Product Description
The CUMMINS 3900687 OEM REAR CAM EXPANSION PLUG is designed for 1989–2002 5.9L Cummins diesel engines. This genuine Cummins expansion plug seals the rear camshaft bore in the engine block, helping maintain proper oil containment and preventing leaks from the rear of the engine.
Use this part during engine rebuilds, camshaft replacement, rear engine service, or whenever the factory expansion plug shows signs of damage, corrosion, or leakage. Always verify fitment by engine serial number before ordering.
FEATURES
- Genuine Cummins OEM rear cam expansion plug
- Direct-fit replacement for factory-installed plug
- Helps prevent oil leaks from the rear cam bore
- Designed to meet original Cummins specifications
- Ideal for engine rebuilds and major service work
FITMENT
- 1989–1998 Dodge Ram 2500/3500 5.9L Cummins 12-Valve
- 1998.5–2002 Dodge Ram 2500/3500 5.9L Cummins 24-Valve
- Select Cummins 5.9L B-Series industrial and commercial applications
WHAT'S INCLUDED
- 1 Cummins 3900687 OEM Rear Cam Expansion Plug
CROSS-REFERENCE AND RELATED PRODUCTS
- Cummins 3900687
- Cummins Camshaft Components
- Cummins Front Cover Seals
- Cummins Rear Main Seal Components
SPECIFICATIONS
- Manufacturer: Cummins
- Part Number: 3900687
- Part Type: Rear Cam Expansion Plug
- Engine Compatibility: 5.9L Cummins 12-Valve, 5.9L Cummins 24-Valve
- Fitment Years: 1989–2002
- Vehicle Application: Dodge Ram 2500 and 3500
- Condition: New OEM Cummins
- Location: Rear Camshaft Bore
- Installation Type: Direct Replacement
FAQ
Will this rear cam expansion plug fit my truck?
This plug fits many 1989–2002 5.9L Cummins applications. Always verify fitment by engine serial number before ordering.
What does the rear cam expansion plug do?
The rear cam expansion plug seals the rear camshaft bore in the engine block to help prevent oil leakage and maintain proper engine sealing.
Is this a genuine Cummins part?
Yes. Cummins 3900687 is a genuine OEM Cummins replacement component.
When should this plug be replaced?
Replacement is recommended during engine rebuilds, camshaft service, or whenever leakage, corrosion, or damage is found.
What is included?
This listing includes one Cummins 3900687 OEM rear cam expansion plug.
Do I need any related parts?
Inspect rear main seal components, camshaft components, engine block plugs, and other sealing surfaces during service and replace worn parts as needed.
