Engine Repair

Heavy-Duty Diesel Engine Repair — Cummins, Detroit, Paccar, Mack, Cat

Call (931) 561-7736 Request service

Based in Russellville, KY · 75-mile radius

Symptoms we look for

You hear

· Knock, ping, or rattle under load
· Turbo whistle that wasn't there before
· Misfire at idle

You see

· Oil pressure low
· Coolant in the oil (milky dipstick)
· Excessive blow-by from the breather
· Black, blue, or white smoke under load

You smell

· Burnt oil
· Coolant in the exhaust (sweet smell)
· Raw fuel from a stuck injector

What we cover

Injector replacement (single or full set)
Turbocharger replacement, including VGT actuator service
Head gasket replacement (in-frame when the OEM allows)
Water pump replacement
Oil cooler replacement
EGR cooler replacement
Front and rear main seal service
Valve adjustment (set the lash to OEM spec)
Air compressor replacement
Engine harness and sensor circuit repair

How we handle it

Engine repair starts with the right diagnosis. We pull the codes, look at the fuel and air data, do a manual compression check or cylinder cutout test if needed, and isolate the failure cylinder or component. We tell you what we found, what it'll cost, and the parts wait. Most in-frame work happens at your yard — injectors, turbos, water pumps, oil coolers, head gaskets on engines that allow in-frame head removal. Bottom-end work (crank, rods, mains) we send to a shop with the alignment fixtures.

Parts & warranty

OEM parts where the engine maker spec demands it (head gaskets, injectors, head bolts). Quality aftermarket where it makes sense and you'd rather not pay OEM margin (water pumps, oil coolers, hoses). We label which is which on the invoice. 1-year parts-and-labor warranty.

Related services

Other repairs

Coverage by city

Engine Repair on-site in the cities below. Each link goes to the per-city page with localized response details.

Request service

Request engine repair

Tell us what's going on and we'll call you back. For roadside emergencies, the fastest path is to call (931) 561-7736.

Real work, real shop

Frequently asked

Can you do an in-frame on a Cummins ISX?

Head removal and head gasket replacement — yes, the ISX has a service procedure for it. Full in-frame overhaul (liners, pistons, rod bearings) is allowed by Cummins but the parts and the cleanliness requirements make it more practical as a shop job.

How long does an injector replacement take per cylinder?

Most engines, an injector swap is 1–2 hours per cylinder including the recalibration into the scan tool. A full set on a 6-cylinder is typically a one-day job at your yard.

My turbo is whistling — does it have to be replaced?

Not always. A whistle can be a hose-clamp loose at the boot, a charge-air-cooler leak, or a turbo with a worn shaft. We test boost pressure and look at the turbo end-play before we replace. If the shaft has play, the turbo goes.

How much does a head gasket on a DD15 cost?

In-frame head gasket replacement on a DD15 is roughly $4,500–$6,500 parts and labor depending on what else needs done while the head is off. We give a firm number after we confirm the diagnosis.

What customers say

4.7 / 5 from 43 Google reviews

“Brennan was great — absolutely hire this guy. I own a local tree company in Goodlettsville and one of my work trucks broke down at short notice. He was able to get there within a day or two and diagnose it. My turbo went out on one of my vehicles — when I went to the dealership they told me the wait time was forever and the process would include taking the cab off, which wouldn't work well with my current setup. Within one day he was able to replace my turbo and get it running so I could get back in business. The job was really labor-intensive but he made quick work of it and it runs even better than it did before. He's now the main guy I go to.”

— Tyler M.
“We've used Blacktop Mobile Repair twice this month, and both experiences have been nothing short of amazing. They run a top-notch operation, and it really shows in the quality of service and professionalism they provide. Jacob, the service tech, went above and beyond to make sure our truck was taken care of. He even drove out of his way to make sure he had the exact part needed to fix the truck and get us back on the road quickly. That level of dedication and commitment is hard to find. As a trucking company, downtime is costly, and having a team like Brennan and Jacob we can rely on makes all the difference.”

— Matthew P.
“I've used these guys in the past for an air compressor installation. Jacob was great. And recently my alternator quit on the weekend. I called Jacob on a Saturday and he helped me find one that I could pick up myself. Both times Jacob was knowledgeable & fair. A few months later — again on a Saturday — I wasn't even in their area and I called again to get troubleshooting advice. They are very good at diagnosing. Was able to pinpoint the trouble. Thanks again guys!”

— Dennis W.

Read all 43 reviews on Google