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2003 Mitsubishi Diamante

Owner reports · Recalls · Investigations

Similar to other model years

Owner complaints for the 2003 Mitsubishi Diamante do not stand out strongly from the model-year median of 31.5.

About this comparison →

How this year compares

Owner complaints by model year

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

What owners reported most

All reported categories

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

When problems were reported

Mileage at the reported incident

44 reports with mileage · 12 unknown

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.

  • Visibility. Review the 28 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
  • Engine And Engine Cooling. Review the 17 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
  • Power Train. Review the 4 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →

NHTSA owner reports · September 18, 2026 snapshot.

1 crash reports0 fire reports1 injury reports

Engine And Engine Cooling complaints

17 reports
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86,000 miles · Dec 8, 2007
Engine And Engine CoolingVisibility

THIS IS A MITSUBISHI DIAMANTE 2003 ES. I'M EXPERIENCING A SWEET SMELL OF ANTI-FREEZE INSIDE THE CAR AS SOON AS I TURN ON HEATING. ANTI-FREEZE CONTAINS ETHYLENE GLYCON AND THE FUMES ARE HIGHLY TOXIC. FIXING THE HEATER CORE WILL COST $1300. I AM FILING THIS COMPLAINT TO ASCERTAIN THAT THIS IS A VERY VERY COMMON PROBLEM IN MITSUBI…

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THIS IS A MITSUBISHI DIAMANTE 2003 ES. I'M EXPERIENCING A SWEET SMELL OF ANTI-FREEZE INSIDE THE CAR AS SOON AS I TURN ON HEATING. ANTI-FREEZE CONTAINS ETHYLENE GLYCON AND THE FUMES ARE HIGHLY TOXIC. FIXING THE HEATER CORE WILL COST $1300. I AM FILING THIS COMPLAINT TO ASCERTAIN THAT THIS IS A VERY VERY COMMON PROBLEM IN MITSUBISHI DIAMANTE AND MITSUBISHI MOTORS SHOULD BE AWARE OF THREE MAIN RISK ASSOCIATED WITH THIS: (1) THE DEFECT EXPOSES CUSTOMERS TO UNUSUAL LEVEL OF TOXIC ETHYLENE GLYCOL WHICH SHOULD NOT EXCEED 10-25 PPM LEVELS (CONSULT MSDS FOR ETHYLENE GLYCOL) (2) THE LEAK CAN AFFECT THE CAR'S MICROPROCESSOR AND POSES A SEVERE HAZARD FOR DRIVERS. (3) FAULTY HEATER CORE MAKES THE VISIBILITY DIFFICULT DUE TO FOGGING OF WINDSHIELD THUS PUTTING THE DRIVER AT GREATER RISK. I WILL EVENTUALLY FIX THE PROBLEM BY SPENDING $1300 IF MITSUBISHI REFUSES TO ISSUE A RECALL. RIGHT NOW I AM TRYING SOME RADIATOR ANTI-LEAK TO DELAY THE COSTLY REPAIR. BUT I WANT NHTSA TO BE AWARE OF THE HAZARDS THAT HAS BEEN IGNORED BY THE MANUFACTURER. *TR

NHTSA ODI #10211220

Mileage unknown · Nov 5, 2007
Engine And Engine Cooling

2003 DIAMANTE ISSUES. STARTED SMELLING A SYRUPY TYPE SMELL, COOLANT SMELL THROUGHOUT THE CABIN AND HAD FUMES ESCAPING THROUGH THE VENT IN THE CAR. COOLANT LEVEL DROPPING WITH NO VISIBLE SIGNS ON THE GROUND. LOOKS TO BE THE HEATER CORE. NOTHING HAS BEEN DONE YET. SEEN MULTIPLE COMPLAINTS REGARDING THE SAME ISSUE AND ON THIS SITE.…

