Alonso Diesel Services

Engine Diagnostics

Stay ahead of regulations and keep your fleet running at peak efficiency with expert Engine Diagnostics services. Our professional installation and maintenance solutions provide the insights you need to maintain compliance, reduce downtime, and streamline your trucking operations. What's included:

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• Computerized Engine Scanning - Use of advanced diagnostic tools to read fault codes from the engine control module (ECM).

• Visual Inspection - Check for obvious signs of damage, leaks, worn parts, or loose connections.

• Fuel System Testing - Evaluate fuel injectors, fuel pumps, and fuel lines for proper operation and pressure.

• Air Intake System Check - Inspect air filters, turbochargers, intercoolers, and intake manifolds for blockages or leaks.

• Exhaust System Analysis - Check for restrictions, leaks, or damage in exhaust components including EGR and DPF systems.

• Compression Testing - Measure cylinder compression to assess the condition of pistons, rings, and valves.

• Glow Plug and Ignition System Testing -  Verify glow plug function and ignition components to ensure proper cold starts.

• Sensor and Actuator Testing - Assess sensors (oxygen, temperature, pressure) and actuators (valves, injectors) for correct function.

• Battery and Electrical System Check - Test voltage, charging, and starting systems that impact engine performance.

• Fluid Analysis - Inspect engine oil, coolant, and other fluids for contamination or degradation.

• Road Test and Performance Monitoring - Evaluate engine behavior under load to identify intermittent or load-related issues.

• Review Diagnostic Trouble Codes (DTCs) - Interpret codes and sensor data to pinpoint specific faults or maintenance needs.

DOT Inspections

We provide on-site DOT inspection services for heavy-duty and medium-duty trucks, fleets, RVs, and trailers. Our certified inspections ensure your vehicles meet all Department of Transportation (DOT) standards—keeping your operations safe, legal, and on the road.

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• Brake System Inspection: Check the functionality and condition of brake pads, drums, linings, and air brake systems to ensure reliable stopping power.

• Tire and Wheel Inspection: Assess tire tread depth, inflation, and overall condition, along with wheel integrity and lug nut tightness.

• Steering and Suspension: Evaluate steering components and suspension systems for wear, damage, or misalignment affecting vehicle handling.

• Lighting and Reflectors: Verify that all headlights, taillights, brake lights, turn signals, and reflectors are operational and compliant.

• Exhaust and Emissions: Inspect exhaust systems for leaks or excessive emissions to meet environmental regulations.

• Fuel System Check: Look for leaks or damage in the fuel tanks, lines, and caps.

• Safety Equipment: Ensure fire extinguishers, emergency triangles, seat belts, and other required safety gear are present and functional.

• Frame and Underbody: Check for cracks, corrosion, or damage to the vehicle’s frame and undercarriage.

• Windshield and Mirrors: Inspect glass for cracks or damage and confirm mirrors are properly mounted and aligned.

• Horn and Wipers: Test horn operation and windshield wipers for effectiveness.

• Our thorough DOT inspections help prevent costly violations and downtime by identifying issues before they become major problems. Schedule your on-site DOT inspection with us to keep your fleet compliant, safe, and road-ready.

CARB Clean Truck Check

Ensure your vehicles meet California Air Resources Board (CARB) regulations with our specialized Clean Truck Check compliance testing. We conduct thorough assessments of your vehicle’s emissions-related systems to identify any issues and help you stay compliant with state environmental standards.

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• Thorough inspection of emissions-related components for proper function

• Diagnostic testing using advanced scan tools to detect faults or malfunctions

• Verification that all emissions control devices meet CARB standards

• Identification and reporting of any required repairs or maintenance

• Documentation to help you pass state inspections and avoid fines

• By ensuring your truck passes the CARB Clean Truck Check, you not only comply with the law but also contribute to cleaner air and better engine performance. Trust [Your Shop Name] to keep your fleet environmentally responsible and running efficiently.

Preventive Maintenance

Preventive maintenance is the key to keeping your diesel trucks running reliably, efficiently, and safely. We offer comprehensive preventive maintenance programs designed to reduce downtime, extend vehicle lifespan, and help you avoid costly repairs. We perform routine inspections and service tasks that catch small issues before they become major problems—keeping your fleet road-ready and compliant with industry regulations.

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• Oil & Filter Changes – Keep your engine running smoothly and extend its life.

• Brake System Checks – Ensure reliable stopping power and identify wear early.

• Fluid Level Checks & Top-Offs – Maintain proper levels for coolant, brake fluid, transmission fluid, and more.

• Tire Rotations & Inspections – Promote even tire wear and improve safety.

• Light & Signal Inspections – Make sure all exterior lights are working for safety and compliance.

• Battery Inspections & Replacements – Prevent breakdowns with reliable power diagnostics.

• Belt & Hose Inspections – Catch wear and damage before it leads to failure.

Diesel Truck Repairs

When your heavy-duty diesel truck needs expert repairs but downtime isn’t an option, our mobile mechanic services come to the rescue. We bring a fully equipped service unit directly to your job site, fleet yard, or wherever your vehicle is located—so you can get back on the road faster. We come prepared with advanced diagnostic and repair tools, enabling us to perform a variety of services, from routine maintenance to complex engine and powertrain repairs. This eliminates the need to tow your truck to a shop, saving you time, reducing operational disruptions, and cutting costs. Whether it’s emergency repairs, scheduled maintenance, or compliance checks, we are ready to provide fast, reliable service tailored to the unique needs of heavy-duty diesel trucks, trailers, and commercial vehicles. We offer comprehensive services to keep your diesel trucks running at peak performance, including:

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• Fuel System/Injectors – Restore fuel efficiency and performance with expert service.

• Valve Adjustments – Ensure proper engine timing, smooth performance, and fuel efficiency with precise valve lash adjustments performed to manufacturer specifications.

• Turbocharger – Maintain power and efficiency with professional turbo service.

• Brake System – Ensure safe and responsive braking with expert repairs.

• Cooling System – Prevent overheating and maintain optimal engine temperature (i.e. radiator, water pump, thermostat).

• Electrical System – Diagnose and resolve wiring, starting, and charging issues.

• Transmission Services – Keep your transmission operating smoothly and reliably.

• Suspension Repairs – Improve ride quality and vehicle stability with professional suspension work.

• Wheel Seal/Bearing Replacements – Eliminate noise and restore smooth, safe wheel operation.

Emissions & Aftertreatment System Services

Keeping your diesel engine’s emissions systems in top condition is essential for compliance with environmental regulations and maintaining optimal engine performance. We specialize in comprehensive Emissions & Aftertreatment System Services designed to reduce harmful pollutants and improve fuel efficiency. We provide expert diagnostics, repairs, and maintenance on key emissions components, including:

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• Diesel Particulate Filter (DPF) Cleaning & Replacements – Improve fuel efficiency and reduce emissions with thorough DPF maintenance.

• Selective Catalytic Reduction (SCR) Repairs – Ensure effective NOx reduction and compliance with emissions standards.

• EGR Valve Cleaning & Replacement – Reduce emissions and improve engine efficiency by restoring proper exhaust gas recirculation function.

• Exhaust System – Ensure proper emissions control and engine performance.

• Manifold Repairs – Restore proper airflow and prevent exhaust leaks to maintain engine performance.