"How reliable is the 2003 Mitsubishi Diamante?"

"Based on 75 NHTSA complaints, the 2003 Mitsubishi Diamante has a median complaint mileage of 60000 miles. The most common issue is Heater Core."

"What are common problems with the 2003 Mitsubishi Diamante?"

"The most frequently reported component in NHTSA complaints for the 2003 Mitsubishi Diamante is Heater Core, accounting for a significant portion of the 75 total complaints filed."

2003 Mitsubishi Diamante: Reliability Data

Source: NHTSA — 75 complaints

Total Complaints

60,000mi

Median Mileage

Heater Core

Top Issue

Crash Reports

When Do Complaints Happen?

Distribution of NHTSA complaints by vehicle mileage at time of report.

35,100 25th Percentile

60,000 Median Mileage

64,250 75th Percentile

What Fails?

Most reported component issues from NHTSA complaints.

Heater Core

Cooling System

Engine And Engine Cooling

Visibility

Rotor

Tires

Automatic Transmission

Antilock/Traction Control/Electronic Limited Slip

Front

Equipment

Severity Assessment

Crashes

Fires

Injuries

Deaths

Sample Complaint Reports

"2003/MITSUBISHI/DIAMANTE VR-X ON OCT 18 2003 I GOT MY NEW CAR AND IT HAS BEEN SHAKING AT ALL TIMES IT WAS IN ON MONDAY 20 TUESDAY 21 WEDNESDAY 22 FROM 22 OF OCT TO 27 I AM STILL NOT DRIVING MY CAR I HAV NO SEEN IT AND MY SHAKING IT STILL NOT FIXED.*AK"

"I HAVE A NEW 2003 MITSUBISHI DIAMANTE, WHICH IVE TAKEN BACK TO THE DEALERSHIP 3 TIMES NOW WITH THE SAME TWO ISSUES: THE FRONT BREAKS MAKE NOISE AND MY STEARING WHEEL VIBRATES WHEN I BRAKE AND THE CHECK ENGINE SERVICE SOON LIGHT KEEPS COMING ON.*AK ONE OF THE DEALERS EMPLOYEES TOLD ME THAT THE B..."

"THE FACTORY TIRES ON THIS VEHICLE ARE BAD. I HAVE GOTTEN 3 FLAT TIRES IN THE LAST 2 WEEKS. THEY WEAR DOWN EXTREMELY FAST AND BLOW OUT VERY EASILY.*AK"

Source: NHTSA ODI Complaints Database. Names and identifying details omitted.

When Were Complaints Filed?

Number of complaints by the year the issue occurred.

When Does Each Component Fail?

Median mileage at complaint for top components.

Heater Core 24 complaints

25th: 40,303 mi Median: 60,572 mi 75th: 64,750 mi

Cooling System 11 complaints

25th: 55,000 mi Median: 60,000 mi 75th: 74,838 mi

Engine And Engine Cooling 5 complaints

25th: 60,000 mi Median: 61,000 mi 75th: 64,750 mi

Where Are Complaints Coming From?

Top states by complaint count.

FL: 12 CA: 9 TN: 7 MA: 6 NC: 6 OH: 5 TX: 4 NJ: 3 AL: 3 NY: 2

Who Files Complaints?

28%

Original Owners

72%

Second+ Owners

Mitsubishi Diamante — Other Years

See how this model compares across different model years.

Year	Complaints	Median Mileage	Top Issue	Crashes
1992	60	-	Gasoline	2
1993	43	-	Frontal	10
1994	33	-	Frontal	6
1997	51	-	Automatic Transmission	3
1998	35	58,000	Heater Core	1
1999	26	88,450	Heater Core	0
2000	63	60,342	Heater Core	3
2001	93	60,000	Heater Core	0
2002	162	63,000	Heater Core	9

Data source: View this vehicle on NHTSA.gov | NHTSA ODI Complaints Database. Public domain.

Methodology: Complaint counts and mileage distributions are computed directly from consumer-reported NHTSA complaints. This data represents reported issues, not failure rates — vehicles without complaints are not represented. Full methodology.

Data through: 2026-03-28