Owners have filed 36 complaints
about the 2005 Mercedes Benz SLK350 with NHTSA between 2007 and 2025.
The largest single group is the transmission & drivetrain.
Across this model's run it ranks 1 of 3 worst.
The letter says how bad. This says what kind — whether this year drew
an unusual number of complaints, unusually dangerous
ones, or failures that arrived unusually early.
The dashed ring is 50 — the national norm. Further out is worse.
Complaint volume — 87
Against the median year of the Mercedes Benz SLK350. 50 means typical for this
model; 100 means roughly double.
Severity — 100
36.1% of these complaints
involved a crash, fire, injury or death, against a national rate of
9.7%.
Early failure — 50
29% of failures with a mileage on record happened under
36,000 miles, against a national rate of
29%.
How 2005 compares with every other Mercedes Benz SLK350
Complaints filed with NHTSA, by model year. Bar colour is the FaultScore grade:
A
B
C
D
F
ungraded
What breaks on a 2005 Mercedes Benz SLK350
Every complaint is filed against a part. Follow any row for the complaints about that part alone.
Other & Unspecified
616.7%
1 crashes, 1 fires · median 160,000 mi
Transmission & Drivetrain
616.7%
Median failure at 45,000 miles
Suspension
513.9%
1 crashes, 0 fires
Brakes
513.9%
1 crashes, 1 fires · median 160,000 mi
Engine & Cooling
411.1%
1 crashes, 0 fires · median 56,851 mi
Fuel & Propulsion
38.3%
1 crashes, 0 fires · median 56,851 mi
Electrical System
25.6%
0 crashes, 1 fires · median 97,500 mi
Windows, Mirrors & Wipers
12.8%
Lights
12.8%
Acceleration & Cruise Control
12.8%
Median failure at 45,000 miles
Body & Structure
12.8%
Steering
12.8%
Median failure at 35,000 miles
When it fails
Odometer readings owners gave when they filed. About half of all
complaints include one.
10,000 – 24,999 miles
15.9%
25,000 – 49,999 miles
635.3%
50,000 – 74,999 miles
529.4%
75,000 – 99,999 miles
15.9%
150,000+ miles
423.5%
When owners complained
A spike years after the car went on sale usually means a part wearing
out on schedule across the whole fleet — the kind of pattern no single
owner can see from inside their own car.
Apr 2007peak 5Aug 2025
Complaints that involved harm
Reports where the owner recorded a crash, a fire, an injury or a death.
Celebration, FLCrash3 injured
UNKNOWN OR OTHER
The brake lines are rusted from the rear sub Frame that was rusted And caused an accident. They told me the sub frame was the only item covered but that they could only bolt it and not weld if and then the exhaust and brake lines (rusted too bad to describe) weren’t covered and since I couldn’t afford it they only repaired the subframe and left the rest hanging ! My brakes failed on the way home. No one was injured but I can’t believe they let me go home with that condition!
NHTSA complaint #11608172 — an unverified report by a vehicle owner.
Celebration, FLCrash3 injured
SUSPENSION
The brake lines are rusted from the rear sub Frame that was rusted And caused an accident. They told me the sub frame was the only item covered but that they could only bolt it and not weld if and then the exhaust and brake lines (rusted too bad to describe) weren’t covered and since I couldn’t afford it they only repaired the subframe and left the rest hanging ! My brakes failed on the way home. No one was injured but I can’t believe they let me go home with that condition!
NHTSA complaint #11608172 — an unverified report by a vehicle owner.
Celebration, FLCrash3 injured
SERVICE BRAKES
The brake lines are rusted from the rear sub Frame that was rusted And caused an accident. They told me the sub frame was the only item covered but that they could only bolt it and not weld if and then the exhaust and brake lines (rusted too bad to describe) weren’t covered and since I couldn’t afford it they only repaired the subframe and left the rest hanging ! My brakes failed on the way home. No one was injured but I can’t believe they let me go home with that condition!
NHTSA complaint #11608172 — an unverified report by a vehicle owner.
Celebration, FL1 injured
UNKNOWN OR OTHER
As i was driving (on a bridge) the convertible top/roof gushed and dumped an incredible amount of hydraulic fluid/oil right in my face unexpectedly! This came out of the blue. I had just raised it since it began to rain. The combination of raining weather and being on a one lane bridge and then having that spew into my face rendered me unable to see and had Me swerving almost off the bridge as the other lane had vehicles driving. I almost wrecked and was left with highly painful eyes. In truth it could have lead to death without question had I not had a towel in my passenger seat to wipe my face. I’m now terrified to drive it but have to. Please help, especially if any others are having the same issue, which seems to be the case. I could have had an accident or worse had an accident with others and off of the bridge!
NHTSA complaint #11546292 — an unverified report by a vehicle owner.
