Heavy Duty Diesel Repair That Keeps Commercial Fleets Moving
Professional diesel diagnostics, repairs, preventive maintenance and fleet support for commercial trucks, tractors, trailers and heavy equipment.
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CRANETEC provides heavy duty diesel repair for commercial trucks, semi tractors, trailers, and heavy equipment, including complete diesel engine diagnostics, engine repair and overhaul, turbocharger and fuel injector service, cooling system repair, electrical and ECM diagnostics, emissions aftertreatment repair, preventive maintenance, and fleet maintenance programs. We service all major diesel manufacturers — Cummins, Detroit, PACCAR, Caterpillar, Volvo, Mack, and others — for transportation, utility, construction, municipal, and contractor fleets.
CRANETEC Heavy Duty Diesel Engine Repair
What diesel engine repair services does CRANETEC provide?
CRANETEC provides heavy duty diesel engine repair for commercial trucks, tractors, trailers, utility fleets, and vocational equipment. Services include computer diagnostics, fuel system and injector repair, turbocharger repair, cooling system repair, DPF cleaning, DEF and EGR service, and preventive fleet diesel maintenance. Experienced technicians, advanced diagnostic equipment, and fast turnaround keep your fleet compliant and on the road across Texas, Louisiana, Florida, and North Carolina. See our Heavy-Duty Truck Repair hub for the full service cluster.
Common Diesel Engine Problems
Recognizing symptoms early prevents a repairable issue from becoming a major failure. Call CRANETEC at the first sign of trouble.
| Problem | Symptoms | Recommended Repair | Urgency |
|---|---|---|---|
| Loss of Power | Sluggish acceleration, low boost, derate. | Fuel restriction, turbo, EGR, injectors, sensor. | Schedule |
| Hard Starting | Long crank, slow crank, intermittent start. | Batteries, starter, fuel pressure, glow plugs. | Schedule |
| No Start | Crank but no fire, or no crank at all. | Fuel supply, ECM, injectors, batteries, starter. | Schedule |
| Engine Overheating | Rising temp, coolant boil, white smoke. | Water pump, radiator, thermostat, head gasket. | Immediate |
| Oil Consumption | Frequent oil top-off, low oil pressure. | Worn rings, valve seals, turbo seal, leak. | Schedule |
| Oil Leaks | Oil on engine, drips, low level. | Gaskets, seals, cooler, high crankcase pressure. | Schedule |
| Fuel Leaks | Fuel smell, drips, low rail pressure. | Lines, injectors, pump, filter housing. | Schedule |
| Poor Fuel Economy | Dropping MPG, more fuel stops. | Injectors, filters, turbo, brakes, ECM. | Schedule |
| Engine Knocking | New metallic knock, bearing noise. | Bearings, injector imbalance, internal damage. | Immediate |
| Black Smoke | Heavy black exhaust under load. | Over-fueling, injectors, air restriction, EGR. | Schedule |
| Blue Smoke | Bluish smoke, oil burning smell. | Worn rings, valve seals, turbo seal. | Schedule |
| White Smoke | Persistent white smoke, coolant smell. | Injectors, head gasket, cracked head, DEF. | Schedule |
| Misfires | Rough idle, vibration, imbalance. | Injector, compression, harness, sensor. | Schedule |
| Low Oil Pressure | Warning light, low gauge reading. | Pump, bearings, sender, oil level. | Immediate |
| Coolant Loss | Frequent top-off, visible leak, overheating. | Radiator, hose, water pump, head gasket. | Schedule |
| Check Engine Light | MIL on or flashing, stored codes. | Emissions, sensor, fuel, electrical faults. | Schedule |
| Engine Derate | Reduced power, limited speed. | Emissions, coolant, oil, sensor fault. | Schedule |
| High Exhaust Temperature | High temp warning, frequent regen. | DPF restriction, dosing, sensor, EGR. | Schedule |
| Frequent Regeneration | Constant active regen, fuel loss. | Loaded DPF, NOx, EGR, injectors, fuel. | Schedule |
| Turbo Failure | Loss of boost, whining, oil in intake. | Oil starvation, contamination, FOD. | Schedule |
Loss of Power
Symptoms: Sluggish acceleration, low boost, derate.
