2009 Monaco Signature Fortress IV Class A Diesel Motorhome
One Owner | Cummins ISX 650 | Less Than 500 Miles on Replacement Engine | Extensive Upgrades | Complete Service History
This 2009 Monaco Signature Fortress IV is an exceptional one-owner luxury diesel motorhome with a complete service history from new and extensive recent mechanical upgrades.
Most notably, Cummins installed a replacement ISX 650 HP diesel engine in 2023, and the engine has less than 500 miles on it. The coach has also received major chassis, drivetrain, electrical, and suspension updates, making it an outstanding example of Monaco’s flagship Signature line.
Major Mechanical Upgrades
The owner has invested heavily in keeping this coach mechanically current and road-ready.
Recent work and upgrades include:
- Cummins-built ISX 650 HP replacement engine installed in 2023
- Less than 500 miles on the replacement engine
- Transmission rebuilt in 2020
- All airbags and shocks replaced in 2022
- Complete coolant hose replacement in 2023, including generator hoses
- Radiator flushed and coolant pump rebuilt
- Engine bay hoses and connections inspected prior to engine installation
- Magnum inverter replaced in 2023
- Battle Born lithium-ion house batteries installed in 2023
- Steering stabilizer system
- Dual air and hydraulic leveling systems
- Brand-new spare drive shaft stored onboard
The replacement Cummins engine was originally covered by warranty through October 2025.
Complete One-Owner Service History
This Monaco has been owned by the same owner since new and comes with comprehensive maintenance and service records.
The detailed history provides valuable insight into the coach’s care, repairs, and upgrades over the years, with records available for review.
Luxury Monaco Signature Interior
Inside, the Signature delivers the high-end craftsmanship and residential comfort Monaco was known for.
Interior highlights include:
- Handcrafted polished wood cabinetry
- Premium leather seating
- Residential refrigerator
- Convection microwave
- Induction cooktop
- Dishwasher
- King-size bed
- Washer/dryer
- Heated residential-style flooring
- Elegant bath and shower area
- Multiple flat-screen televisions
- Bose surround sound system
Both the driver and passenger ride in premium Knoedler air-cushion captain’s chairs featuring heat, air conditioning, and massage functions.
Technology & Exterior Upgrades
This coach has also received several valuable custom upgrades designed to improve visibility, convenience, and long-distance travel.
Features include:
- Custom four-camera exterior camera system with large-screen monitor
- Navigation system
- Wi-Fi extender
- Keyless entry
- Full front cap protected by Paint Protection Film
- Power-operated storage bay slides
- Newly carpeted storage compartments
- LED rope lighting around the entire underside perimeter
- 30-amp outlet in storage bay for stacker trailer use
- Tow hitch with air line for trailer braking system
- Separate rear driver-side hitch for flagpole
Power, Water & Comfort Systems
The coach is equipped for extended travel and comfortable year-round use with:
- Onan 12.5kW diesel generator
- Oasis hydronic heating and hot water system
- Custom reverse osmosis water filtration system
- Dual-zone climate control
- 150-gallon diesel fuel tank
- 100-gallon fresh water capacity
Why This Monaco Signature Stands Out
It is increasingly difficult to find a flagship luxury diesel coach with this combination of one-owner history, complete service documentation, and extensive recent mechanical investment.
With its 650 HP replacement Cummins engine, rebuilt transmission, updated suspension, lithium battery system, premium interior, and numerous custom upgrades, this Monaco Signature Fortress IV offers tremendous value for a buyer looking for a high-end diesel motorhome that has been exceptionally well cared for.
Contact Cassones RV today to schedule a private showing and see this remarkable 2009 Monaco Signature Fortress IV in person.