Celebration, FL1 injured
VISIBILITY/WIPER
As i was driving (on a bridge) the convertible top/roof gushed and dumped an incredible amount of hydraulic fluid/oil right in my face unexpectedly! This came out of the blue. I had just raised it since it began to rain. The combination of raining weather and being on a one lane bridge and then having that spew into my face rendered me unable to see and had Me swerving almost off the bridge as the other lane had vehicles driving. I almost wrecked and was left with highly painful eyes. In truth it could have lead to death without question had I not had a towel in my passenger seat to wipe my face. I’m now terrified to drive it but have to. Please help, especially if any others are having the same issue, which seems to be the case. I could have had an accident or worse had an accident with others and off of the bridge!
NHTSA complaint #11546292 — an unverified report by a vehicle owner.
at 160,000 milesSanta Barbara, CAFire
UNKNOWN OR OTHER
THE EMERGENCY BRAKE LINE CAUGHT FIRE UNDERNEATH THE ARM REST COMPARTMENT. TRACED THE LINE BACK TO REAR TIRES AND NOTHING ELECTRICAL COULD BE SEEN TOUCHING BRAKE CABLE LINE. SO NO OBVIOUS REASON WHY CABLE WOULD IGNITE. I WAS PARKED IN CAR PORT STALL AFTER A SHORT TRIP TO A FRIENDS HOUSE.
NHTSA complaint #11047045 — an unverified report by a vehicle owner.
The most recent complaints
In the owners' own words, exactly as filed with NHTSA.
at 171,000 milesKissimmee, FL
SERVICE BRAKES
The contact owns a 2005 Mercedes-Benz SLK-350. The contact stated that while driving at an undisclosed speed, the brake pedal was depressed; however, the vehicle failed to stop as intended. The contact stated that the vehicle eventually came to a rolling stop on the side of the road. In addition, the parking brake was activated; however, but failed to activate as intended. The contact stated that the low brake fluid warning light was illuminated. The contact refilled the brake fluid reservoir. The contact stated that the vehicle was almost involved in two crashes because of the failure. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The dealer was made aware of the failure; however, the contact was informed that the repair was not covered under warranty. In addition, the contact stated that the vehicle was serviced a year prior for an extended warranty repair to prevent suspension corrosion. The contact stated that the dealer advised the contact not to drive the vehicle due to evidence of brake line corrosion. The manufacturer was made aware of the failure but provided no assistance. The failure mileage was approximately 171,000.
NHTSA complaint #11683949 — an unverified report by a vehicle owner.
Celebration, FLCrash3 injured
UNKNOWN OR OTHER
The brake lines are rusted from the rear sub Frame that was rusted And caused an accident. They told me the sub frame was the only item covered but that they could only bolt it and not weld if and then the exhaust and brake lines (rusted too bad to describe) weren’t covered and since I couldn’t afford it they only repaired the subframe and left the rest hanging ! My brakes failed on the way home. No one was injured but I can’t believe they let me go home with that condition!
NHTSA complaint #11608172 — an unverified report by a vehicle owner.
Celebration, FLCrash3 injured
SUSPENSION
The brake lines are rusted from the rear sub Frame that was rusted And caused an accident. They told me the sub frame was the only item covered but that they could only bolt it and not weld if and then the exhaust and brake lines (rusted too bad to describe) weren’t covered and since I couldn’t afford it they only repaired the subframe and left the rest hanging ! My brakes failed on the way home. No one was injured but I can’t believe they let me go home with that condition!
NHTSA complaint #11608172 — an unverified report by a vehicle owner.
Celebration, FLCrash3 injured
SERVICE BRAKES
The brake lines are rusted from the rear sub Frame that was rusted And caused an accident. They told me the sub frame was the only item covered but that they could only bolt it and not weld if and then the exhaust and brake lines (rusted too bad to describe) weren’t covered and since I couldn’t afford it they only repaired the subframe and left the rest hanging ! My brakes failed on the way home. No one was injured but I can’t believe they let me go home with that condition!
NHTSA complaint #11608172 — an unverified report by a vehicle owner.
Phila, PA
POWER TRAIN
the conductor plate along with its speed sensor is faulty. Luckily I just exit the highway, the transmission just stopped working, can't drive forward or reverse and when I apply gas on either D or R, just the RPM speed up as if the car is in neutral. I was stranded on the middle of the road. this happened a few time. after turning off the car and turn it back on usually reset it for a little bit. the first time, I have to replace the transmission.
NHTSA complaint #11592159 — an unverified report by a vehicle owner.
Dayton, OH
POWER TRAIN
transmission lines popping off popped off at 60 miles per hour tensed me up it stared smoking pushed the safety hazzard lights on and was able to limp it off the highway its happened 3 times after i repaired them afraid to even drive it now.no no no
NHTSA complaint #11548815 — an unverified report by a vehicle owner.
