863709A02 Aftermarket Mercruiser 4.3L/5.0L/5.7L/6.2L Heat Exchanger | Sawley's Select Marine Parts

🔧 Product Description

Aftermarket Mercruiser 4.3L/5.0L/5.7L/6.2L Heat Exchanger - Replacement Part Number: 863709A02

Complete heat exchanger in the later 863709 service chain.

⚙️ Key Features

• Marine-grade shell-and-tube heat exchanger

• Designed as a direct replacement for the listed reference numbers

• Helps maintain stable operating temperature under sustained marine load

• Marine connection sizes and mounting points must match the original assembly

• Suitable for professional marine cooling-system service and replacement

🔄 Supersession & Cross Reference

OEM Supersession Chain:

• 863709A02 → Supersedes 863709A1 and 863709

OEM / Related Numbers:

• 863709A02

• 863709A1

• 863709

• 22-806608A01 plug

Aftermarket / Verified Equivalents:

• Seakamp: 863709A02 replacement

• Mr Cool: MRC863709A02

• Lenco: 863709A02 replacement

🚤 Compatibility

Commonly used on:

• Marine-grade shell-and-tube heat exchanger systems

Typically suits:

• Engine models:

• MerCruiser 4.3L V6

• MerCruiser 5.0L and 5.7L V8

• MerCruiser 6.2L V8

• Engine Type: GM V6/V8 petrol marine engine

• Plug 22-806608A01 is not included unless stated

• Reuse the original small top-right disc where required

🔌 Function

The heat exchanger keeps closed-loop coolant separate from seawater while transferring heat through the tube stack.

Common signs of failure:

• Engine or generator temperature rises above normal under load

• Coolant loss or seawater leakage around the exchanger

• Restricted seawater flow from scale, debris or damaged tubes

• Coolant contamination caused by an internal tube failure

• Corroded end covers, tube stack or sacrificial anode

📦 Condition

• Brand new aftermarket replacement part

• New and unused

• Supplied in manufacturer or equivalent protective packaging