Causes: Fuel restriction, turbo, EGR, injectors, sensor.
Consequences: Reduced productivity, derate, fuel waste.
Schedule diagnosticsHard Starting
Symptoms: Long crank, slow crank, intermittent start.
Causes: Batteries, starter, fuel pressure, glow plugs.
Consequences: No-start, stranded unit, lost hours.
Electrical & fuel diagnosticsNo Start
Symptoms: Crank but no fire, or no crank at all.
Causes: Fuel supply, ECM, injectors, batteries, starter.
Consequences: Totally disabled truck.
Emergency diagnosticsEngine Overheating
Symptoms: Rising temp, coolant boil, white smoke.
Causes: Water pump, radiator, thermostat, head gasket.
Consequences: Head warpage, cracked block.
Stop & call nowOil Consumption
Symptoms: Frequent oil top-off, low oil pressure.
Causes: Worn rings, valve seals, turbo seal, leak.
Consequences: Internal wear, low-oil failure.
Engine inspectionOil Leaks
Symptoms: Oil on engine, drips, low level.
Causes: Gaskets, seals, cooler, high crankcase pressure.
Consequences: Low oil, fire risk, mess.
Leak diagnosisFuel Leaks
Symptoms: Fuel smell, drips, low rail pressure.
Causes: Lines, injectors, pump, filter housing.
Consequences: Fire risk, low power, no-start.
Fuel system repairPoor Fuel Economy
Symptoms: Dropping MPG, more fuel stops.
Causes: Injectors, filters, turbo, brakes, ECM.
Consequences: Higher fuel spend, lower margin.
PM & diagnosticsEngine Knocking
Symptoms: New metallic knock, bearing noise.
Causes: Bearings, injector imbalance, internal damage.
Consequences: Catastrophic failure if driven.
Stop & call nowBlack Smoke
Symptoms: Heavy black exhaust under load.
Causes: Over-fueling, injectors, air restriction, EGR.
Consequences: Fuel waste, DPF loading, regen.
Injector & air diagnosisBlue Smoke
Symptoms: Bluish smoke, oil burning smell.
Causes: Worn rings, valve seals, turbo seal.
Consequences: Oil consumption, DPF damage.
Engine inspectionWhite Smoke
Symptoms: Persistent white smoke, coolant smell.
Causes: Injectors, head gasket, cracked head, DEF.
Consequences: Coolant loss, internal damage.
Head gasket & injector testMisfires
Symptoms: Rough idle, vibration, imbalance.
Causes: Injector, compression, harness, sensor.
Consequences: Derate, smoke, DPF loading.
Cylinder cutout testLow Oil Pressure
Symptoms: Warning light, low gauge reading.
Causes: Pump, bearings, sender, oil level.
Consequences: Rapid engine damage.
Stop & call nowCoolant Loss
Symptoms: Frequent top-off, visible leak, overheating.
Causes: Radiator, hose, water pump, head gasket.
Consequences: Overheating, head damage.
Cooling system diagnosisCheck Engine Light
Symptoms: MIL on or flashing, stored codes.
Causes: Emissions, sensor, fuel, electrical faults.
Consequences: Derate, failed inspection.
Code scan & diagnosticsEngine Derate
Symptoms: Reduced power, limited speed.
Causes: Emissions, coolant, oil, sensor fault.
Consequences: Cannot meet route commitments.
Diagnostic scanHigh Exhaust Temperature
Symptoms: High temp warning, frequent regen.
Causes: DPF restriction, dosing, sensor, EGR.
Consequences: Shutdown risk, fuel waste.
Aftertreatment diagnosisFrequent Regeneration
Symptoms: Constant active regen, fuel loss.
Causes: Loaded DPF, NOx, EGR, injectors, fuel.
Consequences: Performance loss, downtime.
DPF & emissions serviceTurbo Failure
Symptoms: Loss of boost, whining, oil in intake.
Causes: Oil starvation, contamination, FOD.
Consequences: Power loss, engine damage.
