2004 Monaco Coach Diplomat

Owner reports · Recalls · Investigations

Limited comparison data

There is not enough comparable history to draw a useful model-year comparison.

Counts are not adjusted for sales, age, mileage exposure or reporting. A lower count does not establish that a car is problem-free.

About this comparison →

4Owner complaints

Model-year median: 2

1Recall campaigns

View recall details →

0Investigations

View investigation details →

Check a VIN with NHTSA ↗ Model-level counts do not show whether a particular VIN is affected or repaired.

Inspection summary

2004 Monaco Coach Diplomat

NHTSA snapshot: September 18, 2026. 4 owner complaints · 1 recall campaigns · 0 investigations.

Counts are not failure probabilities and are not adjusted for sales, age, mileage exposure or reporting. One report may name several categories. Comparison method and limitations.

Top reported categories (up to 5)

Electrical System: 2 reports
Service Brakes, Hydraulic: 2 reports
Structure: 2 reports
Visibility: 2 reports
Equipment: 1 reports

Full reported-category list and vehicle report

Recall links

04V441000 — Engine And Engine Cooling:engine:diesel

Check a VIN with NHTSA. Model-level history does not establish whether a particular VIN is affected or repaired.

Print the top reported categories, recall links, snapshot date and comparison limits.

How this year compares

Owner complaints by model year

Other model years Selected year

Compare all Diplomat years →

Counts vary with age, sales, mileage exposure and reporting. They are not failure rates.

What owners reported most

Electrical System

2 Service Brakes, Hydraulic

2 Structure

2 Visibility

2 Equipment

All reported categories

Seats

Tap a category to read its complaints. One report may name several components.

When problems were reported

Mileage at the reported incident

Limited mileage data: 3 of 4 reports include usable mileage. There isn’t enough coverage to show a useful chart.

NHTSA’s mileage field refers to the reported incident, not necessarily the filing date. This shows report counts, not the likelihood of a failure.

What to inspect

Issues worth paying extra attention to based on owner reports.

Electrical System. Review the 2 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
Service Brakes, Hydraulic. Review the 2 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
Structure. Review the 2 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →

NHTSA owner reports · September 18, 2026 snapshot.

0 crash reports0 fire reports0 injury reports

Equipment complaints

1 reports

Clear category filter

Mileage unknown · Mar 25, 2005

Electrical SystemEquipmentService Brakes, Hydraulic

Read full complaint

DIPLOMAT 40PDQ 2004 MOTOR HOME, THE SLIDE WAS OFF CENTER AND STRIPS WERE NOT LINED UP PROPERLY. *BF THE SLIDE RIDES TO HIGH AND CAUSES SO MUCH WIND NOISE THAT THE CONSUMER WAS UNABLE TO HEAR OUTSIDE TRAFFIC. A GAP UNDER THE WINDOW ALLOWED WATER TO COMING INTO THE COACH. THE CAPTAIN DRIVER SEAT STARTED COMING APART AT THE PEDESTAL. WHEN APPLYING THE BRAKES SMOKE BILLOWED FROM THE REAR PASSENGER'S SIDE WHEEL. THE AIR CONDITIONER/HEAT PUMP KICKED THE CIRCUIT BREAKER. THE WINDSHIELD LEAKED IN THE CENTER ONTO THE DASH. CB GROUND PROBLEM. THE WASHER AND DRYING DID NOT WORK PROPERLY. THE HOLDING TANK WOULD NOT REGISTER PROPERLY. MANY ATTEMPTS HAVE BEEN MADE TO REPAIR THE COACH BUT NONE HAVE BEEN SUCCESSFUL. THE CONSUMER WOULD LIKE A FULL REFUND OF ALL MONEY PLUS ATTORNEY FEES OR A NEW COACH. NM

NHTSA ODI #10115850

Recall campaigns

04V441000 · Engine And Engine Cooling:engine:diesel

Sep 13, 2004

ON CERTAIN MOTORHOMES EQUIPPED WITH CUMMINS ENGINES, OIL CAN LEAK INTO THE ENGINE COMPARTMENT FROM A CRACK IN THE CUP PLUG.

Consequence & remedy

Consequence: OIL LEAKAGE ON A HOT ENGINE CAN RESULT IN AN ENGINE COMPARTMENT FIRE, POSSIBLY RESULTING IN INJURIES.

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. OWNERS SHOULD CONTACT CUMMINS CUSTOMER ASSISTANCE CENTER AT 1-800-343-7357 OR MONACO AT 1-800-685-6545.

Model-level recall history does not show whether a particular VIN is affected or has received a repair. Check a VIN with NHTSA ↗

Defect investigations

No exact-year investigations in this snapshot.

An investigation is not a finding of a defect, and closure does not prove a vehicle is problem-free.