Mercury – 15W-40 Heavy Duty Diesel Engine Oil | 858042K01

Overview

Marine diesel engines live a tougher life than most — long hours, heavy loads, and salt air that doesn’t forgive a thing. That is why Mercury 15W-40 Heavy Duty Diesel Engine Oil exists. It is made for boaters who understand that reliability isn’t optional. Every turn of the crank, every trip offshore, this oil is there — protecting, cooling, and cleaning. It’s the difference between worrying about your engine and trusting it completely.

Key Features

• Premium 15W-40 multi-grade diesel oil.
• Meets or exceeds API CH-4/CF-4/SJ standards.
• Protects against wear, soot buildup, and corrosion.
• Controls sludge and varnish for cleaner operation.
• Ideal for non-TDI Mercury/MerCruiser diesel engines.
• Supplied in a 1-gallon container.

Engine & Boat Compatibility

• Designed for Mercury and MerCruiser non-TDI diesel engines.
• Suitable for 3.0L V6 VM diesel applications.
• Compatible with Volvo VDS, Caterpillar CD/TO-2, Cummins, and Detroit Diesel systems.
• Works across fishing vessels, workboats, and cruisers.

Performance & Practical Benefits

Mercury’s Heavy Duty Diesel Oil doesn’t just protect — it preserves performance. It keeps your diesel running smooth and steady, even after long days at high RPMs. You’ll notice less soot, cleaner exhaust, and more consistent oil pressure. It prevents varnish and sludge from building up, keeping every moving part in sync.

Whether your boat’s used for work or leisure, this oil holds up under stress. It’s made to endure hot runs, cold starts, and everything in between. The protection is steady, predictable, and strong — the kind of quiet performance that gives you confidence on every trip.

Why Buy OEM

When you’re running a diesel on open water, cheap oil just isn’t worth the risk. This Mercury Marine part was built for your engine, tested to handle the harsh conditions marine diesels face daily. Using OEM oil means your investment stays protected — with cleaner operation, longer intervals, and reduced wear.

You can’t fake quality like this. Mercury’s engineers built this oil to match the exact chemistry your engine needs, so it fits, flows, and performs perfectly from day one.

FAQ Section

Q1: Which engines use Mercury 15W-40 Diesel Oil?

It’s made for Mercury/MerCruiser non-TDI diesel engines and compatible marine diesel applications.

Q2: What makes it different from fleet diesel oils?

This marine-specific blend resists corrosion and sludge caused by salt and humidity.

Q3: Can it be used in other diesel engines?

Yes, it meets API CH-4/CF-4/SJ standards for use in Volvo, Caterpillar, Cummins, and Detroit Diesel engines.

Q4: Does it protect in both hot and cold conditions?

Absolutely — the 15W-40 viscosity provides consistent flow and protection across temperatures.

Q5: Is it easy to use?

Yes, the 1-gallon size is convenient for oil changes and maintenance schedules.