Where is my coolant going if there's no leak on the ground?

It may be leaking internally — into the oil, the combustion chamber, or through an oil or EGR cooler. We test for combustion gas and check the oil.

Why does my equipment only overheat on dusty jobs?

Dust packs into the radiator and cooler fins, blocking airflow. Cleaning the cores properly, including between stacked coolers, often solves it.

Should I use any coolant I can find?

No. Mixing coolant types can cause problems. Use the type specified for the engine.

What does oil in the coolant mean?

Often an oil cooler failure, but a head gasket is also possible. The system needs a repair and a thorough flush.

Glendive, Montana

Cooling System Repair

Overheating does damage fast: warped heads, failed head gaskets and scuffed liners can all start with one hot pull up a grade. Mondak repairs cooling systems on trucks and equipment — radiators, charge air coolers, oil and hydraulic coolers, thermostats, water pumps, fans, fan clutches and fan drives, hoses and caps. We pressure-test the system, check coolant condition and look for contamination such as oil or combustion gas in the coolant. On equipment working in dust, chaff or coal, plugged cooler cores are one of the most common causes of overheating we see.

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Repair

WHAT WE SERVICE

Work tied to the actual fault.

Cooling system pressure testing and cap testing
Radiator, charge air cooler and cooler stack service
Thermostat and water pump replacement
Fan clutch, viscous drive and hydraulic fan drive diagnosis
Coolant condition, freeze point and additive testing
Flushing after oil or combustion contamination
Hose, clamp and coolant pipe replacement

COMMON NEEDS

Temperature climbing under load or on grades
Coolant disappearing with no puddle
Fan not engaging, or running all the time
Oily film or sludge in the coolant
Bubbles in the overflow tank
Loader or excavator overheating in dusty work

THE MONDAK APPROACH

Diagnose first. Repair with purpose.

Overheating has three possible sources: not enough coolant flow, not enough airflow, or too much heat going in. We pressure test for leaks, verify thermostat and water pump operation, confirm the fan engages when commanded, and inspect cooler cores for plugging. Coolant loss with no visible leak gets checked for combustion gas, which points to a head gasket, cracked head or cooler failure.

Hoses, fan belts, and cooler cleaning can often be done in the field. Radiator replacement, water pumps and contamination flushing are more practical at the Glendive shop.

RELEVANT EQUIPMENT & BRANDS

CumminsCaterpillarDetroitJohn DeereTractorsLoadersExcavators

Brand references indicate service familiarity, not authorized dealer or factory status.

COMMON QUESTIONS

Questions about cooling system repair

Engine Repair, Rebuild & Overhaul Construction Equipment Repair Truck A/C & HVAC Repair Class A Motorhome & Diesel Pusher Repair Fluids & Lubricants

GLENDIVE, MONTANA

Tell us what’s down.

Share the unit, location and symptoms. We’ll help determine the practical next step.

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