Diagnosing An Overheating Sealine SC42 Engine in Devon

Challenge

Diagnostics

• Full inspection and isolation of leaking components on both engines.
• Assessment revealed leaking seawater pumps, heat exchangers, and aftercoolers, with corrosion and collapsed shaft bearings as contributing factors.

Solution

• Disassembly

  Removed auxiliary belts, power steering pump, seawater pumps, connecting pipes, electrical cables, and starter motor from both engines. Coolant drained.

• Removal

  Heat exchangers, oil coolers, and aftercoolers taken off both engines for workshop servicing.

• Cleaning and Preparation

  Both engine blocks cleaned, corrosion treated with Fertan rust convertor, primed, and repainted in Volvo Penta green.

• Seawater Pumps

  Stripped, inspected, and rebuilt with genuine Volvo Penta shaft, wear, and impeller kits. Shot blasted and repainted.

• Aftercoolers

  Disassembled with heat and ultrasonics to prevent damage. Cores replaced as required, new genuine Volvo Penta parts fitted.

• Heat Exchanger/Oil Coolers

  Cleaned, rebuilt, and sealed with genuine Volvo Penta components.

• Reassembly

  All serviced assemblies refitted per workshop manual, with new gaskets, sealants, and pressure-tested for leaks. New coolant added.

• Annual Service

  Included pre-fuel filters, clear bowls for fuel condition, full diagnostics, updated EVC software, and cleaning of bilges.

• Pre-Checks and Testing

  Levels rechecked, engines run up on berth, followed by sea trial for confirmation. Corrosion guard applied to all components.

• Extra Comments

  Severe corrosion on pump and cooler components, requiring advanced cleaning and careful extraction to avoid further damage. Starboard aftercooler core required full replacement due to salt damage.