1998 Mercedes-Benz ML320 Problems
- Complaints
- 133filed with NHTSA
- Median mileage
- 79,279miles, 43 complaints with mileage
- Recalls
- 0campaigns on record
- Trend
- StableComplaints filed in the last 3 full calendar years are within 25% of the 3 years before.
- NHTSA crash rating
- —overall rating starts with 2011 models
- EPA fuel economy
- 17 mpgcombined, 3.2L 6-cyl 4WD/AWD · 15 city / 20 hwy
Sources: NHTSA records for the 1998 Mercedes-Benz ML320 (complaints, recalls, investigations), NHTSA crash tests, EPA fuel economy. Report an error
What owners report
Owners of the 1998 ML320 most often report a crankshaft harmonic balancer that comes apart or loosens, taking the drive belt, power steering and charging with it. Complaints also cluster around key/immobilizer failures that leave the vehicle unable to start, fuel pump and fuel-line problems, and seat belt pretensioners that fire while the car is parked. Many reports arrive well past 70,000 miles, though belt-driven pulley and fuel-system failures also appear below that.
- Engine cooling
Crankshaft pulley (harmonic balancer) failure
- 14 complaints (11%)
- median 73,500 mi at 5.9 yrs old (13 state mileage)
- 1 mention a crash, fire or injury
- filed 2002–2007
Owners describe the crankshaft pulley or harmonic balancer separating or shattering, often without warning while driving. Because the serpentine belt drives the power steering, alternator and water pump, complaints describe sudden loss of power steering, smoke, and in some cases overheating or rapid oil loss when the pulley damages the timing cover. Dealers replaced the pulley and related parts; several owners say they received no goodwill coverage once the vehicle was out of warranty. Mostly reported between roughly 46,000 and 100,000 miles, with a few higher-mileage cases.
What to check: Ask whether the harmonic balancer and serpentine belt have been replaced, and inspect the pulley for cracks, rust or a rubber ring pulling away from the hub.
2 excerpts from owner complaints in NHTSA records
“98 mercedes ML320 with 75,000 miles harmonic balancer went up and destroyed half of the engine which cost over $5,000 in repairs. Mbusa said they had no previous complaints and that I was responsible for all repairs since it was out of warranty. I have since found out that this is a known problem for these vehicles/engines that mb is trying to cover up.”
NHTSA complaint #10041450, filed 2003-10, 75,000 miles“Harmonic balancer broke apart at 140k , no indication of failure, just lots of smoke and no steering capabilities, was in the middle of the intersection. Police pushed me to safety. Plastic shattered everywhere in engine compartment.. The defect was the plastic pully, internet research showed other people had same problem and cost them thousands.”
NHTSA complaint #10196654, filed 2007-07, 148,000 miles - Electrical system
Key not recognized, vehicle will not start
- 14 complaints (11%)
- median 102,500 mi at 9.5 yrs old (8 state mileage, few)
- owner-quoted repair $4,000 (median of 5 quotes)
- filed 1999–2014
Complaints describe the vehicle refusing to start because the key's security chip is no longer recognized, sometimes after a low battery or jump start. Owners say replacing the key is a dealer-only item with long waits, and several were quoted for re-keying the whole vehicle once the maximum number of keys had been issued. Some report the car also stalls or shuts down when the electronics cut out. Spread across the life of the vehicle, from a few years old to over 150,000 miles; several owners connect it to a weak battery.
What to check: Ask how many keys come with the vehicle and whether any have been re-programmed; have a shop confirm the engine starts reliably, both hot and cold, and that the battery is healthy.
