Enroll Now
Request Info
Whether you’re interested in becoming a diesel technician or drive a diesel truck yourself, it’s important to understand preventive maintenance and the purpose it serves.
Following a maintenance checklist is essential for maintaining your truck and keeping your equipment in good condition, which in turn protects the safety of both you and others on the road. Additionally, performing routine maintenance keeps repair costs to a minimum.
If you’re looking to learn more about diesel truck maintenance, you’ve come to the right place. Follow along as we share what preventive maintenance is, its importance and a complete diesel truck inspection checklist.
Diesel Truck Maintenance: Understanding the Basics
Preventive maintenance, when performed regularly, can extend the lifespan of diesel trucks and improve fuel economy. It can also play an important role in sustaining a truck’s value in resale, as buyers usually want to see the vehicle’s full maintenance record before making their purchase. For a commercial trucking application, performing regular maintenance will also avoid fines for Department of Transportation violations.
If you’re familiar with diesel trucks, you know that sudden mechanical breakdowns are expensive--however, they can often be avoided with routine inspections. These maintenance checks can be performed based on mileage or time.
While some might consider routine maintenance to be a waste of time, it saves money in the long run. Investing the time and money to keep diesel equipment in good condition optimizes fuel economy and prolongs usage of each part. Skilled
diesel mechanics
understand the importance of preventive maintenance and are able to complete the necessary inspections and repairs to keep their equipment running at the highest efficiency.
Diesel Truck Maintenance Checklist
Diesel truck drivers should follow a preventive maintenance checklist prior to hitting the road for each trip. This involves checking the important elements of the truck, including lights, tires, turn signals, hazard lights and much more. Those completing the inspection should watch out for unusual sounds and basic warning signs that indicate the need for repair, such as fuel contamination, oil oxidation or a black exhaust problem.
Follow along as we share a complete diesel truck inspection checklist, broken down by in-cab inspection, pneumatic system check, cab and body inspection, tire and wheel inspection, engine inspection, air brake inspection and hydraulic brake inspection.
In-Cab Inspection
The in-cab portion of a preventive maintenance check covers everything from the windshield to the foot pedals.
Check seat condition, seat suspension and seat belt operation
Check ignition key and start button
Check warning lights and alarms
Check interior lights (including dash and gauge illumination)
Check dash gauges
Check air gauges (and low pressure warning devices)
Check horn operation
Check A/C, heater and defroster controls
Check dash switches and accessory operation (PTO, cruise, etc.)
Check clutch pedal operation
Check automatic transmission selector/wiring
Check driveline parking brake operation
Check steering operation
Inspect sun visors
Check windshield and door glass for obstruction or damage
Check wiper/washer operation
Verify safety equipment decals, reflectors, flares and fire extinguisher meets FMCSR
Inspect floormat, gearshift and gearshift boot
Inspect foot pedals, pads and mounting
Pneumatic System Check
The pneumatic system uses compressed air to transmit and control energy. Checking this system involves everything from analyzing the air system for leaks to inspecting treadle valve operation.
Check air system for leaks (brakes released and applied)
Record governor specs
Check tractor protection valve
Test air pressure build-up time
Check air dryer operation (purge & cycle heater)
Inspect treadle valve operation (lube pivot and roller)
Inspect air compressor (leaks and air filter condition)
Cab and Body Inspection
The cab and body inspection covers a wide range of parts, from the air compressor to the bumpers.
Check air system for leaks (brakes released and applied)
Record governor specs
Check tractor protection valve
Test air pressure build-up time
Check air dryer operation (purge cycle & heater)
Inspect treadle valve operation (lube pivot and roller)
Inspect air compressor (leaks and air filter condition)
Inspect bumpers and license plate bracket
Inspect cab body floor and door seals
Inspect cab door locks, latches and hinges
Inspect roof and wind deflector mounting
Inspect towing/hitch device (pintle hook)
Inspect mudflaps/splash guards and brackets
Inspect/lube lift gate (if equipped)
Inspect fuel tank(s), mountings, crossover lines and fuel caps
Inspect exhaust system and mounting
Check HVAC air inlet filters and ducts (service as needed)
Inspect cab mountings, valve linkages and ride height (if equipped)
Lubricate all cab, body and hood grease fittings
Tires/Wheels Inspection
Checking a diesel truck’s tires is a critical step in the inspection process. This involves examining every tire to ensure it meets the requirements for tread depth and is properly inflated. This can help to avoid problems with alignment, traction, framework, braking and steering.
