Product Description
Interstate-McBee M-3938655 Vacuum Pump Gasket – 1989–1993 5.9L Cummins 12-Valve
Direct-fit gasket that seals the vacuum pump to the timing gear housing on 1989–1993 Dodge Ram 2500/3500 with the 5.9L Cummins 12-valve (6BT). Ideal for pump service, leak repair, or front cover work. Sold individually.
- Leak stop: Restores a proper seal to help prevent oil seepage around the vacuum pump interface.
- OE-style fit: Designed to the same footprint and bolt pattern as the factory gasket.
- Service friendly: Replace any time the vacuum pump is removed.
Specifications
| Brand | Interstate-McBee |
| Part Number | M-3938655 |
| OEM Reference | Cummins 3938655 |
| Location | Vacuum pump to timing gear housing |
| Sold As | Each (1 gasket) |
What’s Included
- (1) Vacuum pump mounting gasket, P/N M-3938655
Vehicle Fitment
Verify by engine serial number (ESN) when possible.
- Dodge Ram 2500/3500 with 5.9L Cummins 12-valve (6BT)
- Model Years: 1989–1993
Install Notes
- Clean both mating surfaces until free of old gasket material and oil.
- Install gasket dry unless otherwise specified by the service manual.
- Apply thread sealant only where factory procedure calls for it.
- Torque fasteners to Cummins spec and tighten evenly in a cross pattern.
- After start-up, check for leaks with the engine at operating temperature.
Recommended/Related Parts
- Vacuum pump O-rings / seal kit (if applicable to your pump)
- Front cover gasket set (if servicing the timing housing)
- Fresh hardware or washers if the originals are corroded
Why Buy From CPP Diesel
- Diesel-specialist support with ESN-verified fitment help
- Fast shipping and easy returns
- Competitive pricing on Interstate-McBee and Cummins service parts
FAQ
Do I need sealant with this gasket?
Typically no—install it dry unless your service manual specifies a sealant at certain points. Always follow Cummins procedures.
When should I replace this gasket?
Any time the vacuum pump is removed, or if you notice oil seepage at the pump-to-housing interface.
Does this fit 1994+ 12-valve or 24-valve engines?
This listing targets 1989–1993 12-valve applications. Later years may use different sealing parts; verify by ESN before ordering.