Dayton, OH
UNKNOWN OR OTHER
transmission lines popping off popped off at 60 miles per hour tensed me up it stared smoking pushed the safety hazzard lights on and was able to limp it off the highway its happened 3 times after i repaired them afraid to even drive it now.no no no
NHTSA complaint #11548815 — an unverified report by a vehicle owner.
Celebration, FL1 injured
UNKNOWN OR OTHER
As i was driving (on a bridge) the convertible top/roof gushed and dumped an incredible amount of hydraulic fluid/oil right in my face unexpectedly! This came out of the blue. I had just raised it since it began to rain. The combination of raining weather and being on a one lane bridge and then having that spew into my face rendered me unable to see and had Me swerving almost off the bridge as the other lane had vehicles driving. I almost wrecked and was left with highly painful eyes. In truth it could have lead to death without question had I not had a towel in my passenger seat to wipe my face. I’m now terrified to drive it but have to. Please help, especially if any others are having the same issue, which seems to be the case. I could have had an accident or worse had an accident with others and off of the bridge!
NHTSA complaint #11546292 — an unverified report by a vehicle owner.
Celebration, FL1 injured
VISIBILITY/WIPER
As i was driving (on a bridge) the convertible top/roof gushed and dumped an incredible amount of hydraulic fluid/oil right in my face unexpectedly! This came out of the blue. I had just raised it since it began to rain. The combination of raining weather and being on a one lane bridge and then having that spew into my face rendered me unable to see and had Me swerving almost off the bridge as the other lane had vehicles driving. I almost wrecked and was left with highly painful eyes. In truth it could have lead to death without question had I not had a towel in my passenger seat to wipe my face. I’m now terrified to drive it but have to. Please help, especially if any others are having the same issue, which seems to be the case. I could have had an accident or worse had an accident with others and off of the bridge!
NHTSA complaint #11546292 — an unverified report by a vehicle owner.
Celebration, FL
UNKNOWN OR OTHER
My vehicle has excessive rust issues that I’m being told by the dealership will compromise my safety. There is currently an extension of warranty for only the subframe in rear, but the rust is extended beyond that and is applied to the components needed to be removed in order to replace the subframe. Such as the exhaust pipe and brake lines as well. All are corroded to a high degree up to and including complete brittle material Disintegration. Exhaust and rear brake line cost make it impossible for me to have the vehicle brought back to safely drivable conditions. I have to get to work daily or my family will not eat or have a roof but at a cost of more than what the car is even worth I have no choice but to choose and compromise my safety and those around me or food and shelter for my family. Please help.
NHTSA complaint #11544770 — an unverified report by a vehicle owner.
Celebration, FL
SUSPENSION
My vehicle has excessive rust issues that I’m being told by the dealership will compromise my safety. There is currently an extension of warranty for only the subframe in rear, but the rust is extended beyond that and is applied to the components needed to be removed in order to replace the subframe. Such as the exhaust pipe and brake lines as well. All are corroded to a high degree up to and including complete brittle material Disintegration. Exhaust and rear brake line cost make it impossible for me to have the vehicle brought back to safely drivable conditions. I have to get to work daily or my family will not eat or have a roof but at a cost of more than what the car is even worth I have no choice but to choose and compromise my safety and those around me or food and shelter for my family. Please help.
NHTSA complaint #11544770 — an unverified report by a vehicle owner.
Celebration, FL
SERVICE BRAKES
My vehicle has excessive rust issues that I’m being told by the dealership will compromise my safety. There is currently an extension of warranty for only the subframe in rear, but the rust is extended beyond that and is applied to the components needed to be removed in order to replace the subframe. Such as the exhaust pipe and brake lines as well. All are corroded to a high degree up to and including complete brittle material Disintegration. Exhaust and rear brake line cost make it impossible for me to have the vehicle brought back to safely drivable conditions. I have to get to work daily or my family will not eat or have a roof but at a cost of more than what the car is even worth I have no choice but to choose and compromise my safety and those around me or food and shelter for my family. Please help.
NHTSA complaint #11544770 — an unverified report by a vehicle owner.
Phila, PA
ENGINE
improper heat treatment of the balance shaft spocket causing the balance shaft to worn out resulting in advance timing of the CAM. Mercedes acknowledges it's an known issue but don't cover cost of fixing it. Once ecu detected timing is off, it will stop the transmission from accelerating without any warning. Happened to me on a highway, good thing the car still have some momentum and was able to pull to the shoulder while others cars are coming from behind.
NHTSA complaint #11537700 — an unverified report by a vehicle owner.