Front
Check wheel bearing and lube cap
Inspect for irregular wear patterns
Inspect for cuts and sidewall damage
Check and record valve stem caps
Inspect and record tread depth
Check and record tire pressure (psi)
Inspect for loose lug nuts
Inspect for cracked or damaged wheels
Rear
Check wheel bearings and axle flange seal for leaks
Inspect for irregular wear patterns
Inspect for cuts and sidewall damage
Check for dual mating with square
Check and record tread design
Check and record number of valve stem caps
Inspect and record each tread depth
Check and record each tire pressure
Inspect for loose lug nuts
Inspect for cracked or damaged wheels
Diesel Engine Maintenance Checklist
Without a properly functioning engine, a diesel truck can’t run. An engine inspection requires a closer look at everything from the power steering level to the engine cooling system. A full diesel engine inspection checklist includes the following:
Check radiator mountings for looseness or cracks
Check A/C condenser mountings for looseness or cracks
Check A/C compressor mounting and lines
Check for excessive play in water pump shaft
Check vibration damper for cracks, bulges, shifting or damage
Inspect coolant hoses and pressure test cooling system
Inspect coolant recovery system and pressure test radiator cap
Test and record antifreeze protection
Check alternator mounting and wiring
Check all accessory drive belts for condition and tension
Check power steering level/filter and hoses
Drain fuel/water separator (if equipped)
Check engine for leaks (oil, fuel and coolant)
Check air intake system, CAC, piping, hoses and clamps
Inspect turbocharger for leaks (visual inspection only)
Check engine wire harnesses, connectors and seals for damage
Obtain engine oil sample
Change engine oil and oil filters
Flush engine cooling system
Check operation of the engine fan clutch assembly
Service air filter only as needed, reset restriction indicator
Air Brake Inspection
An air brake inspection is only performed on trucks equipped with air brakes. Brakes are a critical element to inspect, especially before a long trip. A compressed air brake system is a type of friction brake in which compressed air presses on a diaphragm and applies pressure to the brake pad that stops the vehicle. The diaphragm in the brake chamber converts air pressure into mechanical force. These types of brakes are typically found in large, heavy vehicles, like diesel trucks.
Inspect front brake chambers and air lines
Inspect and record front brake lining/pad condition and thickness
Inspect and record front brake drum/rotor condition
Check operation of both front automatic slack adjusters (ASA)
Inspect rear brake chambers and air lines
Inspect and record rear brake lining/pad condition and thickness
Inspect and record rear brake drum/rotor condition
Check operation of all rear automatic slack adjusters (ASA)
Inspect trailer air hoses and couplers (tractors only)
Replace air drier dessicant cartridge (C-level inspection only)
Check operation of the hand brake valve (trolley valve)
Drain air tanks and check for contamination
Perform anti-lock brake system (ABS) operational self-test
Check ABS brake system wire harnesses and connectors
Check the automatic traction control (ATC) warning light
Inspect stop light operation
Lubricate all brake component grease fittings (optional)
Hydraulic Brake Inspection
A hydraulic brake inspection is only performed on trucks equipped with hydraulic brakes. Hydraulic brakes use fluid to charge the brakes. When the brake pedal is pressed, the increase in hydraulic fluid pressure forces the brake pistons to push the brake pad against the rotor or drum. This causes friction and slows the wheels to stop the vehicle.
Inspect front brakes and lines
Inspect master cylinder and fluid condition
Inspect power brake booster/hydrovac
Inspect all hydraulic lines, valves, hoses and fitting for leaks
Inspect and record front brake lining/pad thickness and condition
Inspect and record front brake/rotor drum condition and thickness
Inspect rear brakes and lines
Check driveline parking brake operation
Inspect pressure differential valve and warning light
Check HABS warning lamp indicator operation
Check hydraulic brake malfunction indicator lamp
Check proper brake pedal free travel
Check operation of the brake pedal: travel, effort and feel
Check operation of hydraulic brake booster system
Check operation of brake booster system
Check operation of brake booster back-up (reserve) system
Inspect HABS wiring harnesses, connectors for proper routing
Prepare for a Career as a Diesel Technician at UTI
At Universal Technical Institute, you can gain the fundamentals you need to service powerful trucks and engines while receiving hands-on training with equipment from leading brands in the industry.1
In addition to the 45-week
Diesel Technology program, we also offer a variety of
manufacturer-specific advanced training programs. This training can take your knowledge to the next level and help prepare you for a career working in a particular industry or for a certain manufacturer.
To learn more about training at UTI,
request information today. We’ll get you in touch with an Admissions Representative who can help guide you on your journey to becoming a technician!
UTI Campuses That Offer Diesel Mechanic Training
Universal Technical Institute of Illinois, Inc. is approved by the Division of Private Business and Vocational Schools of the Illinois Board of Higher Education.