2007 Newmar Mountain Aire 4521 45 Luxury Diesel Pusher Excellent Condition

This beautifully maintained 2007 Newmar Mountain Aire 4521 is a high end, 45-foot Class A diesel pusher built on the Spartan K2 chassis and powered by the legendary 450 HP Cummins ISM paired with 6 speed Allison automatic transmission. If you're looking for a powerful, reliable and exceptionally well cared for coach, this one stands out.

Coach Highlights

• 92,300 miles

• Pre-DEF

• Never been smoked in and no pets - very clean interior

• Spartan K2 chassis

• 450 HP Cummins ISM engine

• Allison 6 speed automatic transmission

• 15,000 lb towing capacity

• Four power slide-outs

• Aqua Hot hydronic heat and endless hot water (electric + diesel)

Generator & Power

• Oran 10kW diesel generator 1,700 hours

• Provides reliable power for boondocking and travel

• Front tire codes: 4124

• All other tires replaced on 2/23/2026 - Tire codes: 2525

• House batteries replaced on 2/16/2026

• These upgrades alone save the next owner thousands of dollars

Interior Comfort

• Spacious quad slide layout

• Quality Newmar craftsmanship throughout

• Clean, odor free interior

• Comfortable living area, fully equipped kitchen, and well-designed bedroom suite

Why This Mountain Aire is a Great Buy

This coach combines top tier build quality, a highly desirable powertrain, and a long list of recent maintenance updates. The indoor storage, no smoke/no pet history, and mechanical care is far above average for its age. If you're searching for a well-maintained Mountain Aire 4521 ready for cross country travel, this one deserves your attention.