Problems · NHTSA complaints
1998 Mitsubishi Diamante problems
Owners filed 27 complaints about the 1998 Mitsubishi Diamante with NHTSA between Mar 1999 and May 2015. The most-cited component is visibility (15).
Complaints
27
Filed with NHTSA
Crashes
1
Reported by owners
Fires
0
Reported by owners
Injuries
4
People reported injured
Deaths
0
Reported to NHTSA
Complaints by component
One complaint can cite several components
- Visibility15
- Vehicle speed control3
- Service brakes, hydraulic3
- Electrical system2
- Visibility/wiper1
- Engine and engine cooling1
- Seat belts1
- Steering1
- Structure1
- Tires1
- Equipment1
- Wheels1
- Other / unknown1
Complaints are unverified owner reports to NHTSA and are not normalized for sales volume. One complaint can cite several components.
Data from NHTSA Complaints API · synced Oct 28, 2026NHTSA vehicle page
When complaints were filed
Does it get worse with age? Complaints per calendar year filed
3
2
6
1
1
5
2
2
1
3
0
0
0
0
0
0
1
View as table
| Model year | Complaints filed per calendar year |
|---|---|
| 1999 | 3 |
| 2000 | 2 |
| 2001 | 6 |
| 2002 | 1 |
| 2003 | 1 |
| 2004 | 5 |
| 2005 | 2 |
| 2006 | 2 |
| 2007 | 1 |
| 2008 | 3 |
| 2009 | 0 |
| 2010 | 0 |
| 2011 | 0 |
| 2012 | 0 |
| 2013 | 0 |
| 2014 | 0 |
| 2015 | 1 |
Mileage at failure isn’t a structured field in NHTSA complaint data, so we don’t chart it. Some owners mention it in their reports below.
Top problems in owners’ words
Verbatim from NHTSA complaints, newest first
Visibility
15 reports
“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”
Vehicle speed control
3 reports1 crash
“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”
Service brakes, hydraulic
3 reports
“BRAKE PADS PREMATURE WEAR, AND BRAKE ROTORS HAVE WARPED AT LEAST 10 TIMES. *AK”
Electrical system
2 reports
“WILL NOT PASS EMISSION THERE ARE NO READINESS CODES STORED IN COMPUTER. *TR”
Visibility/wiper
1 report
“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”
Engine and engine cooling
1 report
“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”
Data from NHTSA Complaints API (owner reports, unverified) · synced Oct 28, 2026
Complaints are unverified owner reports to NHTSA and are not normalized for sales volume. One complaint can cite several components.