1999 Mitsubishi Diamante Engine cooling Problems
- Complaints
- 3about this part
- Share
- 13%of 23 total for the year
- Median mileage
- 71,250miles
- Trend
- Not enough dataFewer than 15 complaints, too few for a reliable trend.
NHTSA recorded 3 complaints about the engine cooling of the 1999 Mitsubishi Diamante, 13% of the 23 complaints for this model year. Where a mileage was given, the median is 71,250 miles.
Fewer than 15 complaints name this part, so treat the figures as a rough indication only.
Example complaints
Selected from NHTSA records; personal details are removed. They are consumer reports, not findings.
“I started to notice an odd smell in the vehicle and noticed a lack of coolant in the reservoir tank. After a few weeks I realized there was coolant accumulating on the passenger side floorwell. 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.”
NHTSA complaint #10116609, filed 2005-04, 52,500 miles“I own a Mitsubishi Diamante, 1999. 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.”
NHTSA complaint #10408771, filed 2011-06Related service bulletins
- 10170074Aug 28, 2015This is a service newsletter (Tech Talk) that was sent out to dealers.
- 10170071Jul 22, 2015This is a service newsletter (Tech Talk) that was sent out to dealers.
- 10170086Nov 1, 2012This is a service newsletter (Tech Talk) that was sent out to dealers.
Engine cooling: other model years
| Year | Complaints | Share of year |
|---|---|---|
| 2003 | 17 | 30% |
| 2002 | 38 | 31% |
| 2001 | 14 | 18% |
| 2000 | 7 | 14% |
| 1999 | 3 | 13% |
| 1998 | 1 | 4% |
| 1997 | 4 | 12% |
| 1995 | 2 | 17% |
| 1994 | 2 | 7% |
| 1993 | 3 | 10% |
| 1992 | 11 | 26% |
Other parts of the 1999 Mitsubishi Diamante
11 complaintsBrakes
3 complaintsSuspension
3 complaintsFuel system
1 complaintsSeat belts
1 complaintsSeats
1 complaintsSteering
1 complaintsBody and structure
1 complaintsTires
1 complaints
← All problems reported for the 1999 Mitsubishi Diamante
About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Oct 30, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.
To check a specific vehicle for open recalls, use its VIN at nhtsa.gov/recalls. Methodology