Verdict · NHTSA data
One of the years to avoid
With 32 complaints filed to NHTSA — about 4.6 times the median 300 year — the 1991 model ranks #3 of 23 300 years for complaint volume. It lands on the years-to-avoid list.
No single system dominates the record — complaints spread across transmission (7), engine (5), and airbags (4), which usually points to general build quality rather than one defect.
32
NHTSA complaints
2
Recalls
0
Investigations
3
Crash-involved
3
Fires reported
4
Injuries
0
Deaths
—
NCAP overall
| Component | Complaints | Share | vs prior year |
|---|---|---|---|
| Transmission | 7 | 22% | ▲ up |
| Engine | 5 | 16% | ▲ up |
| Airbags | 4 | 13% | ▲ up |
| Electrical System | 3 | 9% | ▲ up |
| Steering | 3 | 9% | ▲ up |
| Brakes | 3 | 9% | ▲ up |
| Speed Control | 2 | 6% | — flat |
| Seats | 1 | 3% | — flat |
| Tires & Wheels | 1 | 3% | ▼ down |
| Body & Structure | 1 | 3% | — flat |
| Fuel System | 1 | 3% | — flat |
| Seat Belts | 1 | 3% | — flat |
2 NHTSA recall campaigns on file. Recall repairs are free at franchised dealers.
Defect
IF ONE OF THE HEADLAMP WIPER ARMS BECOMES MISALIGNED, THE WIPER BALDE CAN LODGE IN THE GROOVE UNDER THE HEADLAMP. IF THE WASHERS ARE ACTIVATED WITH THE WIPER BLADE IN THE MISALIGNED AND LODGED POSITION, THE WASHER PUMP WILL RUN CONTINUOUSLY EXPELLING ALL AVAILABLE FLUID.
Consequence
PUMP OPERATION IN THE ABSENCE OF FLUID CAN CAUSE THE PUMP TO OVERHEAT AND CAUSE A VEHICLE FIRE.
Remedy
DEALERS WILL REPLACE THE HEADLAMP WASHER PUMP ON THESE VEHICLES.
Defect
DUE TO HEAT EFFECTS, THE THROTTLE BUSHING LOCATED ON THE ACCELERATOR CONTROL CABLE, CAN FATIGUE AND BREAK, CAUSING THE THROTTLE LINKAGE TO SEPARATE.
Consequence
IF THE THROTTLE LINKAGE SEPARATES, THE ENGINE WILL RETURNTO IDLE SPEED, AND REMAIN AT IDLE, WITH NO ACCELERATION ABILITY. LOSS OF ENGINESPEED WITHOUT PRIOR WARNING COULD LEAD TO LOSS OF VEHICLE CONTROL AND ANACCIDENT.
Remedy
REPLACE THE THROTTLE BUSHING WITH A NEW BUSHING MADE FROM MORE HEAT-RESISTANT MATERIALS.
Representative excerpts, cleaned of personal information. These are consumer statements, not verified defects.
“WHEN THE VEHICLE IS PROCEEDING FORWARD FROM A FULL STOP AND IS TURNING TO EITHER THE RIGHT OR LEFT THERE IS A SERIOUS VIBRATION AND SHUTTERING PROBLEM. THE VEHICLE HAS HAD MANY FRONT-END ALIGNMENTS AND HAS HAD THE TRANSFER CASE REPLACED TWICE, THE PROBLEM STILL PERSISTS. *CJ”
“ENGINE DIES WHILE DRIVING AFTER ABOUT THE FIRST 5 MINUTES WHEN THE ENGINE DIES IT CANNOT BE RESTARTED WITHOUT TURNING THE KEY OFF WHICH LOCKS THE STEERING WHILE YOUR STILL MOVING. THE CAR IS UNSAFE TO DRIVE BECAUSE YOU CAN BE HIT FROM BEHIND BY ANOTHER CAR. THE REPAIR SHOP HAS FOUND THE PROBLEM TO…”
“DURING A FRONTAL IMPACT ACCIDENT AT 35 MPH. THE DRIVER'S SIDE AIR BAG DID NOT DEPLOY. PASSENGER'S SIDE SHOULDER BELT DID NOT RETRACT, RESULTING IN AN INJURY. *AK”
“MY 1991 300SL BENZ HAS HAD TO HAVE THE ENGINE WIRING HARNESS REPLACED PER MB DEALER BECAUSE IT'S GOING BAD AND DECOMPOSING CAUSING A POTENTIAL FIRE PROBLEM. THIS AFTER A NO START PROBLEM AND A MONTH IN THE SHOP. AND THEY NOT BEING ABLE TO FIND THE CAUSE. NOW , AFTER REPLACING THE HARNESS , THEY ARE…”
“WHILE DRIVING ABOUT 50 MPH ACCELERATOR GOT STUCK, CAUSING VEHICLE TO GO UP TO 80 TO 100 MPH. CONSUMER HAD TO PUT VEHICLE INTO ANOTHER GEAR TO GET VEHICLE TO STOP ALSO, BRAKE SYSTEM CAUGHT ON FIRE. *AK”
NHTSA data argues against it: 32 complaints put the 1991 model at #3 of 23 300 years. It is one of the 300 years to avoid.
According to NHTSA complaint data, the leading problem areas are transmission (7 complaints), engine (5 complaints), airbags (4 complaints).
Yes — NHTSA lists 2 recall campaigns affecting the 1991 Mercedes-Benz 300. Recall repairs are free at franchised dealers; check the VIN at nhtsa.gov/recalls to confirm the work was done.
Based on complaint rates and open investigations, the 300 years to avoid are 1993, 1987, 1991. The cleanest record among 300 years belongs to 1972.
Based on NHTSA ODI data through June 2026. Complaints are consumer-reported and unverified. Updated July 5, 2026.
Compiled by Sharon Ben-Moshe, Founder.