Diesel Engine Specialists · 26 Years Experience · (803) 329-9755

Diesel Engine Repair

The engine is the heart of your commercial truck. When it needs repair — whether it's a targeted fix on a specific system or a full engine overhaul — you need a shop that knows diesel engines from the inside out. Interstate Fleet Services has been repairing commercial diesel engines in Rock Hill, SC for 26 years. We work on all major engine platforms: Cummins, Detroit Diesel, PACCAR, Volvo, Mack, and Caterpillar. No job too big — A to Z coverage includes full engine overhauls.

We start with accurate diagnosis. A diesel engine repair that addresses the symptom instead of the root cause is money wasted. Our diagnostic process identifies what failed, why it failed, and what needs to be done to prevent the same failure from recurring.

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Engine Repair Services

In-Frame Engine Overhaul

Complete cylinder rebuild with pistons, rings, liners, bearings, gaskets, and seals replaced with the engine in chassis. Most efficient approach for standard overhauls on healthy blocks.

Out-of-Frame Engine Overhaul

Engine removal for comprehensive rebuild allowing full block inspection, crack testing, and component evaluation. Recommended when engine has significant wear or damage history.

Fuel System Repair

Common-rail injection system service: injector testing, replacement, high-pressure pump service, fuel rail inspection. Contaminated fuel system flush and component replacement.

Turbocharger Repair & Replacement

Turbo diagnosis, oil system root-cause analysis, and turbo replacement. We identify why the turbo failed and address the underlying cause so the replacement lasts.

Cooling System Overhaul

Thermostat, water pump, cooling hoses, radiator, and head gasket service. Overheating is a fast path to catastrophic engine damage — we fix cooling systems right.

EGR & Emissions System

EGR valve, EGR cooler, DPF, DOC, and SCR system repair. Emissions components require proper service to maintain fuel economy and avoid derating faults.

Valve Train Service

Valve lash adjustment, rocker arm inspection, cam follower service, and valve cover gaskets. Valve train issues are common on high-mileage engines.

Engine Rebuild Kits

We source quality in-frame and out-of-frame rebuild kits from reputable suppliers for all major engine platforms. We discuss OE, remanufactured, and aftermarket options.

Engine Repair FAQ

What diesel engine brands do you repair?

We work on Cummins (ISX, X15, ISB, ISC), Detroit Diesel (DD13, DD15, DD16, Series 60), PACCAR MX-11 and MX-13, Volvo D11/D13, Mack MP8/MP10, Navistar MaxxForce, and Caterpillar C-series truck engines. Both older mechanical engines and fully electronic modern platforms.

What's the difference between an in-frame and out-of-frame overhaul?

An in-frame overhaul rebuilds the engine with the block remaining in the truck — pistons, rings, liner, bearings, and gaskets are replaced with the engine in place. An out-of-frame overhaul removes the engine for a more comprehensive rebuild. We assess and recommend based on the engine's condition and the scope of failure.

How do I know if my engine needs an overhaul vs a repair?

Key indicators for overhaul consideration: excessive oil consumption, blow-by at the crankcase breather, low compression on cylinder contribution tests, worn bearings indicated by oil analysis, or a high-mileage engine with declining performance. Targeted repairs address specific failures without full overhaul. We diagnose and give an honest recommendation.

Do you work on older mechanical diesel engines?

Yes. We work on older mechanical injection engines — Cummins NTC/N14, Detroit Series 60, CAT 3406E — as well as modern electronic engines. Older mechanical engines often have more straightforward repairs when problems are identified.

How long does an engine overhaul take?

An in-frame overhaul typically takes 3–7 days depending on parts availability and the scope of work. Out-of-frame overhauls can take 1–2 weeks. We give you a realistic timeline before starting and communicate if anything changes.

Engine Problem? Call Interstate Fleet.

26 years of diesel engine expertise. All major platforms. Rock Hill, SC.

(803) 329-9755
Emergency: (803) 329-9755