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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

What owners actually said

56 reports
85,000 miles · Oct 18, 2008
Visibility

HEATER CORE LEAKAGE CAUSING SMOKE AND ANTIFREEZE ODOR TO COME OUT OF CAR VENTS AND UNDERNEATH DASH BOARD (PASSENGER SIDE). THERE IS A RISK OF ACCIDENT, PERSONAL INJURY, OR DEATH BECAUSE USE OF A/C, HEATER, AND DEFROST IS NOT AVAILABLE WHEN WINDSHIELDS AND WINDOWS FOG UP. *TR

NHTSA ODI #10245996

60,000 miles · Sep 3, 2008
Engine And Engine CoolingPower Train

I OWN A 2003 MITSUBISHI DIAMANTE, AROUND 60K MILES I STARTED NOTICING A SWEET SMELL FROM THE VENTS AND A CONSTANT FOG WHEN THE HEAT OR AIR WAS TURNED ON IN THE CAR. AFTER TAKING MY CAR TO THE MECHANIC I WAS TOLD THAT MY HEATER CORE WAS BUSTED. MY CAR ALSO SDRIVING IN "SAFE MODE" MEANING I CAN ONLY RUN IN SECOND GEAR WHICH IS BUR…

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I OWN A 2003 MITSUBISHI DIAMANTE, AROUND 60K MILES I STARTED NOTICING A SWEET SMELL FROM THE VENTS AND A CONSTANT FOG WHEN THE HEAT OR AIR WAS TURNED ON IN THE CAR. AFTER TAKING MY CAR TO THE MECHANIC I WAS TOLD THAT MY HEATER CORE WAS BUSTED. MY CAR ALSO SDRIVING IN "SAFE MODE" MEANING I CAN ONLY RUN IN SECOND GEAR WHICH IS BURNING A TANK OF GAS EVERY THREE DAY, I LOVE 10 MILES FROM WORK. MY CAR FLASHED IN NEUTRAL WILL IN DRIVE. AFTER RESEARCHING MY PROBLEMS I'VE NOTICE WELL OVER 1000 POSTED VIA INTERNET FROM OTHER MITSUBISHI DIAMANTE OWNERS HAVING THE SAME ISSUE. ITS HARD TO BELIEVE THIS VEHICLE HAS NOT BE RECALLED. THERE ARE GREAT RISKS OF INHALING ANTI FREEZE WHICH IS SEEPING INTO THE CAR THROUGH THE FLOOR BOARDS AND VENTS. I HAVE AN ASTHMATIC CHILD WHO HAS BEEN DRIVING IN THE CAR UNTIL THE PROBLEM WAS BROUGHT TO MY ATTENTION. THIS LEAK MAY ALSO MAKE THE COMPUTER SYSTEM IN THE VEHICLE GO OUT. SOMETHING NEEDS TO BE DONE BEFORE AN ACCIDENT IS CAUSED OR A LIFE IS TAKEN. *TR

NHTSA ODI #10240783

114,132 miles · May 1, 2008
Engine And Engine CoolingPower Train

MY TRANSMISSION RELAY WENT OUT DUE TO A LEAK HEATER CORE. THE CORE HAS BEEN LEAKING FOR SOME TIME AND HAS FOGGED MY WINDOWS SO BAD I COULD NOT SEE AT TIMES, HAVING TO PULL OVER AND WIPE OFF THE FILM. THIS IS A SERIOUS PROBLEM WITH THESE CARS. *TR

NHTSA ODI #10226354

78,000 miles · Apr 16, 2008
Engine And Engine CoolingPower Train

I OWN A 2003 DIAMANTE MITSUBISHI. THE PROBLEM STARTED WITH A CHECK ENGINE LIGHT COMING ON, FOGGING THE WINDOW WITH A FOWL TOXIC SMELL THEN THE CAR WOULD NOT HARDLY MOVE OUT GEAR. I WAS TOLD THAT THE CAR'S HEATER CORE LEAKED ONTO THE COMPUTER WHICH CAUSED THE TRANSMISSION RELAY TO SHORT OUT DO TO THE COMPUTER FAILING. THE COMPUT…

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I OWN A 2003 DIAMANTE MITSUBISHI. THE PROBLEM STARTED WITH A CHECK ENGINE LIGHT COMING ON, FOGGING THE WINDOW WITH A FOWL TOXIC SMELL THEN THE CAR WOULD NOT HARDLY MOVE OUT GEAR. I WAS TOLD THAT THE CAR'S HEATER CORE LEAKED ONTO THE COMPUTER WHICH CAUSED THE TRANSMISSION RELAY TO SHORT OUT DO TO THE COMPUTER FAILING. THE COMPUTER WAS STILL UNDER WARRANTY AT 78,000 MILES BUT I STILL HAD TO PAY FOR THE NEW COMPUTER SYSTEM BECAUSE I WAS TOLD THAT IT WAS THE HEATER CORE THAT CAUSED THE COMPUTER TO FAIL. THIS IS SUCH A POOR DESIGN! THE COMPUTER SHOULD HAVE BEEN PROTECTED IN SUCH A CASE...FUNNY THING IT IS NOW THAT I HAVE HAD TO REPLACE A HEATER CORE, A COMPUTER AND A TRANSMISSION RELAY AT A CUT WRENCHING COST OF $3,675.58. I WROTE A LETTER TO THE PRESIDENT OF NORTH AMERICA MITSUBISHI THAT THE HEATER CORE SHOULD BE A RECALL BUT TO NO AVAIL. I HAVE ALL MAINTENANCE RECORDS ON THE DIAMANTE SO THAT WAS NOT WHAT CAUSED THIS HEATER FAILURE. I DO HAVE THE COMPUTER THAT WAS REPLACED. IT IS NOW APRIL AND THE CHECK ENGINE LIGHT HAS COME BACK ON...NOW WHAT? AJ *TR

