Total Complaints
35 filings
MITSUBISHI DIAMANTE · model year
35 NHTSA complaints, 1 crash report for this specific cohort.
NHTSA overall rating
Not crash-tested
New Car Assessment Program
The 1998MITSUBISHIDIAMANTE carries 35 consumer safety complaints in NHTSA's Office of Defects Investigation database for this specific model-year cohort. Within that volume, owners reported 1 crash, 0 fires, 4 injuries, and 0 fatalities. No NCAP 5-star crash-test rating is available for this model year in the federal database.
Component-level analysis is where model-year complaints become actionable: the top complaint category for the 1998 DIAMANTE is visibility:defroster/defogger/hvac system:heater core with 13 filings, followed by service brakes, hydraulic:foundation components:disc (2) and visibility:windshield wiper/washer (1). Concentration in one or two component groups is the classic signature of a systemic defect; a flat distribution usually reflects normal aging, warranty complaints, or isolated build-plant variability.
NHTSA currently has 14 investigation files overlapping the 1998 DIAMANTE. Owners comparing this cohort against neighboring years should pair the counters above with the complaint-by-year trend on the parent model page — a spike in a single year often tracks to a platform refresh, a new transmission supplier, or an updated ECU calibration. Use the related-complaint feed below to read raw owner narratives before deciding whether any pattern here affects your specific use case.
Total Complaints
35 filings
Crashes Reported
1 reports
Source
NHTSA ODI
Federal complaints database
At or below the fleet median complaint volume.
| Component | Count |
|---|---|
| VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM:HEATER CORE | 13 |
| SERVICE BRAKES, HYDRAULIC:FOUNDATION COMPONENTS:DISC | 2 |
| VISIBILITY:WINDSHIELD WIPER/WASHER | 1 |
| VEHICLE SPEED CONTROL | 1 |
| SERVICE BRAKES, HYDRAULIC:ANTILOCK/TRACTION CONTROL/ELECTRONIC LIMITED SLIP | 1 |
| WHEELS:LUGS/NUTS/BOLTS/STUDS | 1 |
| ELECTRICAL SYSTEM:IGNITION:MODULE | 1 |
| TIRES | 1 |
| STEERING:HYDRAULIC POWER ASSIST:POWER STEERING FLUID | 1 |
| STRUCTURE:BODY:DOOR | 1 |
| STRUCTURE:BODY | 1 |
| EQUIPMENT:ELECTRICAL:RADIO/TAPE DECK/CD ETC. | 1 |
| SEAT BELTS:REAR/OTHER | 1 |
| VEHICLE SPEED CONTROL:ACCELERATOR PEDAL | 1 |
| ENGINE AND ENGINE COOLING:COOLING SYSTEM:RADIATOR ASSEMBLY | 1 |