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2003 DIAMANTE ISSUES. STARTED SMELLING A SYRUPY TYPE SMELL, COOLANT SMELL THROUGHOUT THE CABIN AND HAD FUMES ESCAPING THROUGH THE VENT IN THE CAR. COOLANT LEVEL DROPPING WITH NO VISIBLE SIGNS ON THE GROUND. LOOKS TO BE THE HEATER CORE. NOTHING HAS BEEN DONE YET. SEEN MULTIPLE COMPLAINTS REGARDING THE SAME ISSUE AND ON THIS SITE. WONDERING WHY SO MANY COMPLAINTS HAVE BEEN SENT, BUT NOTHING DONE YET? *TR

NHTSA ODI #10207934

42,900 miles · Jul 10, 2007
Engine And Engine Cooling

MAPLE SYRUP SMELL FROM AIR VENTS THEN CAR STARTED TO OVERHEAT HEATERCORE FAILURE, ANTIFREEZE IN FLOORBOARDS ON WINDSHIELD AND COMING THROUGH AIR VENTS. A NEW HEATERCORE INSTALLED VERY COSTLY HAD TO DO WORK MYSELF BECAUSE WARRANTY EXPIRED. HAD TO SHAMPOO CARPETS AND BUY NEW FLOORMATS BECAUSE THE ANITFREEZE RUINED THEM. AFTER R…

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MAPLE SYRUP SMELL FROM AIR VENTS THEN CAR STARTED TO OVERHEAT HEATERCORE FAILURE, ANTIFREEZE IN FLOORBOARDS ON WINDSHIELD AND COMING THROUGH AIR VENTS. A NEW HEATERCORE INSTALLED VERY COSTLY HAD TO DO WORK MYSELF BECAUSE WARRANTY EXPIRED. HAD TO SHAMPOO CARPETS AND BUY NEW FLOORMATS BECAUSE THE ANITFREEZE RUINED THEM. AFTER READING MANY COMPLAINTS YOU WOULD THINK THAT A RECALL WOULD BE MADE. JUST BECAUSE NO DEATHS THE CONSUMER SHOULD SUFFER. WHAT ABOUT THE MONEY THAT IT TOOK TO MAKE THE REPAIR. THAT WAS MONEY TAKEN FROM MY FAMILY THAT WE USE TO FEED US AND HAVE SHELTER. COME ON YOU HAVE TO AUTHORITY TO DO SOMETHING SO WHY DON'T YOU. *TR

NHTSA ODI #10195947

53,000 miles · Jun 18, 2007
Engine And Engine Cooling

FIRST THE WINDSHIELD ON THE MITSUBISHI DIAMANTE 2003 LS FOGGED UP, LATER FUMES STARTED TO COME OUT OF THE VENTS. ALSO, NOTICED DAMP CARPET ON FRONT PASSENGER SIDE. CLOSE INSPECTION INDICATED COOLENT WAS LEAKING ON THE CARPET. *AK I TOOK THE CAR TO LOCAL DEALERSHIP FOR REPAIRS. SERVICE TECHNICIAN AT THE DEALERSHIP DIAGOSED TH…

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FIRST THE WINDSHIELD ON THE MITSUBISHI DIAMANTE 2003 LS FOGGED UP, LATER FUMES STARTED TO COME OUT OF THE VENTS. ALSO, NOTICED DAMP CARPET ON FRONT PASSENGER SIDE. CLOSE INSPECTION INDICATED COOLENT WAS LEAKING ON THE CARPET. *AK I TOOK THE CAR TO LOCAL DEALERSHIP FOR REPAIRS. SERVICE TECHNICIAN AT THE DEALERSHIP DIAGOSED THE PROBLEM WITH HEATER CORE AND THE HOSE CONNECTING TO THE HEATING SYSTEM FAULTY. COOLENT FUMES ARE TOXIC AND CAN CAUSE SEVERE INJURY. I AM HOPING THAT NHTSA WILL TAKE ACTION AND MITSUBHI WILL REIMBURSE ME AND OTHERS FOR THE CHARGES TO REPLACE FAULTY EQUIPMENT.