Turbo inspectionExperiencing any of these symptoms?
Call CRANETEC: (409) 752-5400Diesel problem? Get a fast diagnosis and clear repair plan.
Heavy Duty Diesel Repair Services
Full diagnostic, repair, and maintenance coverage for commercial diesel engines — from a single injector to a complete in-frame rebuild.
Complete Diesel Engine Diagnostics
OEM-level scan tools, live data, cylinder cutout and relative compression testing to pinpoint failures.
Warning Signs
Benefit: Eliminates guesswork and unnecessary parts.
Fleet impact: Faster, lower-cost repair.
Diesel Engine Repair
Component-level repair for fuel, turbo, cooling, electrical, and aftertreatment systems.
Warning Signs
Benefit: Restores power and reliability.
Fleet impact: Returns unit to service quickly.
Complete Engine Overhaul
Full teardown, inspection, and rebuild of worn major components.
Warning Signs
Benefit: Extends engine life without full replacement.
Fleet impact: Protects major investment.
In-Frame Engine Rebuilds
Bearings, pistons, rings, and head service with the engine in the chassis.
Warning Signs
Benefit: Lower cost than out-of-frame rebuild.
Fleet impact: Minimizes downtime and labor.
Out-of-Frame Engine Rebuilds
Block, crankshaft, and liner service requiring engine removal.
Warning Signs
Benefit: Restores block-level integrity.
Fleet impact: Returns engine to full service life.
Turbocharger Repair
Inspection, bearing, and seal service; boost and oil leak diagnosis.
Warning Signs
Benefit: Restores power and fuel economy.
Fleet impact: Prevents related damage.
Turbo Replacement
Correct turbo replacement with oil and air-intake root-cause correction.
Warning Signs
Benefit: Prevents repeat failure.
Fleet impact: Protects fuel system and engine.
Fuel Injector Testing
Balance, leak, and electrical testing of each injector.
Warning Signs
Benefit: Identifies the failed cylinder.
Fleet impact: Avoids replacing good injectors.
Fuel Injector Replacement
OEM-spec injector replacement with fuel system flush and filter service.
Warning Signs
Benefit: Restores combustion and economy.
Fleet impact: Reduces regen and smoke.
High Pressure Fuel Pump Repair
Diagnosis and replacement of HPFP and related system contamination.
Warning Signs
Benefit: Restores fuel delivery.
Fleet impact: Prevents injector damage.
Fuel System Repair
Lines, filters, pump, and rail repair with contamination inspection.
Warning Signs
Benefit: Restores pressure and economy.
Fleet impact: Protects expensive components.
Cooling System Repair
Radiator, water pump, thermostat, fan clutch, and CAC service.
Warning Signs
Benefit: Prevents catastrophic engine damage.
Fleet impact: Protects head and block.
Radiator Repair
Leak repair, flush, and replacement of restricted radiators.
Warning Signs
Benefit: Restores cooling capacity.
Fleet impact: Prevents overheating events.
Water Pump Replacement
Pump replacement with coolant flush and thermostat inspection.
Warning Signs
Benefit: Restores coolant circulation.
Fleet impact: Prevents belt and engine damage.
Oil Leak Repair
Gasket and seal diagnosis and replacement to stop active leaks.
Warning Signs
Benefit: Stops fluid loss and mess.
Fleet impact: Prevents low-oil damage.
Head Gasket Repair
Head gasket replacement with head inspection and resurfacing.
Warning Signs
Benefit: Seals combustion and coolant.
Fleet impact: Prevents major engine failure.
Cylinder Head Repair
Valve, seat, and crack inspection and rebuild or replacement.
Warning Signs
Benefit: Restores cylinder sealing.
Fleet impact: Extends engine life.
Valve Train Repair
Valve adjustment, lash, spring, and cam-following component service.
Warning Signs
Benefit: Restores proper valve timing.
Fleet impact: Improves efficiency.
Engine Harness Repair
Trace and repair opens, shorts, and high-resistance connections.
Warning Signs
Benefit: Eliminates electrical faults.
Fleet impact: Prevents derate and no-start.
