177525-04821 / 117524-04820 Aftermarket Yanmar 6LY3-STP KMH61A Oil Cooler | Sawley's Select Marine Parts

🔧 Product Description

Aftermarket replacement Transmission Oil Cooler - Replaces Part Number: 177525-04821

New copper-nickel transmission-oil cooler for Yanmar 6LY3-STP installations fitted with the KMH61A marine gearbox. It replaces/cross-references Yanmar 177525-04821 and 117524-04820.

⚙️ Key Features

• Direct replacement for the listed Yanmar transmission-cooler references

• Designed for the KMH61A gearbox oil circuit

• Copper-nickel seawater core

• Supports 6LY3-STP propulsion packages

• Original-style oil and seawater port layout

🧰 Kit / Assembly Contents

• 1 × Complete transmission-oil cooler - P/N 177525-04821

• 1 × Integrated copper-nickel tube bundle

• Gear-oil line seals, seawater hoses and mounting hardware are renewed separately

🔄 Supersession & Cross Reference

OEM Supersession Chain:

• 177525-04821 ↔ Cross-references 117524-04820

OEM / Related Numbers:

• 117524-04820

• 17752504821

• 11752404820

• KMH61A

Aftermarket / Verified Equivalents:

• Mr Cool: MRC177525-04821CN

• Lenco: LE177525-04821

• Seakamp copper-nickel KMH61A cooler replacement

🚤 Compatibility

Commonly used on:

• Yanmar propulsion packages with KMH61A marine transmission

Typically suits:

• Engine / Equipment models:

• 6LY3-STP with KMH61A gearbox

• Related 6LY3 installations only where the original parts list specifies 177525-04821 or 117524-04820

• Output / Engine Rating: Approximately 380HP principal engine application

• Engine / System Type: Inline six-cylinder turbocharged/intercooled diesel with hydraulic marine gearbox

• Year Range: 6LY3 production era

• Serial / Model Identification: Confirm engine serial, gearbox designation and oil-port orientation.

🔌 Function

The cooler transfers heat from transmission or reduction-gear oil into the raw-water circuit. Correct oil temperature protects clutches, bearings, seals and hydraulic control components.

Common signs of failure:

• High transmission or reduction-gear oil temperature

• Burnt, darkened or aerated gear oil

• Delayed engagement, slipping or abnormal gear noise when hot

• Water-contaminated or milky transmission oil

• External oil leakage, corrosion or failed pressure test

📦 Condition

• New aftermarket replacement part

• Brand new

• Supplied in original or equivalent packaging