AI Damage1999 Mitsubishi Diamante: common problems
Owners of the 1999 Mitsubishi Diamante filed 23 complaints with NHTSA, most often about visibility and engine and cooling. Details by component below, with sources.
Key figures
- Owner complaints
- 23
What fails most often
- 1 Visibility 48% of all complaints
- 2 Engine and cooling 13% of all complaints
- 3 Service brakes 13% of all complaints
- 4 Suspension 13% of all complaints
- 5 Fuel system 4% of all complaints
- 6 Seat belts 4% of all complaints
- 7 Seats 4% of all complaints
- 8 Steering 4% of all complaints
- Visibility: 11 complaints (48% of all).
- Engine and cooling: 3 complaints (13% of all).
- Service brakes: 3 complaints (13% of all).
- Suspension: 3 complaints (13% of all).
- Fuel system: 1 complaints (4% of all).
Engines and transmissions
US-market versions per EPA. On the right: how many NHTSA complaints name this engine or transmission type.
- 3.5 L · petrol · 6 cyl
- automatic, 4-speed
Drive: FWD
Symptoms owners describe
How many of the 23 NHTSA complaints mention each symptom (automatic count from complaint text; one complaint can mention several).
Components owners complain about
| Component | Owner complaints | involving a crash | Technical service bulletins (TSB) |
|---|---|---|---|
| Visibility | 11 | 0 | 0 |
| Engine and cooling | 3 | 0 | 0 |
| Service brakes | 3 | 0 | 0 |
| Suspension | 3 | 0 | 0 |
| Fuel system | 1 | 0 | 0 |
| Seat belts | 1 | 0 | 0 |
| Seats | 1 | 0 | 0 |
| Steering | 1 | 0 | 0 |
| Structure | 1 | 0 | 0 |
| Tires | 1 | 0 | 0 |
What owners report
Short excerpts of NHTSA complaints in the original wording. These are owner statements not verified by NHTSA; personal data removed.
I noticed fumes covering the passenger side windshield. In the winter time the problem is worse and it covers both passenger side and driver's side creating very dangerous driving conditions.
Rear end unstable. Vehicle backend swerves and fishtails on wet or icy surfaces. Repair shop states back end is frozen and unable to align rear tires causing vehicle to swerve when driven on wet or icy surfaces. Misalignment of rear results in new tires having to be purchased approximately every 2-3 months.
The contact stated that while traveling at various speeds the rear view mirror would shake; and was not securely attached to the windshield. The vehicle was taken to an authorized dealer who stated that the rear view mirror was attached properly.
1999 mitsubishi diamante. Consumer states that thread patterns on tires on vehicle are asymmetric. The consumer stated the tires didn't have any tread wear, or other ratings on them. The consumer was told the tires were mounted correctly. Updated 04/14/10.
The windows fog up so bad that it becomes hard to see. The vents spew out the pungent smell of anti-freeze. I have noticed on more than a few occasions that puffs of vapor shoot out from under the passenger side dash and vents.
1999 diamante engine blew three weeks after purchase.
My wife was driving the vehicle last week and noticed that the windows of the car started to fog up. The fogging became so thick that she had to pull over (blindly) and frantically wipe the window clean in order to see out of the car.
My vehicle is at 53,500 miles and was diagnosed by the dealer as having a "heater core failure." the estimate they gave is $1,300 to repair. I cannot afford it so it looks like my vehicle will be garaged until a recall is issued.
When owners complained
NHTSA complaints by filing year. The peak shows at what age the problems show up most.
Comparison
By complaint count this model year ranks 7,735 of 36,656 model years in the NHTSA data (top 21% most complained about).
On average one model year of the Diamante has 42 complaints (12 years in the data). This year has 23, below average.
What to check before buying
- Visibility. Wipers, mirrors, defrosters, cracked glass.
- Engine and cooling. Radiator and fan after a frontal hit, coolant level and condition, overheating.
- Service brakes. Pedal feel, ABS operation, leaks, discs and hoses.
- Suspension. Wheel alignment, control arms, subframe, even tire wear.
Other years of this model
Questions and answers
What are the most common problems with the 1999 Mitsubishi Diamante?
Owner complaints to NHTSA most often mention: visibility, engine and cooling, service brakes. Total complaints: 23. The most frequent symptoms in complaint texts: A/C or heater (35%), windows, sunroof (22%), engine failure or replacement (4%).
How many service bulletins (TSB) were issued for the 1999 Mitsubishi Diamante?
NHTSA lists 0 manufacturer service bulletins for this year. A bulletin tells dealers how to diagnose or fix a known issue; it is not a recall.
Should I buy a 1999 Mitsubishi Diamante from a US auction?
Owner complaints describe defects, not crash damage. Before bidding, check the components listed above and review the lot photos: VinWind builds a report of visible and hidden damage by VIN.
Other 1999 models
Read also
Sources: public NHTSA data (USA): service bulletins and owner complaints; YouTube: links to videos credited to their authors. Complaints are owner statements not verified by NHTSA, and describe defects rather than crash damage. Data updated 2026-11-05.