NHTSA ODI #10193641

60,000 miles · Mar 31, 2007
Engine And Engine CoolingVisibility

2003 MITSUBISHI DIAMANTE COOLANT LEAK INSIDE THE CAR. STEAM FOGGING THE WINDOWS AND STRONG CHEMICAL ODOR LEAVING RESIDUE ON WINDOWS. QUOTED $1000 TO REPAIR, THEY SAY IT NEEDS A NEW HEATER CORE. IT MAY NOT BE THE HEATER CORE, BUT JUST SEALS. I HAVE BYPASSED THE HEATER HOSES AND FORTUNATELY LIVE IN A WARM AREA. *JB

NHTSA ODI #10186639

73,000 miles · Jan 29, 2007
Engine And Engine Cooling

ON FRIDAY, JAN 19, 2007, I WENT TO MY 2003 MITSUBISHI DIAMANTE VRX AFTER WORK TO GO HOME. WHEN I GOT TO IT, ALL WINDOWS WERE TOTALLY FOGGED OVER, WHICH IS ABNORMAL. WITH HIGH HEAT, I WAS ABLE TO CLEAR A PORTION OF THE WINDSHIELD, RELYING ON A PAPER TOWEL TO CLEAR THE REMAINDER. I PARKED THE VEHICLE FOR ABOUT 2 HOURS AFTER ARR…

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ON FRIDAY, JAN 19, 2007, I WENT TO MY 2003 MITSUBISHI DIAMANTE VRX AFTER WORK TO GO HOME. WHEN I GOT TO IT, ALL WINDOWS WERE TOTALLY FOGGED OVER, WHICH IS ABNORMAL. WITH HIGH HEAT, I WAS ABLE TO CLEAR A PORTION OF THE WINDSHIELD, RELYING ON A PAPER TOWEL TO CLEAR THE REMAINDER. I PARKED THE VEHICLE FOR ABOUT 2 HOURS AFTER ARRIVING AT HOME AND HAD TO RELY ON PAPER TOWELS TO CLEAR THE WINDSHIELD ONCE AGAIN. THIS TIME, I NOTICED A DISTINCT ANTIFREEZE SMELL. THE FOLLOWING DAY, THE SUNLIGHT SHOWED THE FILM TO BE OF A GREEN COLOR. AT THIS TIME, I REALIZED THAT THE WINDOWS WEREN'T FOGGY, BUT IT SEEMED THAT ANTIFREEZE VAPORS WERE BLOWING INTO MY CAR. AFTER SOME RESEARCH ON THE DIAMANTE OWNERS' GROUP WEBSITE, IT WAS EVIDENT THAT THE HEATER CORE OR O-RINGS WERE CAUSING THIS. I TOOK THE VEHICLE TO LAWSON MITSUBISHI, WHERE IT IS BEING REPAIRED. THIS IS SOMETHING THAT HAPPENED WITH LITTLE IDENTIFIABLE WARNING. HAD THIS HAPPENED ON THE ROAD, AN ACCIDENT WOULD HAVE SURELY ENSUED. *NM

NHTSA ODI #10180963

65,000 miles · Nov 8, 2006
Engine And Engine CoolingVisibility

2003 MITSUBISHI DIAMANTE WITH 65000 MILES. NOTICED FOG COMING OUT OF VENTS AROUND THE RADIO. IT SMELLED LIKE ANTI-FREEZE AND CREATED A FOG ON MY WINDOWS THAT WAS BAD ENOUGH TO RENDER THE CAR UNDRIVEABLE. I WAS ALSO GETTING AN ERROR MESSAGE OF P-1751. THIS REFERS TO A PROBLEM WITH THE TRANSMISSION RELAY CONTROL. I TOOK THE CAR TO…

