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Coolant System Repair

Heavy-Duty Diesel Cooling System Repair — Russellville KY

In short

Coolant failures are how engines die. A leaking water pump, a stuck thermostat, a clogged radiator, or a leaking EGR cooler can take a Cummins ISX or Detroit DD15 from running to scrap in one drive. We diagnose cooling-system failures, isolate the leak source, and fix it — usually at your yard. Coolant in the oil gets the engine out of service immediately until we figure out where it's coming from.

Call (931) 561-7736

Based in Russellville, KY · 75-mile radius

Symptoms we look for

You hear
  • · Coolant gurgling in the dash
  • · Hissing under the hood after shutdown
  • · Fan running hard at idle
You see
  • · Coolant level dropping
  • · Sweet-smelling steam from the hood
  • · Coolant in the engine oil (milky oil on the dipstick)
  • · Puddles under the truck
You smell
  • · Sweet ethylene glycol smell
  • · Burnt coolant on the exhaust

What we cover

  • Radiator repair and replacement
  • Water pump replacement (front and rear, depending on engine)
  • Thermostat replacement
  • Hose replacement (upper, lower, heater, charge-air-cooler lines)
  • Fan and fan clutch replacement
  • EGR cooler replacement (also covered under emissions)
  • Oil cooler replacement
  • Coolant flush, fill, and SCA / extended-life testing
  • Head gasket diagnosis (limited — see FAQ)

How we handle it

Step one is finding where the coolant is going. External leaks are easier — you see them. Internal leaks (coolant burning out the exhaust, coolant in the oil, coolant going somewhere you can't see) take more diagnosis. We pressure-test the system, look for the failure path, and identify which component is the culprit. Most cooling jobs are field-repairable. Head gasket diagnosis we can confirm on-site (pressure test, combustion-gas check in the coolant) but the repair is typically a shop job unless it's a Cummins ISX with a specific OEM service procedure that works in-frame.

Parts & warranty

Radiators OEM or quality aftermarket (Modine, Spectra Premium). Water pumps OEM. Thermostats OEM. Hoses Gates or Goodyear silicone for high-heat applications. Coolant in the engine maker's spec — ELC for most modern engines. 1-year parts-and-labor warranty.

Related services

Other repairs

Coverage by city

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

Need coolant system repair? Call Brennan.

On-site diesel and semi truck repair across the I-65 / I-24 corridor. 24/7 dispatch — the owner answers.

Call (931) 561-7736

Real work, real shop

  • Engine bay with intake plumbing and alternator visible
  • Engine bay during top-end service work
  • Engine head with the valve cover removed

Frequently asked

My truck is losing coolant but I can't find a leak. What's going on?
Three usual suspects: an EGR cooler with an internal leak, a head gasket starting to fail, or an oil cooler with a coolant-side leak into the oil. Pressure-test plus combustion-gas test in the coolant tells us which it is.
How much does a water pump cost on a Cummins ISX?
Parts plus labor lands around $700–$1,200 depending on where the water pump is in the engine generation and cab access. We give a firm number after we confirm it's the actual leak source.
Can you flush the cooling system in the field?
Yes. We carry the equipment to do a proper drain, flush, and refill with the correct coolant spec. Cooling-system flush is usually paired with a thermostat or water-pump job — there's no point putting old coolant back over a new water pump.
My EGR cooler is leaking — do I have to replace it?
Yes if the leak is into the intake (you'll see coolant loss without external leakage and white-ish smoke under load). EGR cooler failure is a high-frequency failure mode on modern emissions-equipped engines.

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

Call (931) 561-7736