Used Diesel Truck Buying Guide | Kash Diesel Sicklerville NJ

A used diesel truck can be a smart investment—powerful, long-lasting, and often more affordable than new models. But a bad buy can cost you thousands in surprise repairs. Diesel engines are tough, but they come with unique systems that need to be evaluated properly.

At Kash Diesel & Auto in Sicklerville, NJ, we’ve inspected and repaired hundreds of used diesel trucks from across New Jersey, Pennsylvania, and Delaware. Use this guide to avoid common pitfalls and make sure your next used diesel purchase is a solid one.

Why Diesel Trucks Are Popular for Used Buyers

Higher mileage lifespan: Many diesels can run 300k+ miles with proper care
Towing and payload capacity: Better torque for work use
Fuel economy (for size): More efficient under load vs gas
Engine longevity: Built with heavier components
Strong aftermarket support: Upgrades, tuning, and parts are widely available

That said, they must be properly maintained to live up to their potential.

Pre-Purchase Diesel Truck Checklist

Here’s what to inspect or ask about before buying any used diesel truck:

1. Engine Start-Up and Idle

Cold start test is critical
Look for rough idle, white or blue smoke, long crank times
Listen for knocking, ticking, or excessive vibration

2. Exhaust Smoke Type

White smoke: unburnt fuel or coolant
Black smoke: too much fuel, injector issues
Blue smoke: burning oil (worn seals or turbo)

3. Maintenance Records

Was the truck serviced regularly?
Any records of oil changes, fuel filter replacements, coolant flushes?
Ask about DEF and DPF system repairs if 2010+

4. Check for Tuners or Deleted Emissions Systems

Emissions deletes are illegal in NJ, PA, DE and can cost you big
Deleted EGR/DPF/DEF = failed inspections + warranty risk
Check for wiring changes, removed components, or installed tuners

5. Look for Leaks

Inspect under the engine and transmission for:
Oil leaks
Coolant leaks
Fuel system leaks
Transmission fluid seepage

6. Transmission Health

Slipping, jerky shifting, or delayed engagement = red flags
Ask when fluid was last changed
Look for signs of towing or hard use (aftermarket coolers, trailer brake wiring, worn hitch)

7. 4WD System Function

Test 4x4 engagement
Listen for noise in front differential
Check CV joints, U-joints, and front axle seals

8. Suspension and Steering

Excessive play in the steering wheel?
Sagging leaf springs or worn shocks?
Rusted mounts or cracked bushings?

9. Rust & Frame Condition

Rust on body panels is cosmetic—rust on the frame is structural
Check wheel wells, bed rails, cab mounts, and undercarriage
Tap on suspect areas with a hammer or screwdriver to test integrity

10. Run a Diagnostic Scan

At Kash Diesel, we recommend a full scan with a diesel-specific scan tool
Check for: EGR faults, injector balance codes, turbo actuator errors, glow plug codes

Specific Checks by Engine Type

Ford Powerstroke

6.0L: Look for signs of head gasket issues, stud upgrades, EGR coolers
6.4L: Check for cracked up-pipes, DPF issues
6.7L: Pay attention to turbo whine and NOx sensor codes

Dodge/Ram Cummins

5.9L: Solid, but look for injector blow-by
6.7L: Watch for turbo actuator problems, grid heater issues

GM Duramax

LB7: Injector issues common (2001–2004)
LLY/LBZ: Check EGR and glow plug systems
LMM: Pay attention to DPF service history

Questions to Ask the Seller

What type of work was the truck used for?
Did you use any tuners or make performance mods?
Has the emissions system been altered in any way?
Do you have receipts for maintenance?
Why are you selling the truck?
Has the engine or transmission been rebuilt?
Any recurring issues?

Why a Pre-Purchase Diesel Inspection Matters

You might save $300–400 today by skipping a pro inspection—but end up paying $3,000+ later on major engine, turbo, or injector repairs.

At Kash Diesel, we offer:

Full diesel-specific diagnostic scans
Compression and cylinder contribution testing
DEF/DPF system inspection
Fluid analysis
Frame and suspension inspections
Turbo and injector evaluation

All findings are documented with photos and estimates.

Common Mistakes When Buying Used Diesels

Skipping emissions questions (especially for 2010+ models)
Assuming high miles = bad: Maintenance is more important than mileage
Buying without a scan: Hidden codes won’t show on the dash
Focusing only on cosmetics: A clean body can hide a tired drivetrain
Ignoring signs of abuse: Lift kits, giant tires, broken hitches often = hard use

FAQs: Buying Used Diesel Trucks

Is high mileage always bad on a diesel truck?
No. A 250,000-mile truck with proper care can be better than a 100,000-mile one with spotty maintenance.

Can you fix a deleted emissions system?
In many cases, yes. But restoring compliance can cost thousands and still may not pass inspection.

How much does a pre-purchase diesel inspection cost?
At Kash Diesel, inspections start around $250 and vary based on vehicle type and depth of testing.

Should I avoid older diesels entirely?
Not necessarily. Some pre-2007 trucks are very reliable—but lack emissions systems required for commercial work.

Do you help with fleet truck purchases?
Yes. We inspect vehicles for contractors, municipalities, and logistics companies looking to expand or replace fleet assets.

Let Kash Diesel Inspect Your Next Used Truck

Before you hand over cash for that used diesel truck, let our team check it thoroughly. You’ll get peace of mind—or walk away with the knowledge to negotiate or move on.

< Older Post

Buying a Used Diesel Truck? Here’s What to Check Before You Buy