1999 Mercedes-Benz ML320 Problems
- Complaints
- 125filed with NHTSA
- Median mileage
- 71,500miles, 72 complaints with mileage
- Recalls
- 0campaigns on record
- Trend
- FallingComplaints filed in the last 3 full calendar years are at least 25% lower than in 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 / 19 hwy
Sources: NHTSA records for the 1999 Mercedes-Benz ML320 (complaints, recalls, investigations), EPA fuel economy. Report an error
What owners report
Owners of the 1999 ML320 most often describe the front crankshaft pulley (harmonic balancer) coming apart and taking the serpentine belt with it, which cuts power steering and can damage the front of the engine. Power steering fluid leaks from hoses and clamps are the second recurring theme, and a smaller group describes braking or unintended-acceleration events. Many of these complaints were filed between roughly 55,000 and 110,000 miles.
- Engine cooling
Harmonic balancer / crankshaft pulley failure
- 20 complaints (16%)
- median 71,595 mi at 5.0 yrs old (18 state mileage)
- owner-quoted repair $1,500 (median of 5 quotes)
- filed 2002–2004
Owners describe a loud noise from the front of the engine followed by the belt-driven accessories stopping, so power steering assist is lost and the vehicle may stall. Complaints mention the pulley separating at its rubber bond, damaging the oil pan, front cover or timing cover, and in some cases the dealer replaced the balancer, oil pan and covers. Several owners say the dealer treated the failure as uncommon, while others report being told the part was checked shortly before it failed. Mostly reported between roughly 36,000 and 110,000 miles, sometimes without warning while driving.
What to check: Have the crankshaft pulley and its rubber bond inspected for cracks or separation, and check for oil-pan damage or a belt that has been running off-center.
2 excerpts from owner complaints in NHTSA records
“1999 mercedes ML320 harmonic balancer. I was aware of the investigation being performed and had mercedes check the balancer in january. They said it's fine. On 9/6/04, it failed causing $1500 in damage. I was not injured because I knew not to drive the vehicle after failure. Mercedes needs to recall the harmonic balancer. It is failing on most vehicles and causing extensive damage.”
NHTSA complaint #10090612, filed 2004-09, 93,000 miles“While driving a loud noise came from the front of the engine. I took the car to the dealer and the crankshft pulley has failed making a hole in the oil pan. The pulley and the oil pan were replaced and found out that this kind of premature failures has happened with this model. The dealer will not pick up the full cost for repairs since the car had 85000 miles. I think mb realizes that they have an issue with this type of failures but will not do a recall.”
NHTSA complaint #10093066, filed 2004-09, 87,000 miles - Steering
Power steering fluid leaks and loss of assist
- 24 complaints (19%)
- median 62,365 mi at 7.2 yrs old (18 state mileage)
- filed 2002–2023
Complaints describe power steering fluid leaking from the lower hose and clamp at the radiator connection, sometimes blowing the hose off and leaving steering very heavy. Owners report repeated repairs, refilling the reservoir, and puddles under the vehicle, and several mention a hose/clamp campaign being performed without ending the leak. Some complaints also describe noise or rattling from the steering column area on rough roads. Reported across a wide mileage range, from about 33,000 to over 200,000 miles, and in some cases recurring every winter.
What to check: Check the power steering reservoir level and look for wetness at the lower hose and cooler connection; ask whether the hose and clamp were replaced and whether fluid has been refilled between services.
2 excerpts from owner complaints in NHTSA records
“My pwr steering pressure hose, from bottom radiator thru pwr steering rack are four times pop out at hose clamp, every winter problem! ( 2002 ) (2003) (2004) mercedes dealer replaces a recall hose last winter & hold for a year. (2005) again winter 2 dec 05 the same thing promblem (hose pop out again) I need help to investigate this matter, pls!!! Today, I will drop off my SUV 10 dec 05 at the same dealer.”
NHTSA complaint #10144881, filed 2005-12, 58,680 miles“Reference: vehicle complaint - 47046 in september 1999, we purchased a new Mercedes-Benz, ml-320. In 2003, the vehicle was part of a recall concerning a lower power steering hose and clamp at the radiator fitting. On august 7, 2007, while driving the vehicle, the lower power steering hose blew off losing all hydraulic fluid. We lost the power steering and had extreme difficulty steering the vehicle. The same problem has occurred with a family member's ml-320. In addition, the transmission has frozen four times in first gear. …”
NHTSA complaint #10199666, filed 2007-08, 63,500 miles - Transmission and drivetrain
Harsh or delayed transmission engagement
Mentioned in 8 of 60 sampled complaints
Owners describe a hard jolt when shifting from park into drive or reverse, and transmissions that stay stuck in a low gear or refuse to shift out of park. In some complaints the vehicle started in third gear and felt sluggish pulling away, and dealers either replaced fuel-related parts or could not reproduce the problem. Mostly reported from about 33,000 to 160,000 miles.
