Systems
Heat exchanger cleaning, testing and repair
A marine heat exchanger transfers engine heat into raw sea water through a bundle of small tubes, and those tubes silt up with salt, scale and shed impeller debris. Once flow is restricted the engine overheats no matter how healthy it is. I remove, clean, pressure test and repair exchangers, aftercoolers and oil coolers.
The tubes are smaller than you think
The passages in a tube bundle are narrow enough that a single shed impeller blade or a season of scale meaningfully cuts flow. From the outside the exchanger looks fine. Inside, half the tubes can be blocked solid, which is exactly what shows up when a bundle is pulled and photographed.
What is included
- Removal and inspection of the tube bundle
- Chemical and mechanical cleaning of tubes and housing
- Ultrasonic cleaning where fouling warrants it
- Pressure testing for internal leaks
- End cap, gasket and O ring replacement
- Aftercooler and oil cooler service
- Zinc anode replacement
How it works
Pull and look
The bundle comes out and gets photographed. Fouling is measured by what is visible in the tube ends, not estimated from engine temperature.
Clean and test
Tubes cleaned through, housing cleared, then pressure tested so an internal leak is not discovered after reassembly.
Reassemble and verify
New gaskets and anodes, back together, then temperature confirmed under load.
Marine heat exchanger tube bundles restrict cooling flow as salt scale and shed impeller debris accumulate inside the tubes, and internal condition can only be confirmed by removing the bundle for inspection and pressure testing.
Related systems work
Marine Generator Service
Service, repair and load testing for marine generators, the system that keeps air conditioning and power alive at anchor.
Marine Transmission Service
Gearbox service, fluid analysis, coupling and alignment work on marine transmissions and drive systems.
Cooling System Service
Raw water and closed loop cooling service, flushing and repair, the system that causes most marine diesel overheats.
Heat Exchanger Service: common questions
How do I know if my heat exchanger needs cleaning?
A gradual rise in operating temperature is the usual first sign, particularly under load. If the raw water pump, impeller, strainer and thermostat all check out, the exchanger is the next place to look.
Can a heat exchanger be repaired or does it have to be replaced?
Many can be cleaned, re-tubed or repaired. Replacement is the answer when the housing itself has corroded through or tubes have failed beyond repair, and pressure testing is what settles the question.
What causes an oil cooler to leak into the oil?
Internal corrosion perforating the tubes, which lets coolant or raw water into the oil. It shows in fluid analysis and it needs immediate attention because it damages bearings.
Tell me what the engine is doing
Describe the symptom on the phone and most of the time the problem is narrowed before I arrive. Surveys are booked around your sea trial date.