10.0

really awful
Crashes / Fires:
0 / 0
Injuries / Deaths:
3 / 0
Average Mileage:
45,918 miles

About These NHTSA Complaints:

The NHTSA is the US gov't agency tasked with vehicle safety. Complaints can be spread across multiple & redundant categories, & are not organized by problem. See the Back button — blue bar at the very top of the page — to explore more.

Get notified about new defects, investigations, recalls & lawsuits for the 2001 Mitsubishi Diamante:

Unsubscribe any time. We don't sell/share your email.

problem #51

Mar 102008

Diamante

  • miles
Windows are fogging up do T a faulty heater core. I really don't mind repairing the car seeing that it has 120K on it.. I purchased the car brand new and this will be the 3rd heater core!!! what's going on!

- Brooklyn, NY, USA

problem #50

Oct 012007

Diamante

  • 75,000 miles
Mitsubishi Diamante infamous heater core problem antifreeze leaks into interior of car. Horrible sickening anti freeze smell, happens on an abundance of Mitsubishi cars.

- Rixeyville, VA, USA

problem #49

Mar 252008

Diamante

  • Automatic transmission
  • miles
Heater core is causing the windows to fog up, the car to smell like antifreeze and may be damaging the ECU. There are hundreds of posts online about people having this problem over and over with this car. It is clearly a manufacturers defect and customers are left paying thousands of dollars fo the repair.

- Champaign, IL, USA

problem #48

Mar 142008

Diamante 6-cyl

  • Automatic transmission
  • 104,000 miles
Heater core went bad at 105,000 miles. This seems to be a manufactoring problem and mitsubihi should adress the issue.

- Fontana, CA, USA

problem #47

Oct 012007

Diamante 6-cyl

  • Automatic transmission
  • miles
My 2001 Mitsubishi Diamante's heater core went up. I have massive amounts of coolant leaking on my passenger side, thick smoke coming from my vents and a bad odor coming from the vents. I have read this is a very very common thing with Mitsubishi's especially Diamante's.

- Edgewood, MD, USA

problem #46

Nov 232007

Diamante 6-cyl

  • Automatic transmission
  • 81,000 miles
Just recently started having really foggy windows and started to notice sweet smell coming from car when heater/defrost was turned on. Notified dealer of problem and dealer quickly identified problem as heater core defect.

- Ogden, UT, USA

problem #45

Nov 122007

Diamante 6-cyl

  • Automatic transmission
  • 65,000 miles
The contact owns a 2001 Mitsubishi Diamante. The windows fogged up when the air and heat were activated. The passengers could smell antifreeze. The dealer stated that the heater core failed due to defective O-rings. The heater core was replaced. The current and failure mileages were 65,000.

- San Luis Obispo , CA, USA

problem #44

Feb 222007

Diamante 6-cyl

  • Automatic transmission
  • 70,000 miles
The contact owns a 2001 Mitsubishi Diamante. The windows fogged up when the air and heat were activated. The passengers could smell antifreeze. The dealer stated that the heater core failed due to defective O-rings and noticed antifreeze leaking onto the micro processor. The micro processor and heater core were replaced. The failure mileage was 70,000 and current mileage was 75,000.

- San Luis Obispo, CA, USA

problem #43

Aug 192007

Diamante 6-cyl

  • Automatic transmission
  • 84,560 miles
2001 Mitsubishi Diamante - have antifreeze odor coming from ac vents. After much research I find that this is a recurring problem with second generation Diamantes (1997-2004) with the 2001 year model being the most effected. The odors have even caused respiratory problems. I myself have experienced severe headaches and sleepiness due to this problem. The odor at first was very faint but became worse over time. With as many problems that has occurred and the health implications related to this obvious defect, this problem should be a manufacturers recall to resolve this potentially dangerous and health hazardous issue.

- Citrus Heights, CA, USA

problem #42

May 032007

Diamante 6-cyl

  • Automatic transmission
  • 64,000 miles
I have a 2001 Mitsubishi Diamante ls with 66,000 mile and my heater core went out. I noticed my window would fog up and you can smell antifreeze in the car, to have this replaced is going to cost me almost $998 for part and labor. Most mechanics I have talked to about this problem said that I shouldn't be having this problem with the heater core so early. I know of numerous complaints of this defect for this (none of which I knew about before I bought the car) I know that it is dangerous for the antifreeze to be inhaled, and with all the complaints about this obvious defect something should be done about it. There is health risks with the heater core going out and releasing the antifreeze not to mention the safety concerns with the heater core being so near important computer components.

- Chipley, FL, USA

problem #41

Apr 252007

Diamante 6-cyl

  • Automatic transmission
  • 58,100 miles
For no particular reason my car fills up with the smell of anti-freeze coolant when I turn on the heater. I have read that this is caused by leaking 0-rings and that this will damage the computers which are underneath the leak. The car is a 2001 Mitsubishi Diamante L.S. the dealer says it is not a common issue. Google says otherwise.