What to check: On a cold start, shift from park to drive and reverse and note any harsh engagement; ask whether the transmission has been serviced and whether shift complaints were ever diagnosed.
2 excerpts from owner complaints in NHTSA records
“Car was in park at the top of the driveway and rolled down my driveway down a hill and crashed into a tree to stop. The car maker sent an investigator out (after a month) who determined it was a defect in the transmission. (I am awaiting their report to me) car is not drivable.”
NHTSA complaint #10023724, filed 2003-06, 153,000 miles“In september 1999, we purchased a new Mercedes-Benz, ml-320. In 2003, the vehicle was a part of a recall for a lower power steering hose and clamp at the radiator fitting. On august 7, 2007, while driving the vehicle, the lower power steering hose blew off loosing all hydraulic fluid. We lost the power steering and had extreme difficulty steering the vehicle. The same problem has occurred with a family member's ml-320. In addition, the transmission has frozen four times in first gear. The mercedes dealer was unable to locate the problem. …”
NHTSA complaint #10199413, filed 2007-08, 63,500 miles - Vehicle speed control
Sudden acceleration / throttle sticking
- 6 complaints (5%)
- median 81,780 mi at 8.5 yrs old (6 state mileage, few)
- 3 mention a crash, fire or injury
- filed 2004–2012
Complaints describe the engine revving and the vehicle accelerating without the pedal being pressed, sometimes from low speed or while parking, with owners reporting that braking did not stop it. In one account a technician identified a failed throttle cable bushing, and in another the cruise control was replaced; several owners say the dealer could not find a fault. Reported at low mileage as well as past 100,000 miles, including during parking-lot maneuvers and turns.
What to check: Ask whether the throttle cable and its bushings have been inspected, and check that the pedal and cable move freely and return without binding.
2 excerpts from owner complaints in NHTSA records
“I and my 7 year old daughter and her friend were entering my driveway on aug 14,2006, paused to open my garage door from the car and I was slowly moving in. All of a sudden car went out of my control in a flash that I did not even have time to react. It went and hit our other parked car in the garage with such a huge force that the second car literally went and tore the bedroom wall. Our second car is badly damaged on the front, back and one side (scraping a pole in garage) and wall needs fixing too. …”
NHTSA complaint #10167609, filed 2006-09, 78,446 miles“The contact owns a 1999 mercedes ML320. The contact stated that while turning a corner, the vehicle suddenly accelerated. The vehicle did not respond to the brakes and did not stop until crashing into a boulder. There were no injuries from the accident. The contact took the vehicle to an independent mechanic where the cruise control was replaced. The VIN was unavailable. The failure mileage was 144,000.”
NHTSA complaint #10424446, filed 2011-09, 144,000 miles - Brakes
Unintended braking and locked front brakes
- 11 complaints (9%)
- median 70,770 mi at 17.3 yrs old (6 state mileage, few)
- 1 mention a crash, fire or injury
- filed 2000–2020
Owners describe front brakes applying or dragging without the pedal being pressed, causing the vehicle to slow or stop and the wheel, hub and pads to get very hot and smoke. In some accounts the vehicle needed high revs and downshifting to overcome the braking force, and after cooling it behaved normally. Dealers and independent shops in the complaints often could not find a cause, while some owners point to a yaw rate sensor being replaced. Reported from about 46,000 to 140,000 miles, often in warm weather or during stop-and-go driving.
What to check: After a test drive, feel each front wheel for uneven heat and look at the pads and rotors for blueing; ask whether the yaw rate sensor or ABS-related faults have been diagnosed.
2 excerpts from owner complaints in NHTSA records
“The yaw rate sensor is causing the car to unintended breaking. It started the breaking since I purchased the car in june, however over a week ago the actual car will break while im drive and bring the car to a complete stop and will not go until I cut the car completely off and let it sit for about 10-15 min and turn it back on and then it will drive again.”
NHTSA complaint #11354739, filed 2020-09, 35 miles“Uncommanded breaking of front wheels resulted in deceleration and severe overheating of front brakes. This occurred within one mile of destination. High engine revs and downshifting of the transmission were required to overcome the uncommanded breaking force and reach the destination. A similar second occurrence effected only the right front brake.”
