GCS Aftermarket Cummins C5.9 Stainless Steel Exhaust Mixer Gasket 3921961 | Sawley's Select Marine Parts

🔧 Product Description

Aftermarket Cummins C5.9 Stainless Steel Exhaust Mixer Gasket 3921961 - Part Number: GCS

A stainless-steel crush gasket for the Cummins marine exhaust-mixer flange. It replaces Cummins 3921961 and seals the joint between the turbo-side exhaust flange and the mixing-elbow assembly.

⚙️ Key Features

• Stainless-steel crush construction

• Direct replacement for Cummins 3921961

• Designed for high-temperature turbo-exhaust service

• Compatible with the HDI C5.9 and CUMA systems

• Replace whenever the exhaust joint is dismantled

🔄 Supersession & Cross Reference

OEM Supersession Chain:

• HDI GCS → Replaces Cummins 3921961

OEM / Related Numbers:

• HDI GCS

• Cummins 3921961

Aftermarket / Verified Equivalents:

• HDI Marine: GCS

🚤 Compatibility

Commonly used on:

• Cummins marine turbocharger and mixing-elbow joints

Typically suits:

• Engine models:

• Cummins 6BT5.9

• Cummins 4BTA

• Cummins 6BTA5.9

• Cummins QSB5.9

• Cummins 6CTA8.3

• Cummins QSC8.3

• Cummins QSB6.7

• Cummins QSB6.9

• Cummins QSL9

• Material: stainless-steel crush gasket

• Joint Type: turbocharger / exhaust-mixer flange

🔌 Function

The gasket conforms between the two exhaust flanges to prevent hot exhaust gas escaping and to stop moisture reaching the turbocharger joint.

Common signs of failure:

• Black soot tracking around the joint

• Cooling-water seepage or salt deposits at the flange

• Exhaust smell or fumes in the engine compartment

• Burnt, split, crushed or hardened sealing material

• Corrosion or erosion of the mating faces

📦 Condition

• Brand new aftermarket replacement part

• New and unused

• Supplied in manufacturer or equivalent protective packaging