4020101CN Aftermarket Cummins 5.9L/QSB Heat Exchanger 4 x 25 in | Sawley's Select Marine Parts

🔧 Product Description

Aftermarket replacement Engine Heat Exchanger - Replaces Part Number: 4020101CN

New copper-nickel heat exchanger replacing Cummins 4020101 on later 5.9L six-cylinder marine engines and specified QSB 6.7SL installations.

⚙️ Key Features

• Direct replacement for Cummins 4020101

• Approximately 4-inch diameter × 25.68-inch shell

• Copper-nickel seawater core

• Raw-water connections approximately 1.5 and 1.75 inches by installation

• Coolant connections approximately 1.75 and 2.375 inches

🧰 Kit / Assembly Contents

• 1 × Complete heat exchanger assembly - P/N 4020101CN

• 1 × sacrificial anode - replacement family CDZ9-036

• 1 × four-inch end-cover/gasket kit - MRC4884-1A, ordered separately unless included

• End-cover gasket-only service reference LP GAKHE4.0-3

🔄 Supersession & Cross Reference

OEM Supersession Chain:

• 4020101CN → Copper-nickel replacement for Cummins 4020101

OEM / Related Numbers:

• CDZ9-036

• MRC4884-1A

• GAKHE4.0-3

Aftermarket / Verified Equivalents:

• Mr Cool: MRC4020101CN

• Seakamp: 4020101CN

• Lenco: LE4020101

🚤 Compatibility

Commonly used on:

• Later Cummins B/QSB marine diesel engines

Typically suits:

• Engine / Equipment models:

• Late-style 6BTA 5.9

• Tier 3 ISB/QSB 5.9

• QSB 6.7SL installations specifying 4020101

• Output / Engine Rating: Engine rating is calibration-dependent

• Engine / System Type: Inline six-cylinder turbocharged common-rail marine diesel engine

• Year Range: Late 5.9L/QSB production; serial-dependent

• Serial / Model Identification: Confirm engine serial and the unequal raw-water/coolant hose diameters.

🔌 Function

The heat exchanger transfers engine or generator coolant heat into the raw-water circuit while keeping the two fluids separated. This maintains the correct closed-circuit operating temperature and protects the engine from direct seawater circulation.

Common signs of failure:

• Engine or generator overheating under sustained load

• Coolant loss without an obvious external hose leak

• Saltwater and coolant cross-contamination

• Restricted raw-water discharge or uneven end-cap temperature

• Corrosion, green staining, cracked solder joints or pressure-test failure

📦 Condition

• New aftermarket replacement part

• Brand new

• Supplied in original or equivalent packaging