- Venice , FL, USA

problem #40

Feb 192005

Diamante 6-cyl

  • Automatic transmission
  • 50,000 miles
My windshield was fogging up creating a safety hazard. I had to replace the heater core. Cost was approximately $500.

- Westport, MA, USA

problem #39

Mar 312007

Diamante 6-cyl

  • Automatic transmission
  • 80,800 miles
When using the defroster the windows increasingly fog up and it does not clear. From investigating I have come to find out that this issue appears to be caused by a documented problem with the heater core of this model of of vehicle, 2001 Mitsubishi Diamante, in this case. I purchased the vehicle used from a local dealer approximately two weeks ago. I guess lucky for us the weather turned cold, forcing us to use the defroster, and thereby discovering this problem. I realize I most likely do not have any recourse in my case I want to file this on behalf of those who might since, as stated above, this is a known issue with the Diamante.

- Rogers, AR, USA

problem #38

Jan 312007

Diamante

  • miles
Defroster would not defrost the windows. The transmission keeps going in and out of gear. Was told the heater core has gone bad, which the transmission was going in and out because coolant was dripping on the relay that was underneath it. It is going to cost $500 dollars for the relay, the reset of the check engine and heater core. Then a additional $600 dollars for labor since they have to remove the entire dashboard.

- Columbia, MO, USA

problem #37

Jan 242007

Diamante 6-cyl

  • Automatic transmission
  • 75,000 miles
Anti freeze odor is overwhelming in the car, especially when the heater is run. I have had the car since it was new, and had the same problem after only a couple of months. The dealership fixed the issue by installing a new gasket, but the fix has lasted only a couple of years. My wife and I have been having a variety of respiratory illnesses recently, and I believe these fumes are a contributing factor.

- Ft Thomas, KY, USA

problem #36

Dec 142006

Diamante

  • miles
2001 Mitsubishi Diamante with 44K miles - heater core failed and a few weeks later the transmission control device failed. This is due to leaking fluid from the heater core directly onto a computer component that has no cover. This vehicle should be recalled and Mitsubishi should pay for the repairs (about $2000).

- Portland, OR, USA

problem #35

Aug 242006

Diamante

  • miles
Recently purchased a 2001 Mitsubishi Diamante with 62K miles. Admittedly, I am not car "savvy" related to the well being of the car. When purchased, the car had a "maple syrup" type smell. Also, the windows fogged up very quickly and eventually I realized the heat took a long time to warm up. As I purchased the car in the summer, the fogging and heat problem was not noticed for two months. I have now realized that the problem has to do with the heater core. I have talked to people who are car "savy" and they say cars shouldn't have problems with a heater core until late in their lives (above 120K miles), if ever. As I discovered my problem, I realize that I have been inhaling anti freeze gas through the heat vents. I'm worried that I will have respiratory problems because of this. Has Mitsubishi taken responsibility for this severe mishap" I have researched and found that this is an extremely prevalent problem in most Diamantes. Not only is this extremely detrimental to ones health, it's an expensive fix. Is there any hope for a recall here"

- Raleigh, NC, USA

problem #34

Feb 012006

Diamante 6-cyl

  • Automatic transmission
  • 86,300 miles
: the contact stated while driving an odor of antifreeze entered the vehicle and the window were fogging up. The vehicle was taken to the dealership for inspection. The dealership replaced the heater core O-rings. The manufacturer was not alerted. Updated 3/28/2006 -

- Middletown, NY, USA

problem #33

Feb 202005

Diamante 6-cyl

  • Automatic transmission
  • 40,500 miles
At approximately 40,000 miles, my 2001 Mitsubishi Diamante heater core started leaking. The first indication was that the windshield started fogging up immediately. This was in the winter (February, Minnesota) and the defroster made it worse, driving was difficult at best. I was lucky in that I was close to home. Had I been on the freeway, it could have been more dangerous. A call to one of the local dealers informed me that the cost for the fix was over $1000. Research that I did on the internet showed that this was a very common failure and that most dealerships prefer to charge the customer outrageous bills for fixing what is obviously a manufacturing defect. Not being able to afford a bill of this size, I found a way to fix the problem myself, but it was not easy. I've found Mitsubishi is not easy to deal with. My guess is that because they no longer sell this model, they will take advantage of customers that are owners of the Diamante. I will never buy another car from this manufacturer.

- Winona, MN, USA

problem #32

Jan 252006

Diamante 4-cyl

  • Automatic transmission
  • miles
We noticed black residue on the rear windshield of 2001 Diamante. The next day when the defroster was turned on black smoke filled the inside of the car. The following day black smoke filled the car without the defroster being on. Had the car towed, and they told us it was the heater core having a hole in it. They had another 2001 Diamante sitting there with the exact same problem. Since it wasn't under warranty, we bought it certified in December, it will cost approximately $875 to fix it.

- Indianapolis, IN, USA

Read the next 20 complaints »