How Saltwater Affects Your Diesel Engine in the Puget Sound

Puget Sound is one of the most unique marine environments in the United States. Its mix of cold saltwater, fluctuating salinity, marine debris, and high biological activity creates ideal conditions for corrosion and engine wear. Boaters who run in saltwater, or even occasionally leave marinas for the Sound, must understand the risks to their diesel engines.

How Saltwater Causes Corrosion

Saltwater accelerates electrochemical reactions on metal components, especially when engines cycle between hot and cold. Corrosion affects:

• Heat exchangers

• Exhaust elbows

• Raw water pumps

• Zinc anodes

• Cooling system fittings

• Transmission coolers

Even boats used in Lake Washington or Lake Union occasionally are affected when they spend time in Puget Sound.

Mineral Buildup and Scaling

Saltwater minerals accumulate inside cooling systems. Over time, scaling reduces heat-transfer efficiency, causing overheating. Heat exchangers and coolers must be cleaned or descaled regularly to prevent flow restriction.

Raw Water System Wear

Raw water pumps constantly pull in abrasive particles from Puget Sound. Sand, shell fragments, and marine debris damage:

• Pump housings

• Impellers

• Seals and bearings

Pump failure is one of the leading causes of overheating in Seattle's waterways.

Electrical System Damage

Salt air is highly conductive and corrosive. Electrical failures often begin with:

• Oxidized terminals

• Green or white corrosion on connectors

• Voltage drops

• Alternator output issues

• Poor grounding

Boats kept in saltwater marinas must have regular electrical inspections.

Exhaust Elbow Failure

Exhaust elbows mix raw water with exhaust gases. Saltwater accelerates internal corrosion, often out of sight. A failing elbow causes:

• Overheating

• SmokeLoss of power

• Water intrusion into cylinders

Elbows must be inspected every 2–3 years in Puget Sound.

Prevention

• Annual raw water service

• Heat exchanger cleaning

• Zinc replacement

• Freshwater flushing when possible

• Engine descaling

Schedule a diagnostic inspection with Nautix Marine

Protect your diesel from Puget Sound’s saltwater. Contact Nautix Marine for a comprehensive saltwater protection inspection.

Call or text us to schedule a diagnostic inspection with Nautix Marine today.