THE HEATER CORE HAS FAILED (ONCE AGAIN) I AM NOT SURE OF ANY COMPANY THAT HAS REALEASED THEIR CARS WITH SUCH A MAJOR FAILURE WITHOUT TAKING SOME KIND OF RESPONSIBILITY TO RECALL THIS ITEM IN THE CAR. NEARLY ALL OF THE HEATER CORES FROM MITSUBISHI DIAMANTES THAT I HAVE SEEN ARE ALL BAD. LEAKS ONTO THE ECU AND CAUSES A WHOLE HECK LOAD OF PROBLEMS. PLEASE DOT HAVE MITSUBISHI RECALL THIS. AS TO THIS CAUSES IMMENSE DAMAGES AND PEOPLE LIKE ME DRIVING AROUND WITH THIS FAULTY PIECE ARE BREATHING IN THE FUMES AND DRIVING WITH NEARLY FULL FOGGED WINDSHIELDS CAUSING REALLY POOR VISIBILITY WHICH IS AN EXTREME HAZARD TO OUR ROADS AND FELLOW PEDESTRIANS PLEASE I URGE YOU TO TAKE THIS COMPLAINT SERIOUS AND USE YOUR DOT POWERS TO MAKE THIS MANUFACTURER DO WHAT IS RIGHT! THANKS FOR YOUR TIME
Mileage: 171,000
WE JUST CLEARED CANADIAN CUSTOMS AT BLAINE WA, PACIFIC CROSSING, AND WERE ACCELERATING TO SPEED LIMIT ON I 5 FREEWAY WHEN THE CAR ACCELERATED TO NEAR 100 MILES AN HOUR. THE TACH AT SOME POINT WAS 7500 AND INCREASING. THE ACCELERATOR WAS STUCK AND EVENTUALLY WE WERE ABLE TO GET TO THE EMERGENCY LANE AREA AND TURNED OF THE IGNITION KEY. FULL PRESSURE ON THE BRAKES WOULD NOT SLOW IT DOWN MUCH. *TR WE WERE TOWED 21 MILES TO DAVIS AUTOMOTIVE IN BELLINGHAM, WA, WHERE A REPLACEMENT THROTTLE CABLE AND ASSOCIATED STRUCTURE WAS SEVERELY BENT AND THE CABLE HAD CUT THRU IT AND STUCK. *MEC THE CONSUMER HAD THE VEHICLE TOWED WHERE A REPLACEMENT THROTTLE CABLE WAS INSTALLED. UPDATED 10/10/08. *JB
Mileage: 31,385
THIS IS THE SECOND TIME THE HEATER CORE HAS STARTED TO LEAK. IT WAS REPLACED 40K MILES AGO AND I WAS CHARGED $ 1,000 FOR REPAIR COSTS. HAVING RESEARCHED THIS, IT IS DUE TO FAULTY HEATER CORE GASKETS WHICH MITSUBISHI REPLACED THE DEFECTIVE GASKETS WITH A REDESIGNED ONE. THE CAR IS UNDRIVABLE DUE TO THE TOXIC FUMES FROM THE ETHYLENE GLYCOL COMING OUT OF ALL THE VENTS AND I DO NOT HAVE THE MONEY TO GET IT REPAIRED. MITSUBISHI REFUSES TO DO ANYTHING ABOUT IT, AND NEARLY EVERY DIAMANTE ON THE ROAD HAS HAD THIS HAPPEN. THE CARPET IS RUINED FROM THE COOLANT LEAK AS WELL, AND MANY HAVE HAD THE ECU FOR THE TRANSMISSION FAIL DUE TO COOLANT LEAKING ON IT. *TR
Mileage: 132,000
WILL NOT PASS EMISSION THERE ARE NO READINESS CODES STORED IN COMPUTER. *TR
Mileage: 900,000
EVERYTIME THE HEATER IS SWITCHED ON, I CAN FEEL A WEIRD SMELL WHICH WILL LAST FOR ABOUT 10 MINS. THIS SMELL SEEMS LIKE SUFFOCATING AND HAVE TO OPEN THE WINDOWS FOR THE FRESH AIR TO ENTER. THERE IS SOME KIND OF LEAK IN THE ENGINE COMPARTMENT, I AM NOT SURE WHERE THE LEAK IS FROM. I AM BIT WORRIED ABT THE SMELL. THANKS *TR
