2004 Monaco Coach Diplomat
Only 4 complaints on file — too few for a fair verdict.
This verdict reflects complaint volume compared to this model's typical year. Recalls and safety issues below apply regardless of the verdict — always check them.
Only 4 complaints on file — too few for a fair verdict. The data below is complete but unranked.
COMPLAINTS PER YEAR
View as data table
| Year | Complaints |
|---|---|
| 1998 | 1 |
| 1999 | 10 |
| 2000 | 14 |
| 2001 | 6 |
| 2002 | 2 |
| 2004 | 4 |
| 2005 | 1 |
| 2006 | 4 |
| 2007 | 1 |
| 2008 | 2 |
| 2009 | 1 |
| 2010 | 1 |
| 2011 | 1 |
KNOWN PROBLEM AREAS
Only 4 complaints on file for this model year -- too few to rank by share. Raw counts only, below.
2 of 4 total reports mention: visibility.
Show complaint excerpts
DEFROSTER NOT WORKING WINDSHIELDD ICED OVER WHEN DRIVING FROM SNOW. WHEN STOPED DEFROSTER WILL OUTPUT ENOUGH HEAT TO MELT ICE. HEATER DEFROSTER IS SUB STANDARD INSUFFICIENT HOT WATER FLOW FROM REAR MOUNTED DIESEL ENGINE TO HEATER CORE ABOUT 37FT.
NHTSA ODI report, 20050605
DEFROSTER NOT WORKING WINDSHIELD ICED OVER WHEN DRIVING FROM SNOW AND FREEZING RAIN.WHEN STOPED DEFROSTER WILL OUTPUT ENOUGH HEAT TO MELT ICE. HEATER DEFROSTER IS SUB STANDARD.
NHTSA ODI report, 20050526
2 of 4 total reports mention: structure.
Show complaint excerpts
DT: THE CALLER HAS A PROBLEM WITH THE FRONT ROADSIDE SLIDE ON THE MOTOR HOME. THEY HAD IT IN FOR REPAIR 8 DIFFERENT TIMES, AND IT STILL IS NOT FIXED. TO DATE THE ROADSIDE SLIDE IS UNSTABLE.
NHTSA ODI report, 20050824
2 of 4 total reports mention: service brakes, hydraulic.
2 of 4 total reports mention: electrical system.
1 of 4 total reports mentions: seats.
SAFETY TIMELINE
ON CERTAIN MOTORHOMES EQUIPPED WITH CUMMINS ENGINES, OIL CAN LEAK INTO THE ENGINE COMPARTMENT FROM A CRACK IN THE CUP PLUG.
Remedy: CUMMINS IS CONDUCTING THE OWNER NOTIFICATION AND REMEDY FOR THIS CAMPAIGN. CUMMINS WILL INSTALL A STEEL CUP PLUG BOSS CAP TO ALL AFFECTED ENGINES.
Campaign 04V441000 — check if this car was fixed
BUY-SMART CHECKLIST
2004 Monaco Coach Diplomat — pre-purchase inspection
- Test/inspect for visibility issues (2 reports on file for this year).
- Test/inspect for structure issues (2 reports on file for this year).
- Test/inspect for service brakes, hydraulic issues (2 reports on file for this year).
- Verify recall 04V441000 (engine and engine cooling) has been completed.
FAQ
Is the 2004 Monaco Coach Diplomat reliable?
There isn't enough NHTSA complaint data on file yet to give this model year a verdict.
What are the most common problems with the 2004 Monaco Coach Diplomat?
The most-reported component is visibility:defroster/defogger/hvac system:heater core, accounting for 50% of complaints on file.
How many recalls does the 2004 Monaco Coach Diplomat have?
1 recall on file for this model year.
Data updated 2026-07-11 · Complaints are unverified owner reports filed with NHTSA, not independently verified defects. Methodology.