2 excerpts from owner complaints in NHTSA records
“My battery was low and unknown to me the ML320 for this year loses its transponder codes in the das security module when you try to start the vehicle with a low battery. This is evidentally the third key that has lost its programming on my vehicle due to low battery voltage. Cost so far is 499 for a key, weeks waiting for the key from germany, and 300 to program it once they recieve the key. Its a dealership only item so its very very costly. …”
NHTSA complaint #10669353, filed 2014-12, 131,459 miles“Car fails to start. We had this car towed to a dealer 40 miles away from our daughter's school in mi. Needs new key system as chip not recognized and ignition system needs to be re-keyed. 8 keys have been issued to this car,(we bought it used). We only received 1 with our purchase! Everything that needs a key has to be changed. Cost estimated at $4000. We see this as a major design flaw, not a security benefit. Especiallly since their keys just quit working.”
NHTSA complaint #10390550, filed 2011-03, 71,000 miles - Brakes
Brake pedal to the floor / brake line corrosion
- 17 complaints (13%)
- median 59,945 mi at 6.6 yrs old (7 state mileage, few)
- 6 mention a crash, fire or injury
- filed 1998–2014
Complaints describe the brake pedal sinking to the floor with little or no stopping power, in one case traced by the dealer to a corroded rear brake line. Other owners report repeated hydraulic brake system repairs, braking problems on slippery or gravel surfaces, and a brake light warning that returns after bulb replacement. Reported from about 50,000 to 98,000 miles in the sample.
What to check: Have the brake lines inspected for rust underneath, check the brake fluid level and pedal feel, and confirm all brake lights work.
2 excerpts from owner complaints in NHTSA records
“Message display indicates left brake light not working. Replaced bulb and message disappeared for one day and then reappeared. Removed bulb and bulb was ok. Went online and found where mercedes had a brake light repair kit for this problem but I was not notified. I called the dealer and this repair kit is not under warranty or recall. …”
NHTSA complaint #10615645, filed 2014-07, 98,275 miles“My car rolled over on klondike highway in yukon, canada. It happened when driven on down slope loose gravel. The road condition was not good on that highway. When the car travel from the paved road condition to loose gravel, it slipped in the beginning then lost control and rollover. I could not stop the car by stepping hard on the brake. My wife got a broken shoulder when it rolled over. I got some cut and scratches on my right hand. The car was upside down finally. I don't think the ABS and ets kicked in at that moment. …”
NHTSA complaint #767047, filed 2002-09 - Fuel system
Fuel pump and fuel line problems
- 11 complaints (8%)
- median 39,658 mi at 4.3 yrs old (4 state mileage, few)
- 2 mention a crash, fire or injury
- filed 1999–2008
Owners report fuel pumps failing and leaving the vehicle stranded, sometimes after rough running or stalling, with dealers fitting a revised pump. Other complaints describe a fuel line at the tank working loose and spraying fuel, persistent sloshing noises from the tank, repeated fuel sender and gauge replacements, and rough running traced to fuel delivery. Reported from low mileage up to about 70,000 miles in the sample.
What to check: Ask about fuel pump and fuel sender replacement history, look for fuel smell or wet spots around the tank and lines, and note whether the fuel gauge reads steadily.
2 excerpts from owner complaints in NHTSA records
“Fuel pump failure after 70,000 miles. Left stranded on the road. Had to call for a tow truck. Hammond tire and auto center in hammond,la contacted benson mercedes in metairie and was told several of these had appeared in recent months in his shop. Benson mercedes sent out the new fuel pump with several modifications made to bring the vehicle up to compliance . …”
NHTSA complaint #10052533, filed 2004-01, 70,000 miles“Apparently, the fuel injection system on the 1998 ML320 fails quite often....even on trucks with low mileage. ***** dimsii ivoq entry posted after 12/12/02 cut-over to artemis*****731049.”
NHTSA complaint #10006347, filed 2000-09, 33,000 miles - Seat belts
Seat belt pretensioner fires unexpectedly
- 8 complaints (6%)
- median 142,900 mi at 10.5 yrs old (3 state mileage, few)
- 6 mention a crash, fire or injury
- filed 2000–2015
Several owners describe a bang, smoke and the shoulder belt suddenly pulling tight, sometimes while the vehicle is parked and the belt is fastened. Complaints say the retractor then locks or will not release, and the SRS light comes on; some report being held against the seat until the belt could be unfastened. Owners say the belts had to be replaced, and some note a past belt recall notice. Mostly reported on vehicles with 100,000 to 170,000 miles; the event is described as happening at start-up or while parked.
