil. Stick to the manufacturer’s recommendations regarding time and mileage markers. A dirty oil filter leads to contaminated oil, which can severely damage a diesel engine.
  • Water Filter (Water Separator) – this filter removes impurities from the fuel. Newer model diesel trucks have dash indicator lights to signal you when to change this filter.


Gaskets play a vital role in diesel engines. Proper maintenance includes closely monitoring your vehicle’s gaskets and tracking all leaks to their source. Diesel engines need an enormous amount of pressure to create combustion. Replace leaking and damaged gaskets immediately.

Glow Plugs

Modern diesel engines utilize glow plugs to warm up the combustion chamber. These little guys are essential in colder climates or during the winter months. They perform the same function as spark plugs in gasoline engines.


The diesel compression-combustion engine uses a lot of power to start. There are usually two batteries to provide adequate power to the necessary components. The life cycle of your light truck’s batteries can vary depending on weather and usage. Be sure to monitor your batteries, clean the connections, and recharge them when necessary to help prolong their life.

Schedule a Diesel Engine Maintenance Service 

While the above tips can be helpful, they don’t cover your light truck’s entire diesel maintenance requirements. Call Wentworth Automotive at (858) 541-1044 for a comprehensive multi-point inspection, or visit our website to schedule your service.