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2003 MITSUBISHI DIAMANTE WITH 65000 MILES. NOTICED FOG COMING OUT OF VENTS AROUND THE RADIO. IT SMELLED LIKE ANTI-FREEZE AND CREATED A FOG ON MY WINDOWS THAT WAS BAD ENOUGH TO RENDER THE CAR UNDRIVEABLE. I WAS ALSO GETTING AN ERROR MESSAGE OF P-1751. THIS REFERS TO A PROBLEM WITH THE TRANSMISSION RELAY CONTROL. I TOOK THE CAR TO A TRANSMISSION SHOP AND AFTER DIAGNOSING FOR TWO DAYS, THE MECHANIC TOLD ME THAT HE HAD DISCOVERED A LEAKING HEATER COIL THAT MAY OR MAY NOT HAVE DAMAGED THE PCM. WORST CASE SCENARIO, $1600. IT WILL AT LEAST COST $500, BEST CASE SCENARIO. I UNCOVERED NUMEROUS COMPLAINTS FROM DIAMANTE OWNERS WITH MODELS FROM A WIDE RANGE OF YEARS WHO WERE EXPERIENCING THE SAME PROBLEMS. THIS IS CRIMINAL NEGLIGENCE AND I PERSONALLY REQUEST AN INVESTIGATION TO RESEARCH HOW MISTUBISHI HAS BEEN GETTING AWAY WITH THIS, FOR SO LONG. THE SAME EXACT PROBLEMS ARE OCCURRING ON A FREQUENT BASIS. *JB

NHTSA ODI #10172928

Official recalls

2

04V428000 · Equipment:other:labels

Sep 1, 2004

CERTAIN PASSENGER VEHICLES FAIL TO CONFORM TO THE REQUIREMENTS OF FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 208, 'OCCUPANT CRASH PROTECTION.' THE BILINGUAL ENGLISH/SPANISH REMOVABLE AIR BAG WARNING LABELS AFFIXED TO THE DASH AND TO THE SUNVISOR DO NOT MEET THE SIZE REQUIREMENTS OF THE STANDARD.

Consequence & remedy

Consequence: THIS DOES NOT MEET THE REQUIREMENTS OF THE STANDARD.

Remedy: MITSUBISHI CARIBBEAN WILL MAIL A CUSTOMER NOTIFICATION LETTER CONTAINING A WRITTEN DESCRIPTION AND A GRAPHIC OF THE BI-LINGUAL DASHBOARD AIR BAG WARNING LABEL. IN ADDITION, ALL CURRENT 2000-2004 NATIVA OWNERS WILL ALSO RECEIVE REPLACEMENT AIR BAG ALERT LABELS FOR THE SUN VISORS. THIS RECALL IS EXPECTED TO BEGIN DURING MARCH OR APRIL 2005. THE NOTIFICATION TO THE NATIVA OWNERS IS EXPECTED TO BEGIN DURING APRIL OR MAY 2005. OWNERS SHOULD CONTACT MITSUBISHI CARIBBEAN AT 1-787-251-8715.

04V067000 · Equipment:other:owners/service/other Manual

Feb 11, 2004

CERTAIN SPORT UTILITY AND PASSENGER VEHICLES FAIL TO COMPLY WITH FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 225, "CHILD RESTRAINT ANCHORAGE SYSTEMS." THE OWNER'S MANUAL DOES NOT CONTAIN A STEP-BY-STEP DESCRIPTION FOR HEADREST ADJUSTMENT WHEN INSTALLING A CHILD RESTRAINT SYSTEM (CRS) TETHER STRAP.

Consequence & remedy

Consequence: IF THE TETHER STRAP IS IMPROPERLY INSTALLED TO THE TETHER ANCHOR, THE CHILD SAFETY SEAT MAY NOT BE SUFFICIENT RESTRAINED. IN THE EVENT OF A CRASH, THE CHILD COULD BE INJURED.

Remedy: A LETTER OUTLINING THE PROBLEM WILL BE SENT TO OWNERS ALONG WITH A STICKER CONTAINING THE CORRECT INSTRUCTIONS AS WELL AS INSTRUCTIONS ON WHERE TO AFFIX THE STICKER IN THE OWNER'S MANUAL. THE RECALL BEGAN ON MARCH 29, 2004. OWNERS SHOULD CONTACT MITSUBISHI AT 1-888-648-7820.

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

NHTSA investigations

0

No exact-year investigations in this snapshot.