What to check: Pull each belt out fully and let it retract, check that the SRS light goes out after start-up, and ask whether any belt or pretensioner repairs have been done.
2 excerpts from owner complaints in NHTSA records
“After buckling the seat belt, the shoulder harness on the drivers side exploded. The harness yanjed me back against the seat burning my shoulder and the car filled with smoke. The car is a 1998 mercedes benz ML320. If I had been on the road when this happened, it would have caused an accident. Are there any other reports of this happening?”
NHTSA complaint #10028813, filed 2003-07“I put my seat belt (s/b) on and started the ignition. A loud bang, I was jerked back into my seat by the s/b and was trapped. White smoke escaped where the s/b comes out of the frame. The srs light was illuminated. I turned the car off, unbuckled the s/b, which didn't retract back into the feed, got out of the car and waited for the smoke to dissipate. I got back into the car, put my s/b on, which was stuck and would not adjust. I called mb dealership to report incid and make apt for car to be chkd. 8-30-07 I brought car into mb of reno, nv. …”
NHTSA complaint #10203560, filed 2007-09, 97,433 miles
Buying note. A pre-purchase inspection focused on the crank pulley and belt drive, the brake and fuel lines, and the seat belts will tell you more than the mileage alone. Ask for service records covering the harmonic balancer, fuel pump and any key or immobilizer work, since those jobs are the ones owners most often describe paying for themselves.
Summary written with AI from a sample of 60 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.
NHTSA recorded 133 consumer complaints for the 1998 Mercedes-Benz ML320. 43 of the complaints include a mileage, and 19% of those were filed for vehicles with under 50,000 miles; the median is 79,279 miles. Of all complaints, 9 involved a crash, 5 a fire, 16 an injury, according to the filers. NHTSA lists 0 recall campaigns and 28 technical service bulletins for this model year.
Not compared (before 2008). Model years 2008–2023 of the same vehicle that have at least 25 complaints are compared, and a model needs at least 3 of them.
Which parts are reported most
Complaints can name more than one part, so the counts add up to more than the total. Select a part to see its complaints, recalls and bulletins.
- Engine cooling31 23%
- Electrical system21 16%
- Fuel system20 15%
- Brakes16 12%
- Body and structure12 9.0%
- Transmission and drivetrain10 7.5%
- Seat belts8 6.0%
- Air bags7 5.3%
- Vehicle speed control7 5.3%
Also reported: Steering (6), Equipment (5), Exterior lighting (5), Other or unknown (5), Suspension (5), Seats (4), Latches, locks and linkages (3), Wheels (3), Interior lighting (2), Engine (1).
Example complaints
Engine cooling: “While driving in traffic, the vehicle seems to be leaking exhaust directly into the passenger compartment causing me to have severe headaches and feel very tired. It helps somewhat with the odor when the HVAC is switched to recirculate, but I feel that co is still seeping in the vehicle.”
NHTSA complaint #10150915, filed 2006-02, 139,000 milesElectrical system: “On my mercedes ML320, 1998 the key refuse to start the engine. I was told at plaza motors in st,. Louis mo. That the car did not recognize the key any more. Upon my research I found that it is common problem with the ML320 series which is an engineering problem on the part of the manufacturer especially the earlier once 1998-2000 and it will cause $6700.00 to fix. I will appreciate an investigation, it's so common that a lot of people are selling their cars because of this.”