FAILURE OF HEATER CORE GASKETS RESULTING IN FUMES INSIDE THE CAR FROM ANTI-FREEZE; THIS IS THE 2ND TIME THIS HAS HAPPENED WITH THIS VEHICLE IN THE LAST 35,000 MILES AND THE REPAIR LABOR IS ESTIMATED AT 6 HOURS, WHICH IS AROUND $1,000. *JB
Mileage: 131,000
1998 MITSUBISHI DIAMANTE HEATER CORE LEAKING FOGGING WINDSHIELD DURING FREEWAY TRAVEL. HAZARD TO HEALTH WITH WHILE OPERATION AUTO. *NM
Mileage: 74,000
WINDOWS FOG UP AND CANNOT BE CLEARED BY THE DEFROSTER. VERY STRONG SMELL OF ANTI-FREEZE INSIDE THE CAR. SMOKEY VAPORS COME OUT OF THE HEATING VENTS. I'M HAVING DIFFICULTY BREATHING WHILE DRIVING MY CAR, AND BELIEVE THE CAUSE OF MY NAUSEA AND HEADACHE IS DUE TO BREATHING ANTI-FREEZE VAPORS. STAIN ON PASSENGER SIDE OF CARPET. ALL THESE SYMPTOMS INDICATE A HEATER CORE PROBLEM.*AK
Mileage: 78,000
WHILE DRIVING CONSUMER SMELLED A BAD ODOR COMING FROM THE HEATER CORE. HEATER SYSTEM WAS LEAKING COOLANT. THIS HAPPENED THREE TIMES. THE SEAL HAD TO BE REPLACED. *AK THE VEHICLE'S HEATER CORE AND REFRIGERANT WERE REPLACED. *NM
Mileage: 50,000
I OWN A PREOWNED 1998 MISTUBISHI DIAMANTE LS. WHEN THE CLIMATE CONTROL, PARTICULARLY THE HEATER IS ENGAGED, THE SMELL OF ANTI-FREEZE BECOMES QUITE APPARENT. DEALER CLAIMED 2 YEARS AGO WHEN I BOUGHT IT THAT IT WAS THE SMELL OF THE CHEMICALS USED TO CLEAN THE CAR DURING "MAKE-READY." ETHYLEN GLYCOL FUMES ARE TOXIC AND THIS IS A REOCCURING DEFECT IN THIS MODEL CAR FROM POSTS I HAVE SEEN ON VARIOUS WEBSITES. I WAS LATER TOLD THAT TO FIX THIS PROBLEM WILL COST CLOSE TO $1000 SINCE THE CAR IS OUT OF WARRANTY. MITSUBISH ISSUED A TSB ADDRESSING THIS PROBLEM, OBVIOUSLY THEY ARE AWARE OF IT. IN ADDITION, THE WINDSHIELD IS COVERED WITH A FILM THAT CANNOT BE WASHED OFF FROM THIS LEAK. A RECALL SHOULD BE ISSUED FOR THIS PROBLEM, I AM NOT THE FIRST PERSON TO FILE THIS COMPLAINT ON YOUR WEBSITE. THANK YOU.*AK
Mileage: 58,000
I OWN A PREOWNED 1998 MISTUBISHI DIAMANTE LS. WHEN THE CLIMATE CONTROL, PARTICULARLY THE HEATER IS ENGAGED, THE SMELL OF ANTI-FREEZE BECOMES QUITE APPARENT. DEALER CLAIMED 2 YEARS AGO WHEN I BOUGHT IT THAT IT WAS THE SMELL OF THE CHEMICALS USED TO CLEAN THE CAR DURING "MAKE-READY." ETHYLEN GLYCOL FUMES ARE TOXIC AND THIS IS A REOCCURING DEFECT IN THIS MODEL CAR FROM POSTS I HAVE SEEN ON VARIOUS WEBSITES. I WAS LATER TOLD THAT TO FIX THIS PROBLEM WILL COST CLOSE TO $1000 SINCE THE CAR IS OUT OF WARRANTY. MITSUBISH ISSUED A TSB ADDRESSING THIS PROBLEM, OBVIOUSLY THEY ARE AWARE OF IT. IN ADDITION, THE WINDSHIELD IS COVERED WITH A FILM THAT CANNOT BE WASHED OFF FROM THIS LEAK. A RECALL SHOULD BE ISSUED FOR THIS PROBLEM, I AM NOT THE FIRST PERSON TO FILE THIS COMPLAINT ON YOUR WEBSITE. THANK YOU.*AK