ECM Diagnostics
ECM communication, calibration, and input/output testing.
Warning Signs
Benefit: Confirms ECM vs sensor fault.
Fleet impact: Avoids unnecessary replacement.
Electrical Diagnostics
Sensors, harness, and multiplexed system diagnosis using wiring diagrams.
Warning Signs
Benefit: Pinpoints electrical root cause.
Fleet impact: Reduces repeat failures.
Charging System Repair
Alternator, battery, and cable diagnosis and replacement.
Warning Signs
Benefit: Restores reliable starting.
Fleet impact: Protects ECM and electronics.
Starter Replacement
Starter testing and replacement with cable inspection.
Warning Signs
Benefit: Restores reliable starts.
Fleet impact: Reduces downtime.
Alternator Replacement
Output testing and alternator replacement.
Warning Signs
Benefit: Maintains system voltage.
Fleet impact: Protects electronics.
Battery Systems
Load testing, replacement, and cable service for multi-battery trucks.
Warning Signs
Benefit: Restores cranking power.
Fleet impact: Prevents no-start events.
Preventive Maintenance
Scheduled oil, filter, coolant, and inspection service.
Warning Signs
Benefit: Catches wear before failure.
Fleet impact: Lowers total cost.
Fleet Maintenance Programs
Custom PM programs with scheduling, reporting, and history.
Warning Signs
Benefit: Predictable uptime and cost.
Fleet impact: Long-term reliability.
Emergency Repairs
Priority diagnostic response for disabled or derated trucks.
Warning Signs
Benefit: Rapid return to service.
Fleet impact: Minimizes lost revenue.
Why Choose CRANETEC
Diesel Repair Built for Commercial Fleets
We do more than fix engines — we keep your operation running.
Commercial Fleet Expertise
We understand fleet uptime, route schedules, and DOT compliance — not just the engine.
Fast Turnaround
Priority diagnostics and repair planning get trucks back on the road quickly.
Advanced Diagnostic Equipment
Modern scan tools and live data find the real problem, not just the code.
Experienced Technicians
Skilled diesel techs with hands-on commercial experience across major engine brands.
Transparent Communication
Clear estimates and updates so you make informed decisions, no surprises.
Quality Replacement Parts
OEM and premium aftermarket parts selected for reliability and uptime.
Preventive Maintenance Focus
We help you prevent failures before they happen with scheduled service.
Reduced Downtime
Fewer breakdowns, faster repairs, and documented history keep fleets productive.
Equipment We Service
Diesel Engines We Repair
From line-haul tractors to vocational equipment, we keep your diesel-powered assets working.
Class 7 Trucks
Medium-heavy trucks and vocational units.
Class 8 Trucks
Heavy-duty trucks and over-the-road tractors.
Semi Tractors
Line-haul and regional tractors.
Commercial Fleets
Mixed fleets with priority scheduling.
Bucket Trucks
Aerial devices with diesel power plants.
Utility Trucks
Utility and telecom fleet trucks.
Service Trucks
Mechanic and service body trucks.
Construction Equipment
Diesel-powered equipment on the job.
Vocational Trucks
Dump, mixer, and refuse trucks.
Trailers with Auxiliary Diesel Systems
Reefer and auxiliary diesel units.
Repair Process
How CRANETEC Diesel Repair Works
A clear, six-step process from first call to back on the road.
Contact CRANETEC
Call or submit a request. Tell us the truck, engine, and symptoms.
Diagnostic Inspection
We read codes and test systems to find the root cause.
Repair Estimate
You get a clear estimate and scope before any work begins.
Professional Repair
Skilled technicians perform the repair with quality parts.
Quality Testing
We verify the repair with performance and road testing.
Return to Service
Your truck is back on the road — documented and ready.
Signs Your Diesel Engine Needs Service
Don't Ignore These Diesel Warning Signs
Early attention prevents small problems from becoming major repairs.
Black Smoke
Excess fuel or restricted air — injectors, EGR, or turbo.
White Smoke
Unburned fuel or coolant entering the cylinder.
Blue Smoke
Oil burning — worn rings, valve seals, or turbo.