NHTSA complaint #10236339, filed 2008-07, 125,000 milesFuel system: “Laundry list of failures. Jack has almost killed me while changing tire. Vehicle fell, almost hitting me but catching side of vehicle before landing on me! Hood latch has failed on a few occasions, causing hood to open while vehicle was in motion. Air mass meter failed. Has required 5 (five!) alignments in two years. When brought to dealer's attention, was told nothing was wrong. A month later requires another alignment. Alignment problems causes wear on tires, which has caused hydroplaning and loss of control of vehicle. Vehicle swerves uncontrollably when hits anything other than flat road. …”
NHTSA complaint #10068171, filed 2004-05, 97,615 milesVisibility (wipers, defrost, mirrors): “In temperatures below 20 degrees the windshield washer fluid freezes up, even with de-icer additive added to the system. When dirt is kicked up from a preceding automobile, you cannot clean off the windows, this leads to impossible visibility. Pulling off the road every 5 minutes to rectify this problem is not always easy to do. I'm 5ft. And its also hard to reach the window to clean it off. Several calls were placed for assistance, but I was told that the nozzles are not heated and not protected to keep the component parts from freezing. …”
NHTSA complaint #717810, filed 2000-01Mileage when problems were reported
19% of the 43 complaints with a mileage were filed for vehicles with under 50,000 miles; the middle half falls between 56,700 and 131,459 miles.
Complaints by year filed
Trend: stable. Complaints filed in the last 3 full calendar years are within 25% of the 3 years before.
Crash test ratings
NHTSA's 5-Star Safety Ratings for the 1998 Mercedes-Benz ML320. Frontal results are shown driver / passenger; rollover shows the star rating and NHTSA's estimated risk of rolling over in a single-vehicle crash.
| Version | Overall | Frontal | Side | Side pole | Rollover |
|---|---|---|---|---|---|
| ML-Class · sedan AWD | not rated | 4 / 5 | — | — | — |
Ratings before the 2011 model year come from an older, less demanding test and are not comparable with ratings for 2011 and later.
Source: NHTSA New Car Assessment Program (5-Star Safety Ratings), nhtsa.gov/ratings.
Fuel economy and running cost
EPA ratings for each 1998 Mercedes-Benz ML320 version. Annual fuel cost is the EPA's estimate at its current fuel prices for 15,000 miles a year (55% city driving).
| Version | Engine | Transmission | City | Hwy | Comb. | Fuel / yr |
|---|---|---|---|---|---|---|
| ML320 4WD/AWD | 3.2L 6-cyl | 5-speed automatic | 15 | 20 | 17 | $4,850 |
Source: U.S. EPA and Department of Energy, fueleconomy.gov. Ratings are for comparing vehicles; real-world mileage varies with driving and conditions.
Recalls and investigations
NHTSA lists no recall campaigns for the 1998 Mercedes-Benz ML320 in the data used here. A recall can apply to some vehicles of a model year and not others, so check a specific vehicle by VIN at nhtsa.gov/recalls.
Technical service bulletins
TSBs are manufacturer notes to dealers about known repair procedures. They are not recalls and do not by themselves mean a vehicle has a fault. 28 on record; the latest 10 are shown.
- 10181124Sep 30, 2020Transmission and drivetrain. Harsh engagement when changing gear range from P to D or R
- 10181123Sep 22, 2020Transmission and drivetrain. Harsh engagement when changing gear range from P to D
- 10135598Mar 25, 2015Engine. Engine diagnosis warning lamp lights up in instrument cluster, fault code U145400: "Implausible data were received from the ethanol sensor"
- 10166976Feb 3, 2014Equipment. Message in instrument cluster "DISTRONIC PLUSCurrently Unavailable - See Owner's Manual"
- 10166990Dec 4, 2013Suspension. Thumping noises from front axle when driving over bumps on road.
- 10167577Jul 23, 2013Visibility (wipers, defrost, mirrors). Since 12/2012 (model 166) and since 06/2013 (model 242) the glass breakage loops are no longer in the side windows and rear window. Suitable interior protection ensures that the interior monitoring…
- 10167564Jul 12, 2013Electrical system. Customer experiences low battery conditions, resulting in jump starts, and eventually requiring battery replacement.
