Product Description
Interstate-McBee M-3678603 Turbo Oil Inlet O-Ring – 2007.5–2018 6.7L Cummins
Replacement turbocharger oil inlet O-ring for the 6.7L Cummins (2007.5–2018). Seals the oil feed at the turbo to prevent leaks and pressure loss. Sold individually.
- Direct replacement: OE-style seal for factory turbo oil feed inlet.
- Reliable sealing: Proper crush and elasticity for hot oil service.
- Maintenance friendly: Ideal to replace any time the turbo or feed line is serviced.
- Value: Interstate-McBee quality at an aftermarket price.
Specifications
| Brand | Interstate-McBee |
| Part Number | M-3678603 |
| OEM Reference | Cummins 3678603 |
| Location | Turbocharger oil feed (inlet) sealing ring |
| Sold As | Each (1 O-ring) |
What’s Included
- (1) Turbo oil inlet O-ring, P/N M-3678603
Vehicle Fitment
Always verify by engine serial number (ESN) when possible.
- Ram 2500/3500/4500/5500 with 6.7L Cummins diesel
- Model Years: 2007.5–2018
- Additional 6.7L Cummins B-Series applications using Cummins 3678603 (confirm by ESN).
Recommended/Related Parts
- Turbo oil feed line seals and gaskets
- Turbo oil drain tube gasket/O-ring
- Turbo mounting hardware (studs/nuts)
- Fresh engine oil and filter (after turbo service)
Install Notes
- Clean mating surfaces and lightly lubricate the new O-ring with fresh engine oil before installation.
- Do not twist, nick, or over-stretch the O-ring during assembly.
- Tighten fittings/fasteners to manufacturer torque specs and check for leaks after startup.
Why Buy From CPP Diesel
- Knowledgeable diesel specialists with ESN-verified fitment support
- Fast shipping, easy returns, competitive pricing
- Deep inventory of Cummins turbo & sealing components
FAQ
Is this the O-ring that seals the turbo oil feed into the turbo?
Yes. This ring seals the oil inlet at the turbocharger. If the feed line is removed, you should replace this O-ring.
How many do I need?
One per turbo oil inlet. Most trucks require a single O-ring.
Will it fit 2019+ 6.7L trucks?
This listing is for 2007.5–2018. Later models may use different seals—verify by ESN or parts catalog.
