A used diesel truck can set you back a lot of money, so you’ll want to make sure you’re buying a vehicle that isn’t mechanically or structurally flawed.
Getting a full picture of your new truck through a pre-purchase inspection will help you avoid devastating problems like oil leaks, contaminated fuel systems, or worn-out belts. For example, diesel fuel absorbs more water than petrol. This can lead to contamination and sludge building up in your fuel tank. Issues like this can get pricey very quickly.
Getting your pre-purchase inspection done by a professional mechanic can help you spot common problems early. Regular maintenance will help you avoid unexpected breakdowns and save you money on fuel and repairs.
Understanding Diesel Engine Basics Before Inspection
Diesel engines work quite differently from petrol engines, so it’s recommended that you get a basic understanding of how diesel engine components work and what they do.
For starters, diesel engines use compression ignition instead of spark ignition to run. The cylinder block sits at the heart of a diesel engine. It holds the cylinders and supports many other parts. The pistons compress air inside these cylinders to create heat that makes combustion possible. The fuel injectors play a vital role in engine performance by spraying fuel straight into the combustion chamber.
The turbocharger improves engine efficiency. It pushes more air into the combustion chamber, which creates a stronger burn. The cooling system keeps the engine at the right temperature. It uses a radiator and water pump to stop the engine from overheating and getting badly damaged.
Common Diesel Engine Problems
You should know about common diesel engine problems before you schedule a pre-purchase vehicle inspection.
Fuel contamination is one of the most dangerous issues because diesel fuel attracts water at the molecular level. Water can rust fuel lines, injection pumps, and injectors from the inside.
Every diesel engine vibrates because of the strong combustion forces. However, these vibrations might get worse over time and could lead to bigger problems. Black exhaust smoke often means the engine isn’t burning fuel properly or the turbocharger isn’t working right.
The electrical system needs special attention too. Batteries and glow plugs can fail and make the engine hard to start, especially in cold weather. Coolant leaks, broken engine fans or stuck thermostats can make the engine too hot. This heat could warp the cylinder head.
Basic knowledge helps you ask the right questions and spot warning signs during car inspections. Diesel truck pre-purchase inspections work better when you know which parts need to be checked and the symptoms that might reveal serious problems underneath.
Essential Tools for Pre-Purchase Inspections
Professional mechanics use specialised diagnostic equipment to perform mobile pre-purchase inspections.
A quality diagnostic scanner is essential for any mobile pre-purchase vehicle inspection. These devices plug straight into the engine’s computer system and read fault codes that show potential problems.
Compression testing tools measure cylinder pressure to assess the engine’s internal condition and reveal important details about piston rings, valves, and overall engine health.
Other simple inspection tools include voltage metres to test electrical systems, coolant testers and oil analysis equipment. The electrical inspection must verify proper voltage, secure connections and ensure the starter motor’s efficient cranking with correct current draw.
Regular software updates keep diagnostic tools in sync with new vehicle technologies and codes. Tools with regular updates maintain accuracy as vehicle systems evolve during mobile pre-purchase inspections.
Step-by-Step Mobile Inspection Process
A detailed pre-purchase inspection can take up to 3 hours. The time varies based on the engine’s type, size, and location. Getting a professional review gives you valuable insights into the vehicle’s condition before you commit to buying.
Step 1: Comprehensive Visual Examination
The inspection begins with a thorough visual assessment by expert technicians. They check for:
- Signs of wear, corrosion, damage or leaks that could affect performance.
- Components across the entire vehicle, from passenger seat mounting to rear U-Bolts and everything in between.
Step 2: Fluid Analysis
Fluids play a crucial role in engine performance and longevity. Technicians conduct detailed tests on:
- Engine oil and fuel for contamination or water dilution.
- Coolant and brake fluid to determine their current state and when they need replacement.
- High-pressure fuel systems, ensuring water content stays below 500ppm (0.05%) to prevent damage to essential components.
Step 3: Compression Testing and Electrical System Inspection
Compression testing is essential for evaluating cylinder function, engine health, and efficiency. Additionally, technicians examine:
- Battery condition, wiring, and electrical connections to identify potential reliability issues.
Step 4: Road Test
If the vehicle is registered and insured, the inspection includes a road test to assess real-world performance.
- Mechanics listen for abnormal noises, feel for unusual vibrations, and evaluate the engine’s overall responsiveness.
Step 5: Computer Diagnostic Scanning
Advanced diagnostic scanners provide deep analytical insights into the vehicle’s systems, including:
- Electronic components such as airbags and anti-lock braking systems (ABS).
- Engine control unit (ECU) data, sensor readings, and system performance metrics.
Step 6: Service History Verification
To build a complete picture of the vehicle’s maintenance background, technicians:
- Review logbooks for recorded service history.
- Contact previous mechanics listed on service stickers for further insights.
Step 7: Detailed Inspection Report & Recommendations
The inspection concludes with a comprehensive report outlining:
- The current condition of the engine and all critical components.
- Any faults, potential risks, and necessary repairs identified during the assessment.
- Expert recommendations to help you make a well-informed purchasing decision.
Invest in the Best Equipment Possible with a Pre-Purchase Inspection from Kel Stanton’s Mobile Diesel Service
A pre-purchase inspection can protect you from pricey repairs and unexpected breakdowns.
At Kel Stanton’s Mobile Diesel Service, we will travel to you, wherever you are in South East Queensland, to carry out your diesel pre-purchase inspection or truck breakdown service.
If you’re buying from interstate and can’t inspect the vehicle in person, we can inspect it for you. This ensures you know exactly what you’re getting before picking up your equipment.
We value transparency and honesty. If your intended purchase needs diesel repairs, we’ll let you know right away.
Contact our mobile diesel mechanical team for a pre-purchase inspection today.