- 10167563Jul 8, 2013Electrical system. The COMAND unit does not start or the COMAND display remains dark. The COMAND unit cannot be operated. Note: The problem disappears after a lengthy idle period (>6h) or after interrupting the power…
- 10167553Jul 1, 2013Fuel system. Combination message: "Clean fuel filter" is displayed. The fault code 162500 (water level message - Bosch) or P226997 (water level message - Delphi) or 171600 (filter load - Bosch) is stored in the…
- 10033074May 1, 2013Body and structure. Xentry: outside door handle no longer returns to end position. Due to a bent pin in the dynamic balancer, the support spring of the bearing bracket can slide out of place or become unhooked. Models…
Other model years of the Mercedes-Benz ML320
| Year | Complaints | Median mi | Recalls | Crash ★ | MPG | Score (50 = typical) | Trend |
|---|---|---|---|---|---|---|---|
| 2009 | 28 | 54,000 | 3 | — | — | Not compared (fewer than 3 comparable model years) | Falling |
| 2008 | 21 | 94,500 | 2 | — | 21 | — | Falling |
| 2007 | 16 | 43,000 | 2 | — | 21 | — | Falling |
| 2005 | 5 | 5,000 | 0 | — | — | — | Not enough data |
| 2003 | 22 | 51,723 | 0 | — | 15 | — | Stable |
| 2002 | 88 | 89,670 | 1 | — | 15 | Not compared (before 2008) | Falling |
| 2001 | 136 | 87,800 | 0 | — | 17 | Not compared (before 2008) | Falling |
| 2000 | 166 | 77,000 | 0 | — | 16 | Not compared (before 2008) | Falling |
| 1999 | 125 | 71,500 | 0 | — | 17 | Not compared (before 2008) | Falling |
| 1998 | 133 | 79,279 | 0 | — | 17 | Not compared (before 2008) | Stable |
All Mercedes-Benz ML320 model years · Best and worst years by complaints
Frequently asked questions
What are the most common problems with the 1998 Mercedes-Benz ML320?
Owners of the 1998 ML320 most often report a crankshaft harmonic balancer that comes apart or loosens, taking the drive belt, power steering and charging with it. The issues reported most often: Crankshaft pulley (harmonic balancer) failure; Key not recognized, vehicle will not start; Brake pedal to the floor / brake line corrosion.
How many NHTSA complaints does the 1998 Mercedes-Benz ML320 have?
NHTSA recorded 133 consumer complaints for the 1998 Mercedes-Benz ML320 as of Oct 31, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.
What part of the 1998 Mercedes-Benz ML320 is reported most often?
Engine cooling is named most often, in 31 complaints (23% of the total), followed by electrical system with 21.
Has the 1998 Mercedes-Benz ML320 been recalled?
NHTSA lists no recall campaigns for this model year in the data used here. To check a specific vehicle, enter its VIN at nhtsa.gov/recalls.
What gas mileage does the 1998 Mercedes-Benz ML320 get?
The EPA rates the 1998 Mercedes-Benz ML320 (ML320, 3.2L 6-cyl) at 17 mpg combined, 15 city and 20 highway, with an estimated annual fuel cost of $4,850 at 15,000 miles a year. Other engine and drive versions are rated differently.
At what mileage are problems with the 1998 Mercedes-Benz ML320 reported?
Among the 43 complaints that include a mileage, the median is 79,279 miles and the middle half falls between 56,700 and 131,459 miles; 19% were filed for vehicles with under 50,000 miles.
About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Oct 31, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate. Crash ratings are from NHTSA’s New Car Assessment Program. Fuel economy is from the EPA and DOE (fueleconomy.gov).
Complaint counts come from NHTSA’s public complaint database; we count each complaint once. The source records for this vehicle are on nhtsa.gov. Scores and trends are our own summaries of that data, described in the methodology. This page is not legal, safety or repair advice: for a specific vehicle, check its VIN at nhtsa.gov/recalls and ask a qualified mechanic. See an error? Tell us.