Mileage: 58,000
I OWN A PREOWNED 1998 MISTUBISHI DIAMANTE LS. WHEN THE CLIMATE CONTROL, PARTICULARLY THE HEATER IS ENGAGED, THE SMELL OF ANTI-FREEZE BECOMES QUITE APPARENT. DEALER CLAIMED 2 YEARS AGO WHEN I BOUGHT IT THAT IT WAS THE SMELL OF THE CHEMICALS USED TO CLEAN THE CAR DURING "MAKE-READY." ETHYLEN GLYCOL FUMES ARE TOXIC AND THIS IS A REOCCURING DEFECT IN THIS MODEL CAR FROM POSTS I HAVE SEEN ON VARIOUS WEBSITES. I WAS LATER TOLD THAT TO FIX THIS PROBLEM WILL COST CLOSE TO $1000 SINCE THE CAR IS OUT OF WARRANTY. MITSUBISH ISSUED A TSB ADDRESSING THIS PROBLEM, OBVIOUSLY THEY ARE AWARE OF IT. IN ADDITION, THE WINDSHIELD IS COVERED WITH A FILM THAT CANNOT BE WASHED OFF FROM THIS LEAK. A RECALL SHOULD BE ISSUED FOR THIS PROBLEM, I AM NOT THE FIRST PERSON TO FILE THIS COMPLAINT ON YOUR WEBSITE. THANK YOU.*AK
Mileage: 58,000
I OWN A PREOWNED 1998 MISTUBISHI DIAMANTE LS. WHEN THE CLIMATE CONTROL, PARTICULARLY THE HEATER IS ENGAGED, THE SMELL OF ANTI-FREEZE BECOMES QUITE APPARENT. DEALER CLAIMED 2 YEARS AGO WHEN I BOUGHT IT THAT IT WAS THE SMELL OF THE CHEMICALS USED TO CLEAN THE CAR DURING "MAKE-READY." ETHYLEN GLYCOL FUMES ARE TOXIC AND THIS IS A REOCCURING DEFECT IN THIS MODEL CAR FROM POSTS I HAVE SEEN ON VARIOUS WEBSITES. I WAS LATER TOLD THAT TO FIX THIS PROBLEM WILL COST CLOSE TO $1000 SINCE THE CAR IS OUT OF WARRANTY. MITSUBISH ISSUED A TSB ADDRESSING THIS PROBLEM, OBVIOUSLY THEY ARE AWARE OF IT. IN ADDITION, THE WINDSHIELD IS COVERED WITH A FILM THAT CANNOT BE WASHED OFF FROM THIS LEAK. A RECALL SHOULD BE ISSUED FOR THIS PROBLEM, I AM NOT THE FIRST PERSON TO FILE THIS COMPLAINT ON YOUR WEBSITE. THANK YOU.*AK
Mileage: 58,000
I OWN A PREOWNED 1998 MISTUBISHI DIAMANTE LS. WHEN THE CLIMATE CONTROL, PARTICULARLY THE HEATER IS ENGAGED, THE SMELL OF ANTI-FREEZE BECOMES QUITE APPARENT. DEALER CLAIMED 2 YEARS AGO WHEN I BOUGHT IT THAT IT WAS THE SMELL OF THE CHEMICALS USED TO CLEAN THE CAR DURING "MAKE-READY." ETHYLEN GLYCOL FUMES ARE TOXIC AND THIS IS A REOCCURING DEFECT IN THIS MODEL CAR FROM POSTS I HAVE SEEN ON VARIOUS WEBSITES. I WAS LATER TOLD THAT TO FIX THIS PROBLEM WILL COST CLOSE TO $1000 SINCE THE CAR IS OUT OF WARRANTY. MITSUBISH ISSUED A TSB ADDRESSING THIS PROBLEM, OBVIOUSLY THEY ARE AWARE OF IT. IN ADDITION, THE WINDSHIELD IS COVERED WITH A FILM THAT CANNOT BE WASHED OFF FROM THIS LEAK. A RECALL SHOULD BE ISSUED FOR THIS PROBLEM, I AM NOT THE FIRST PERSON TO FILE THIS COMPLAINT ON YOUR WEBSITE. THANK YOU.*AK