NHTSA complaint #10631476, filed 2014-09, 95,540 miles
Buying note. These complaints cluster around the front pulley and power steering plumbing, so a pre-purchase inspection focused on those two areas is worthwhile on a 1999 ML320. Ask for service records showing how the steering hose, pulley and brake symptoms were handled, and expect that many of these repairs are maintenance items on a vehicle of this age.
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 125 consumer complaints for the 1999 Mercedes-Benz ML320. 72 of the complaints include a mileage, and 17% of those were filed for vehicles with under 50,000 miles; the median is 71,500 miles. Of all complaints, 14 involved a crash, 2 a fire, 12 an injury, according to the filers. NHTSA lists 0 recall campaigns and 29 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 cooling35 28%
- Steering29 23%
- Fuel system14 11%
- Brakes11 8.8%
- Vehicle speed control7 5.6%
- Air bags5 4.0%
- Other or unknown5 4.0%
- Suspension5 4.0%
Also reported: Body and structure (4), Electrical system (3), Electronic stability control (3), Seat belts (3), Latches, locks and linkages (2), Equipment (1), Seats (1).
Example complaints
Engine cooling: “The harmonic balancer on my 1999 mercedes ML320 engine type m112 failed and resulted in $4,000 to repair. The part failed with no advanced warning. Even the mercedes dealership who performed the power steering recall two weeks prior to the failure did not spot any problem and they knew to be looking. I was lucky the failure occurred in my driveway backing out of the garage in stead of on the freeway with an immediate loss of power steering or destruction of the engine.”
NHTSA complaint #10045802, filed 2003-11, 70,190 milesSteering: “While driving 25 MPH, the check engine light appeared on the dashboard and remained on. The driver took the vehicle to a body shop for inspection. The driver noticed fluid leaking from underneath the vehicle. The mechanic inspected the vehicle and determined that the power steering hose needed to be replaced and replaced it. However, the problem still occurs at this time. Please provide further details.”
NHTSA complaint #10107391, filed 2005-01, 70,150 milesTransmission and drivetrain: “Consumer was able to remove the key from ignition without the vehicle being in park. The consumer stated that she could shift the gear lever to all gears when the key was not in the ignition and engine in an off position. The vehicle rolled down the hill and ran over a mailbox damaging the vehicle and back while the gear lever was still in park. The rear seat belts does not retract and had to be manually pushed back into the mechanism.”
NHTSA complaint #10099784, filed 2004-12, 78,000 milesFuel system: “1.) brake pads need replacing after 10,000 miles. 2.) fuel filter replacement requires newly designed part and additional hoses, clamps etc totaling over $300. Because previous part causes fuel leaks(?) and not available. Shouldn't mb pay for part of this??”
NHTSA complaint #10010610, filed 2003-03Mileage when problems were reported
17% of the 72 complaints with a mileage were filed for vehicles with under 50,000 miles; the middle half falls between 58,700 and 99,000 miles.
Complaints by year filed
Trend: falling. Complaints filed in the last 3 full calendar years are at least 25% lower than in the 3 years before.
Fuel economy and running cost
EPA ratings for each 1999 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 | 19 | 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 1999 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.
NHTSA investigations
- PE03006Power steering hose assembly leakageClosed · Feb 13, 2003
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. 29 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 1999 Mercedes-Benz ML320?
Owners of the 1999 ML320 most often describe the front crankshaft pulley (harmonic balancer) coming apart and taking the serpentine belt with it, which cuts power steering and can damage the front of the engine. The issues reported most often: Harmonic balancer / crankshaft pulley failure; Power steering fluid leaks and loss of assist; Harsh or delayed transmission engagement.
How many NHTSA complaints does the 1999 Mercedes-Benz ML320 have?
NHTSA recorded 125 consumer complaints for the 1999 Mercedes-Benz ML320 as of Oct 31, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.
What part of the 1999 Mercedes-Benz ML320 is reported most often?
Engine cooling is named most often, in 35 complaints (28% of the total), followed by steering with 29.
Has the 1999 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 1999 Mercedes-Benz ML320 get?
The EPA rates the 1999 Mercedes-Benz ML320 (ML320, 3.2L 6-cyl) at 17 mpg combined, 15 city and 19 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 1999 Mercedes-Benz ML320 reported?
Among the 72 complaints that include a mileage, the median is 71,500 miles and the middle half falls between 58,700 and 99,000 miles; 17% 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. 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.