Engine Knocking
Fuel, bearing, or injector issues that need prompt attention.
Low Oil Pressure
Worn bearings, oil pump, or leaks — stop and inspect.
Coolant Loss
Leak or head gasket issue risking overheating.
Poor Fuel Economy
Injectors, sensors, or fuel system out of spec.
Power Loss
Fuel, air, turbo, or emissions restriction under load.
Frequent Regeneration
DPF loading or exhaust restriction needs service.
Check Engine Light
Stored codes identify the system at fault.
Hard Starting
Glow plugs, fuel pressure, or cranking issues.
Unusual Vibrations
Misfire, mount, or rotating component problems.
Preventive Maintenance
Preventive Diesel Maintenance Reduces Failures and Cost
A scheduled preventive maintenance program is the most reliable way to lower diesel operating costs. Instead of reacting to failures, planned service catches wear early, extends engine life, keeps emissions systems healthy, and keeps your crews working. CRANETEC builds diesel maintenance programs tailored to your fleet size, usage, and DOT requirements.
Fewer Engine Failures
Scheduled service catches wear before it becomes a breakdown.
Lower Fuel Consumption
Clean filters and proper tune keep fuel economy at its best.
Less Unexpected Downtime
Plan service around your schedule, not around failures.
Lower Major Repair Costs
Preventive care avoids expensive, avoidable overhauls.
Featured Case Studies
Real Diesel Repair Results
Representative diesel repair and maintenance outcomes for commercial fleets.
Diesel Engine Diagnostics
Live-data diagnosis isolated a faulty NOx sensor causing repeated derates — fixed in one visit.
Injector Replacement
Flow-matched injector set restored power and fuel economy on a line-haul tractor.
Turbocharger Repair
Replaced worn turbo and corrected boost leaks to end power loss under load.
DPF System Repair
Cleaned DPF and serviced DEF doser to clear warnings and restore compliance.
Fleet Preventive Maintenance
Scheduled PM program cut a 20-truck fleet’s diesel downtime by 35% in a year.
See more CRANETEC results
Browse real equipment repair and fleet maintenance case studies.
View Case StudiesCustomer Testimonials
What Fleet Customers Say
“CRANETEC diagnosed a derate nobody else could find and fixed it fast. Our tractor is back making runs on time.”
Marcus R.
Fleet Manager · Regional Logistics Co.
“When my truck started smoking and losing power, they found the bad injectors and had me back on the road in two days.”
Dana T.
Owner-Operator · Independent Hauler
“Their diesel maintenance program keeps our vocational trucks running. Far fewer breakdowns and the records make audits easy.”
Greg H.
Operations Manager · Southeast Construction
“Mobile diesel service comes to our yard, so our trucks stay on route. Reliable, responsive, and professional every time.”
Pamela L.
Fleet Supervisor · Municipal Public Works
“DPF and DEF warnings were derating our trucks. CRANETEC cleaned the system and cleared everything — no more limp mode.”
Carlos M.
Utility Contractor · Fiber & Telecom
Service Areas
Diesel Repair Where You Operate
Mobile service and shop support across our regions. Call to confirm coverage for your location.
Related Services & Resources
Explore the Heavy-Duty Truck Repair Cluster
Heavy Duty Diesel Repair FAQ
Direct answers to the most common commercial diesel repair questions.
Heavy duty diesel repair is the professional service and maintenance of commercial diesel engines and the vehicles that rely on them — Class 5 through Class 8 trucks, semi tractors, vocational trucks, and heavy equipment. It covers computerized diagnostics, engine repair and overhaul, turbocharger and fuel system service, cooling system repair, electrical diagnostics, emissions aftertreatment, and preventive maintenance. CRANETEC performs heavy duty diesel repair for commercial fleets, owner-operators, municipalities, and contractor fleets with a focus on long-term reliability rather than temporary fixes.
Need Heavy Duty Diesel Engine Repair?
Fast diagnostics, dependable repairs, and clear communication — get your truck back to work. For immediate service, call now.
Request Diesel Service
Fast response · OEM-level diagnostics · Fleet scheduling