6 Tips on AC System Maintenance for Diesel Trucks 

In the peak of the hot summer months, a functioning AC becomes a must-have in diesel trucks, and with vehicles dating back to 1969 boasting air conditioning units, today’s expectation is a cool 50% more efficiency. Checking regularly to ensure everything is running properly is crucial; a malfunctioning temperature gauge can signal a deeper problem within the electrical system which affects the AC’s capability. 

Noises like clicking or squealing under the hood serve as audible indicators. Pointing out an electrical problem or a worn belt that needs replacing, suggesting . Types of DIY maintenance and instances when professional service is necessary to keep it cool. Whether you’re learning to maintain the system yourself or leveraging 99% professional expertise. Your attention to maintenance ensures that you continue reading. The road ahead comfortably, without the anxiety of an AC that just stops working.

How The AC System Operates

To demystify the AC unit in your Diesel Engines Last Longer, let’s begin by populating our mental sketch with the pivotal compressor. A heart robustly driven by an engine-connected belt, rhythmically circulating the gaseous refrigerant under high pressure. The hot, pressurized refrigerant then travels to the condenser, a network of tubes where heat is ejected outwards. And moisture is left behind as condensation, transforming it from a gas to a liquid form.

 Nestled within the system is the receiver-drier, akin to the silica gel packets you find sheltered in new shoe boxes, it utilizes desiccants to absorb water and ensure that no particles or rogue moisture, which could form ice, endanger the system’s integrity. Approaching the heart of the cooling process, we encounter the thermal expansion valve (TXV) or orifice tube, where the liquid refrigerant’s pressure gets meticulously regulated.

 True to its name, the TXV allows an exact amount of refrigerant to pass through, engaging in expansion as it enters the evaporator; an intricate transformation occurs here—liquid refrigerant absorbs the cabin’s heat and humidity, only to boil into vapor. The blower propels air over the evaporator, stripping away warmth and humidity from the vehicle cab, ushering in cool air towards the front. 

Completing the cycle, the accumulator gathers any excess refrigerant, safeguarding the compressor as the entire system smoothly turns off and on, a movement orchestrated by meticulous pressure detection, to regulate the temperature inside the truck’s living space. This grand symphony of cooling is routine, yet extraordinary—a marvel I mull over every summer when the fierce sun challenges the tranquility of my own rig’s cockpit.

AC System Maintenance

Regular maintenance of AC systems is important to prevent damage that could lead to bigger issues. Tips for maintaining and fixing your truck’s AC include knowledge on how various elements work together for better performance.

Recharge The System

Recharging the system every few years involves replenishing your car’s AC with the appropriate type of refrigerant and lubricant, which helps in keeping the AC moving smoothly, acting as a sealant and heat remover within the condenser.

Air Filter Maintenance

To maintain a clean air filter in your truck, it is recommended to replace it every year and locate the filter itself beneath the dash or behind the glove box compartment. It’s crucial to remove any debris, run it under water, and wait for it to dry before putting it back to ensure the evaporator continues to deliver cool air without circulating dirt and other debris.


The refrigerant requires special attention as it circulates through various components, cooling the air before it enters the cabin. Therefore, it should be regularly replenished to keep the system working efficiently; the average truck air conditioner may need to be topped up or replaced every two years.

Run weekly

Running your air conditioner weekly for 10 minutes can avoid moisture and moss build-up, ensuring fresher, cooler air is delivered and keeping the gas pressure at an optimum level to reduce mechanical problems.

Unclog Debris

Debris caught in small grills near the windshield or front grille can clog the condenser and radiator; consider power washing under the hood or requesting this the next time you visit a car wash.

Routine Runs

It’s beneficial to run your AC system for 10 minutes once a week, even during the colder months, using the coldest and highest settings. This helps in maintaining proper gas pressure and ensures that the compressor continues to run correctly.

No Cool Air?

If no cool air is being emitted, it could be due to low refrigerant levels, a broken fan, or issues with the compressor or condenser. When the AC is on the highest setting and you hear a loud click, it could imply that the system has sufficient refrigerant; if the click continues, there may be leaks that need professional service for a recharge.

Regular Service

Having your truck’s AC system serviced every 4 to 5 years includes recharging by professionals who will check every part for leaks or other problems. It is normal for water to accumulate and drip from the evaporator due to humidity in the air turning into condensate as it cools and builds up.


In conclusion, diligent attention to AC system maintenance in diesel trucks is non-negotiable, especially when considering the sweltering heat of summer drives. From the intricate workings of the compressor and the critical role of refrigerant to the essential routine of running the AC weekly to prevent clogs and condensation issues, each detail contributes to the overall efficiency and longevity of the system. 

Regular filter changes, system recharge, and debris removal, coupled with professional check-ups every 4 to 5 years, form a robust defense against malfunctions and inefficiencies. Armed with these six tips, truck drivers and fleet owners can ensure that the refreshingly cool breeze of their AC units remains a reliable and welcome companion throughout the hottest of journeys, thereby ensuring a comfortable and uninterrupted driving experience.


What regular maintenance should be done on a diesel truck?

Stay on top of diesel engine maintenance with this simple-to-follow checklist.

  • Change oil and filters regularly.
  • Check and preserve water control components.
  • Keep water out of the fuel tank.
  • Maintain fuel injectors.
  • Check the alternator, radiator, compressor, and condenser mountings for looseness or 


What are the preventive maintenance of diesel engines?

Replace the Oil and Air Filters – To keep your engine running like a well-oiled machine, the oil and air filters will need replacing regularly. The filter casings are cleaned by a good diesel mechanic before installing the new filters. Lastly, the correct grade of diesel oil should be used for your vehicle.

What not to do with a diesel engine?

8 Common Ways of Harming a Diesel Engine

  • Clogging Your Fuel Filter. 
  • Not Changing Your Air Filters. 
  • Air Leaks in Fuel Injector Nozzles. 
  • Not Changing Your Oil. 
  • Towing Too Heavy. 
  • Too Many Short Start-Stop Trips. 
  • Not Cleaning a Dirty Diesel Engine. 
  • Not Changing Your Coolant.

How often do semi trucks need maintenance?

Most carriers and manufacturers recommend scheduling dry preventive maintenance – or “PM A” – every 10,000 to 25,000 miles. Dry preventive maintenance services typically include: Inspection of major components. Fluid refill (coolant, brake fluid, windshield fluid, etc.).

What is the basic maintenance of an AC system?

5 steps to stay aware of to maintain your air-conditioner easily: 

  • Get the air filter washed and cleaned. 
  • Get the coils cleaned. 
  • Ensure that the Condenser Unit Fan is in Proper Condition. 
  • Get the Condensate Drain inspected. 
  • Regular Professional Maintenance.