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Genuine Mopar 68436631AA Fuel Water Separator Filter (MO-631) | OEM for Ram 6.7L Cummins & 3.0L EcoDiesel
Description
One filter, two elite engines, zero room for error. Whether you're hauling heavy with a 2019+ Ram 6.7L Cummins or running trails in a 3.0L EcoDiesel Jeep, your fuel system demands absolute purity. The Genuine Mopar 68436631AA (MO-631) is the factory-specified frame-mounted separator engineered to stop water and debris before they reach your high-pressure injectors.
Technical Significance
Modern diesel systems operate at pressures exceeding 30,000 PSI — at those levels, a single drop of water can cause tip-blowout in an injector. The MO-631 is built with proprietary media that specifically targets the emulsified water budget aftermarket filters routinely miss. This OEM kit isn't just maintenance; it protects your engine's warranty and its long-term reliability.
OEM vs. Aftermarket Comparison
| Feature | Genuine Mopar 68436631AA (This Product) | Generic Aftermarket Filters |
|---|---|---|
| Media Technology | OEM high-capacity synthetic | Standard low-grade cellulose (paper) |
| Water Separation | Optimized for 2019+ high-flow pumps | Prone to bypass under high pressure |
| Seal Precision | Factory-measured O-ring thickness | Risk of air-in-fuel from poor seals |
| Cold Performance | Anti-gel properties built into media | Higher risk of fuel starvation in winter |
Package Contents
- (1) Genuine Mopar fuel water separator filter (P/N 68436631AA / MO-631)
- (1) Factory-spec sealing O-ring
- Mopar official protective packaging
Vehicle Compatibility
The frame-mounted (rear) fuel filter for 2019+ heavy-duty trucks and 2020+ EcoDiesel models:
- Ram 2500/3500/4500/5500: 2019, 2020, 2021, 2022, 2023, 2024+ (6.7L Cummins)
- Ram 1500: 2020, 2021, 2022, 2023 (3.0L EcoDiesel)
- Jeep Wrangler JL: 2020, 2021, 2022, 2023 (3.0L EcoDiesel)
- Jeep Gladiator JT: 2021, 2022, 2023 (3.0L EcoDiesel)
Interchange / Cross-Reference: MO-631, 68436631AB.
Service Indicators
- "Water in Fuel" dashboard warning active
- Fuel starvation — the engine stutters under heavy acceleration or towing
- Milestone service: 15,000 miles (standard) or 10,000 miles (severe duty)
- Rough idle — inconsistent RPM at stoplights after a recent fill-up
Not sure it fits? Send us your VIN or Engine Serial Number (ESN) and we'll confirm 100% compatibility before you buy. Brand new, factory-sealed, and shipped fast.
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Customer Reviews
5.0 / 5
★★★★★
Based on 1 review
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★★★★★ Works great on my EcoDiesel Wrangler too
Bought this for my 2022 Jeep Wrangler JL 3.0L EcoDiesel. Same filter as the heavy Ram trucks — genuine Mopar MO-631. Seats perfectly in the housing, new O-ring included, no leaks. Water-in-fuel light has never come on since I started using OEM-only filters. Great that one part covers both my Wrangler and my brother's 2020 Ram 1500.
Frequently asked questions
How do I know this part fits my vehicle?
Every listing includes a full compatibility list by make, model, year, and engine. If you're unsure, send us your VIN or Engine Serial Number (ESN) via the chat or contact page and we'll confirm fitment before you order.
Are these genuine OEM parts or aftermarket alternatives?
Every product we sell is 100% genuine OEM — factory-sealed and sourced directly from the manufacturer or authorized distributors. We do not sell aftermarket substitutes or white-box alternatives.
Do I need a professional to install these parts?
Most fuel filters and basic maintenance components are straightforward DIY installs with basic hand tools. We recommend consulting your vehicle's service manual for torque specs and bleed procedures. For ignition components and TPMS sensors, a relearn procedure may be required — see the product description for details.