Mileage: 58,000
1998 MITSUBISHI DIAMANTE. COOLANT LEAK FROM HEATER CORE O RING FAILURE. COOLANT LEAKING INTO PASSENGER COMPARTMENT CAUSING EYE AND THROAT IRRITATION, FOGGING OF WINDOWS CAUSING POOR VISIBILITY. LEAKING ONTO KEY CAR ELECTRONICS WHICH COULD CAUSE OTHER CAR COMPONENTS TO FAIL WITHOUT WARNING. HEATER CORE O RING WAS REPLACED AT 55,000 MILES AT A COST OF $560.00. NOW AT 106,000MILES LEAKING HAS STARTED AGAIN AND MITSUBISHI WANTS $650.00 TO FIX WITH NO GUARANTEE THAT FIX IS PERMANENT. *JB
Mileage: 56,231
HEATER CORE PROBLEM. WINDOWS STARTED TO FOG UP AND VERY STRONG SMOKE TYPE ORDER FROM THE VENTS. COMPUTER WAS COVERED WITH BROWN BURNT SUBSTANCE.*AK
Mileage: 52,300
THIS IS THE SECOND TIME SINCE DECEMBER 2003 THAT THE ACCELERATOR STUCK WHILE IN REVERSE AND THE BRAKES FAILED, CAUSING PROPERTY DAMAGE AND INJURIES. THIS IS VERY DANGEROUS AND I THANK GOD THAT NO LITTLE KIDS WERE KILLED!!! THE FIRST TIME IT HAPPENED I CALLED MITSUBISHI AND REPORTED THE PROBLEM AND NEVER GOT A RESPONSE.*AK
THIS IS A MITSUBISHI DIAMANTE 1998 ES. I'M EXPERIENCING PUNGENT SMELL OF ANTI-FREEZE INSIDE THE CAR AS SOON AS I TURN ON HEATING. THE DEALER I GOT THE PREOWNED CAR FROM WON'T FIX THE PROBLEM UNLESS I CAN SHOW THEM THE LEAK IN HEATER CORE. ANTI-FREEZE CONTAINS ETHYLENE GLYCON AND THE FUMES ARE HIGHLY TOXIC. FIXING THE THE HEATER CORE WILL COST $1000. 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 WIND SHIELD THUS PUTTING THE DRIVER AT GREATER RISK. I WILL EVENTUALLY FIX THE PROBLEM BY SPENDING $1000 AFTER THE SUMMER IF MITSUBISHI REFUSES TO ISSUE
Mileage: 91,000
REAR PASSENGER SIDE SHOULDER BELT BUCKLE COULD NOT BE UNLATCHED. THIS CAUSED CHILD TO BE LOCKED IN THE SEAT BELT AND UNABLE TO MOVE. SEAT BELT HAD TO BE CUT NEAR THE WAISTLINE AREA TO FREE THE CHILD. *AK *NLM
Mileage: 69,500
KUMHO 716 HP4 P215-60-16 94H DOT # 4TL1-YP71-2501 H-RATED TIRES WERE NOT THE CORRECT RATING THAT WAS SUPPOSED TO BE PUT ON VEHICLE. CONTACTED DEALER WHO WAS NOT WILLING TO DO ANYTHING.*AK CONSUMER ALSO STATES THAT CD PLAYER IS INOPERATIVE, NO RADIO CODE STORED, ARMREST COMPARTMENT HOOK LOCK BROKEN, POWER STEERING FLUID ON MINIMUM LEVEL. *TT
Data as of 2025. Sources: NHTSA Office of Defects Investigation (ODI) complaints database, NHTSA recall campaign API, NHTSA NCAP crash-test ratings, and NHTSA FARS for fatality cross-reference.
Read our methodology — how this data is sourced, computed, and verified.