NHTSA ODI #10224750

84,900 miles · Apr 7, 2008
Visibility

DRIVING ALONG AND WINDOWS STARTED TO FOG UP, AND STARTED SMELLING A ODD ODOR. FOUND OUT MY HEATER CORE WAS BAD. APPARENTLY CRACKED FOR NO REASON. RIGHT NOW BY-PASSED THE HEATER CORE BECAUSE MITSUBISHI DEALER QUOTED $1,800.00 TO FIX IT. IT APPEARS TO BE A BIG PROBLEM WITH THE DIAMANTE'S. *TR

NHTSA ODI #10223547

20 miles · Apr 7, 2008
Engine And Engine CoolingVisibility

I HAVE 2003 MITSUBISHI DIAMANTE. MY "CHECK ENGINE" LIGHT CAME ON, SO I TOOK IT IN FOR SERVICE, AND MY HEATER CORE WAS LEAKING ON MY COMPUTER...NOW IT'S GOING TO COST ME AROUND 3,500 DOLLARS....THIS IS A VERY FLAWED DESIGN. THERE SHOULD BE A RECALL ON THIS ITEM. *TR

NHTSA ODI #10223524

Mileage unknown · Mar 18, 2008
Visibility

I BOUGHT AN 2003 MITSUBISHI DIAMANTE IN 2005. MY WIFE AND I NOTICED AN OCCASIONALLY "SYRUP" SMELL, BUT DIDN'T THINK MUCH OF IT. THIS WEEK END (MARCH 08)ANTI-FREEZE (COOLANT) BEGAN TO COME OUT OF THE VENTS IN A MIST. IT EVEN TURNED THE BOTTOM HALF OF MY FRONT WINDSHIELD GREEN CREATED A FILM ON THE WINDOWS WHICH MADE IT HARD TO SE…

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I BOUGHT AN 2003 MITSUBISHI DIAMANTE IN 2005. MY WIFE AND I NOTICED AN OCCASIONALLY "SYRUP" SMELL, BUT DIDN'T THINK MUCH OF IT. THIS WEEK END (MARCH 08)ANTI-FREEZE (COOLANT) BEGAN TO COME OUT OF THE VENTS IN A MIST. IT EVEN TURNED THE BOTTOM HALF OF MY FRONT WINDSHIELD GREEN CREATED A FILM ON THE WINDOWS WHICH MADE IT HARD TO SEE. I HAVE A NEW BORN CHILD THAT IS NOW SICK AS WELL MYSELF AND MY 2 1/2 YEAR OLD. THEY HAVE A DOCTORS APPOINTMENTS TOMORROW AND I HOPE THEY ARE NOT SICK FROM THE CAR. ESTIMATED COST TO FIX WAS ABOUT $1150. *TR

NHTSA ODI #10221561

67,000 miles · Dec 23, 2007
Visibility

I OWN A 2003 MITSUBISHI DIAMANTE LS WITH 70,000. I PURCHASED THE CAR FROM THE DEALERSHIP BRAND NEW. IN NOVEMBER 2007, THERE WAS A STRONG SMELL OF ANTIFREEZE IN THE CAR. AFTER SOME INVESTIGATION, IT WAS DISCOVERED THERE WAS A LEAK IN THE HEATING CORE, WHICH WAS CAUSING THE ANTIFREEZE TO LEAK OUT OF THE COMPARTMENT AND INTO THE…

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I OWN A 2003 MITSUBISHI DIAMANTE LS WITH 70,000. I PURCHASED THE CAR FROM THE DEALERSHIP BRAND NEW. IN NOVEMBER 2007, THERE WAS A STRONG SMELL OF ANTIFREEZE IN THE CAR. AFTER SOME INVESTIGATION, IT WAS DISCOVERED THERE WAS A LEAK IN THE HEATING CORE, WHICH WAS CAUSING THE ANTIFREEZE TO LEAK OUT OF THE COMPARTMENT AND INTO THE CABIN OF THE CAR...NEEDLESS TO SAY, THE CAR IS UNDRIVEABLE BECAUSE OF THE HEALTH RISKS ASSOCIATED WITH BREATHING ANTIFREEZE. ESTIMATED REPAIRS ARE AROUND $1500. THIS IS COMPLETELY RIDICULOUS!!!! I AM OUTRAGED TO SEE THAT SO MANY 2003 DIAMANTE OWNERS ARE HAVING THE SAME PROBLEM. I BELIEVE AN INVESTIGATION NEEDS TO BE CONDUCTED, AND MITSUBISHI MOTORS SHOULD BE HELD ACCOUNTABLE FOR THIS!!! *TR

NHTSA ODI #10212610

37,813 miles · Dec 19, 2007
Visibility

37813 MILES. HEATER CORE LEAKING. NOTICE THE SWEET SMELL AND NOW OVERHEATING OCCURS. *TR

NHTSA ODI #10212356

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

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.