Which parts fail
Components named in complaints (fuel pump, injectors, fuel tank, hybrid and EV propulsion).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 1998 Mercedes-Benz ML320 owners, lightly cleaned up (personal details are redacted by NHTSA).
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. Transfer case motor fixed by dealer without consulting. After repair, transfer case motor failed. Dealer states owner responsible for costs. Has had repair of harmonic balancer on front of engine due to excessive heat buildup leading to oil leak and failure of belt tensioner. …
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. This is a known problem with mercades and checking the forums it seems that everyone that has 1998-2000 model mercades all lose their transponder codes between 129,000 and 132,000 miles no matter what.this is an obvious manufacturers defect and a known issue that should be paid for by mercades. I never had these issues with my two 2002 ml500's but I will never purchase another Benz in my life.
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". I contacted Mercedes and was told there was no recall and there would be no reimbursement for half the cost of the parts since I did not have the work done at a certified Mercedes dealership. I explained to them that it would have cost me approximately $200 to have it towed to metarie or baton rouge.
Key lock problems, would not start due to key problems, would not start because of fuel pump failures, would not start due to gas tank problems, door lock assemblies move up and down by themselves, latch on hatch door rattled, rear seat belts rattle, oil out light came on at random times, engine check light on, last the fly-by wire gas pedal went to the floor with sudden acceleration causing an accident of the vehicle with $14,000 damage.
ML320 fuel pump failed, causing crash into other vehicle. Mbz roadside assistance was called twice and claimed no record of 1st call 4 hours earlier. Vehicle was towed at owner's expense to dealer who claimed starmark warranty was expired, contrary to same dealer representation at sale.
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.
As told by the Mercedes Benz company, the fuel line and fuel filter on this particualer model, are much too small to ensure adequate fuel to the engine while driving. Dealership refused to change the line and filter while under warranty claiming it would be changed at the 60,000 mile service check up at owners expense.
1998 Mercedes Benz ML320: persistent sloshing sound coming from underbody of car. Presumed to be gas sloshing around in the tank, or some other drainage problem. Mb took two seconds to investigate by rocking the car and found nothing.
Fuel line coming out of gas tank came loose and sprayed raw fuel all over back of car and onto street. Could have ignited from any spark or open flame.
Replacement of 10 full sender and fuel gauge related equipment parts on 1998 mb ML320, replacement of transfer case.
Fuel System complaints in other ML320 years
Frequently asked questions
How common are fuel system problems on the 1998 Mercedes-Benz ML320?
NHTSA has 20 complaints about the fuel & propulsion system of the 1998 Mercedes-Benz ML320, 15% of the model year's 133 complaints. The component named most often is delivery › fuel pump (6 mentions).
Is there a recall for 1998 Mercedes-Benz ML320 fuel system problems?
No. NHTSA lists no fuel & propulsion system recall for the 1998 Mercedes-Benz ML320. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 1998 Mercedes-Benz ML320 fuel system problems start?
Half of the complaints with a recorded mileage happened before about 70,000 miles, and 17% before 25,000 miles.
Is it dangerous?
Owners linked 2 crashes, 0 fires and 1 injury to fuel & propulsion system problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.