1998 Mitsubishi Diamante problems & reliability
27 owner complaints filed with NHTSA for the 1998 Mitsubishi Diamante, alongside 1 safety recall campaign. Last verified Aug 7, 2026. Complaints are unverified reports submitted by owners to the federal Office of Defects Investigation.
Each complaint is counted once (by NHTSA case number), even when it names several vehicles.
2 complaints report injuries (4 injured).
Most reported problems
| Component | Complaints | Share |
|---|---|---|
| Visibility → | 15 | 56% |
| Service Brakes, Hydraulic | 3 | 11% |
| Vehicle Speed Control | 3 | 11% |
| Electrical System | 2 | 7% |
| Engine and Engine Cooling | 1 | 4% |
| Equipment | 1 | 4% |
| Seat Belts | 1 | 4% |
| Steering | 1 | 4% |
| Structure | 1 | 4% |
| Tires | 1 | 4% |
Component groups as classified by NHTSA. A complaint can name more than one component, so shares may sum to more than 100%.
All 13 reported components →Complaints by incident year
What owners 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…”
Visibility/wiper · filed May 11, 2015
“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…”
Vehicle Speed Control · filed Sep 28, 2008
“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…”
Visibility · filed Sep 17, 2008
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Technical service bulletins
51 manufacturer communications (TSBs, service campaigns, warranty extensions) are on file with NHTSA for the 1998 Mitsubishi Diamante. The 10 most recent:
This Technical Service Bulletin was sent to dealers to explain the difference between normal dew condensation, which is a natural phenomenon, and water penetration caused by improper sealing or a defective/broken part.
TSB-22-54-003 · Service Bulletin/Repair Instructions · issued Apr 7, 2022
This is a service newsletter (Tech Talk) that was sent out to dealers.
TT253 · Service Bulletin/Repair Instructions · issued Nov 26, 2019
This is a Technical Service Bulletin sent to dealers. This bulletin supersedes TSB-18-00-003, issued April, 2018, to add updated information for Carrying Capacity Reduced Label.
TSB-19-00-008 · Service Bulletin/Repair Instructions · issued Jul 30, 2019
This is a service newsletter (Tech Talk) that was sent out to dealers.
TT237 · Service Bulletin/Repair Instructions · issued Feb 26, 2018
This is a service newsletter (Tech Talk) that was sent out to dealers.
TT218 · Service Bulletin/Repair Instructions · issued Aug 28, 2015
This TSB contains troubleshooting steps for diagnosis of various customer complaints relating to the audio system speakers in Mitsubishi vehicles equipped with original equipment audio components.
TSB-15-54-004 · Service Bulletin/Repair Instructions · issued Jul 29, 2015
This is a service newsletter (Tech Talk) that was sent out to dealers.
TT217 · Service Bulletin/Repair Instructions · issued Jul 22, 2015
This is an index of Tech Talk newsletter articles released in 2012.
TTIndex12 · Service Bulletin/Repair Instructions · issued Mar 5, 2013
This is a service newsletter (Tech Talk) that was sent out to dealers.
TT195 · Service Bulletin/Repair Instructions · issued Mar 5, 2013
This is a service newsletter (Tech Talk) that was sent out to dealers.
TT194 · Service Bulletin/Repair Instructions · issued Feb 6, 2013
TSBs are repair guidance manufacturers send to dealers — they are not recalls and repairs are not automatically free. Full documents are available on NHTSA’s site.
Safety recalls
The 1998 Mitsubishi Diamante has 1 NHTSA recall campaign — recall repairs are free at franchised dealers regardless of the vehicle’s age.
Check whether your specific vehicle is affected
Recall campaigns often cover only certain VIN ranges. Enter your VIN on the official NHTSA site to confirm whether your vehicle is included and whether the repair is still open.
Check VIN on NHTSA →Buying a used 1998 Mitsubishi Diamante?
- · Decode the seller’s VIN with our free VIN decoder to confirm the exact year, engine and trim.
- · Check for unrepaired recalls by VIN on NHTSA’s official lookup — recall repairs are free.