2006 Monaco Coach Diplomat Problems
Owner-reported complaints filed with NHTSA, grouped by component
Data refreshed
What this page shows
Everything below is an owner-reported complaint submitted to NHTSA about the 2006 Monaco Coach Diplomat, grouped by the component NHTSA recorded on the report. These are not confirmed defects, and they are not recalls. NHTSA does not verify most reports before publishing them, and a category with more reports in it is not evidence that a part is defective.
Complaints are reports submitted by owners and drivers to NHTSA. They are not verified and do not establish that a defect exists.
Reports by component
Ranked by how many owner reports name each component category
- Engine360.0%
- Body & structure120.0%
- Fuel system120.0%
Percentages are of component mentions. A single complaint can name more than one component, so these do not sum to the total complaint count.
Each component in detail
What the reports in each category say, in the owners' own words
Engine
Reports naming the engine itself — including stalling, misfires, oil consumption, cooling and internal engine components.
From owner reports, verbatim
OWNER OF A 2006 40' MONACO DIPLOMAT RV MOTORHOME DELIVERED WITH A 400HP DIESEL ENGINE, MANUFACTURED BY CUMMINS INC. RECEIVED A RECALL NOTICE RE A POSSIBLE ENGINE FAILURE; HE IS REQUESTING HELP IN ORDERING CUMMINS TO INSTALL A PROPER MANUFACTURED ENGINE. *KB THE CONSUMER STATED THE REMEDY THE MANUFACTURING IS SUGGESTING IS A WARNING DEVICE NOT AN ACTUAL FIX TO THE PROBLEM. THE MANUFACTURED STATED THEY WOULD INSTALL A PRESSURE SENSOR IN THE CRANKCASE ESSENTIALLY TO WARN OF A PENDING ENGINE FAILURE.*JB
RECALL BY CUMMINS ON ISL850 ENGINES INSTALLED ON 2006/7 MONACO MOTORHOMES. THE RECALL DOES NOT ADDRESS THE POSSIBLE ENGINE FAILURE ISSUE. IT ONLY PROTECTS THE ENGINE FROM BLOWING UP THUS SAVING CUMMINGS MONEY. THE CORRECT FIX SHOULD BE A NEW ENGINE WHICH WOULD NOT HAVE THE UNCERTAINTY OF ENGINE FAILURE CAUSING THE VEHICLE (MOTORHOME ) TO BE STRANDED. *TR UPDATED 09/18/07.*JB
Too few reports in this category for a page of its own — they appear in the full complaint list.
Body & structure
Reports naming the vehicle structure, frame, body panels, doors, hood and trim.
From owner reports, verbatim
MOTOR HOME BY MONACO BROKEN FRAME TRAILING ARMS. *TR
Too few reports in this category for a page of its own — they appear in the full complaint list.
Fuel system
Reports naming fuel storage or delivery — tanks, pumps, lines, injectors and fuel leaks.
From owner reports, verbatim
WHILE TRAVELING IN MONTANA IN OUR 2006 MONACO DIPLOMAT MOTORHOME WITH THE CUMMINS ISL400 ENGINE A FUEL LEAK DEVELOPED IN THE ENGINE. THIS LEAK INVOLVED THE LINE FROM THE FUEL PUMP TO THE FUEL RAIL SPRAYING DIESEL FUEL ALL OVER THE ENGINE WHILE THE UNIT WAS RUNNING. MOTORHOME HAD TO BE TOWED 65 MILES TO BILLINGS, MT CUMMINS REPAIR FACILITY. A NEW FUEL LINE WAS INSTALLED, ALONG WITH A BRACKET WHICH IS NOW BEING INSTALLED ON THESE FAULTY LINES DUE TO THESE REPORTED FUEL LEAKS. NUMEROUS MOTORHOME OWNERS WITH THIS ENGINE HAVE REPORTED THIS POTENTIALLY DANGEROUS SITUATION TO BOTH CUMMINS AND VARIOUS COACH MANUFACTURERS. OWNERS ARE OF THE OPINION THAT A RECALL SHOULD BE ISSUED FOR THESE ENGINES DUE TO THE POTENTIAL OF A CATASTROPHIC ENGINE FIRE DUE TO THESE LEAKS. DRIVERS OF THESE UNITS WOULD NOT EVEN BE AWARE OF A FIRE ON THE COACH SINCE THE ENGINE IS AT THE REAR OF THE VEHICLE. *TR
Too few reports in this category for a page of its own — they appear in the full complaint list.
Higher-selling and older vehicles accumulate more reports. Counts are not failure rates and are not directly comparable between vehicles that sold in very different numbers.
Elsewhere on this vehicle
Data sources
- NHTSA Office of Defects Investigation — owner-reported complaints and the components recorded on them
Data on this page last refreshed .