Celebration, FL
SUSPENSION
The rear subframe is corroded to the point of about to fall off and subsequently anything that is attached. Mercedes has extended a warranty on the subframe which is excellent, but only the subFrame? What about the touching bits like the bolts and screws among other items that are connected to it. So now because I cannot afford the $5,000.00 needed for the other rusted pieces that are brittle and likely to fall off when the subframe is replaced, then they won’t do it. So I must jeapordize my safety as I have to get to school and work.
NHTSA complaint #11533695 — an unverified report by a vehicle owner.
Raleigh, NC
SUSPENSION
A few days after a scheduled service visit at a local Mercedes-Benz (MB) dealer I noticed a creaking sound coming from the rear of my 2005 SLK350 that continued to get louder as time went by. I scheduled another appointment for post-inspection and I received the unfortunate news that corrosion of the subframe had resulted in a critical fracture rendering the vehicle unsafe to drive and that I was actually lucky to have not been involved in an accident from the mechanical failure. It is clear from the undercarriage photos that corrosion was localized to subframe junctions where other areas/parts in the vicinity did not experience debilitating fracture damage. I was surprised that a recently-serviced vehicle was now deemed unsafe to drive and required an entire rear subframe replacement. After some further investigation online (via forums, etc.) this appears to be a prominent issue with the R171 generation of rear subframes where corrosion protection was not applied to the steel subframe interior during manufacturing, which results in corrosion from the inside out, and thus by the time the problem is visually evident it is much too late from a life safety standpoint.
NHTSA complaint #11469622 — an unverified report by a vehicle owner.
Raleigh, NC
STRUCTURE:BODY
A few days after a scheduled service visit at a local Mercedes-Benz (MB) dealer I noticed a creaking sound coming from the rear of my 2005 SLK350 that continued to get louder as time went by. I scheduled another appointment for post-inspection and I received the unfortunate news that corrosion of the subframe had resulted in a critical fracture rendering the vehicle unsafe to drive and that I was actually lucky to have not been involved in an accident from the mechanical failure. It is clear from the undercarriage photos that corrosion was localized to subframe junctions where other areas/parts in the vicinity did not experience debilitating fracture damage. I was surprised that a recently-serviced vehicle was now deemed unsafe to drive and required an entire rear subframe replacement. After some further investigation online (via forums, etc.) this appears to be a prominent issue with the R171 generation of rear subframes where corrosion protection was not applied to the steel subframe interior during manufacturing, which results in corrosion from the inside out, and thus by the time the problem is visually evident it is much too late from a life safety standpoint.
NHTSA complaint #11469622 — an unverified report by a vehicle owner.
at 76,000 milesBala Cynwyd, PA
FUEL/PROPULSION SYSTEM
THE FUEL GAUGE IS WORKING ERRATICALLY. AFTER FILLING UP WITH FUEL, GAUGE SHOWS 3/4 FULL. NEXT MORNING, SHOWS FULL. AFTER DRIVING 25 MILES INTO WORK, FUEL GAUGE SHOW 1/4 FULL. END OF THE DAY, FUEL GAUGE SHOWS 1/2 FULL OR EMPTY. THE READING CAN BE ALMOST ANYWHERE AND IS UNRELIABLE. I HAVE HAD TO RESORT TO TRACKING MILEAGE AND FILLING UP BEFORE RUNNING OUT OF FUEL. THE CAR HAS RUN OUT OF FUEL ON A FEW OCCASIONS CAUSING THE CAR TO LOSE POWER AND SPEED ON A MAJOR HIGHWAY WHICH IS VERY UNSAFE.
NHTSA complaint #11328196 — an unverified report by a vehicle owner.
Cherry Hill, NJ
UNKNOWN OR OTHER
REAR SUBFRAME RUSTING FROM THE INSIDE OUT. DUE TO POOR DESIGN, THERE IS AN ARCH THAT HOLDS WATER IN AND THE WATER CAN'T GET OUT CAUSING IT RUST FROM THE INSIDE OUT. SEARCHING MERCEDES ONLINE FORUMS, THIS SEEMS LIKE A PROBLEM LOTS OF PEOPLE PROBLEM AND MERCEDES DENIES THIS PROBLEM. I HAVEN'T HAD AN ACCIDENT YET, BUT IT SEEMS LIKE IT IF I DON'T REPLACE IT. HTTPS://WWW.SLKWORLD.COM/SEARCH/55011/?Q=SUBFRAME&O=RELEVANCE HTTPS://WWW.GOOGLE.COM/SEARCH?Q=MERCEDES+SUBFRAME+RUST&OQ=MERCEDES+SUBFRAME+RU&AQS=CHROME.1.69I57J0L3.10211J0J7&CLIENT=MS-ANDROID-HUAWEI-REV1&SOURCEID=CHROME-MOBILE&IE=UTF-8 THE FOLLOWING PERSONS CAR WAS FLIPPED WHILE IN THE HIGH WAY. HTTPS://WWW.SLKWORLD.COM/THREADS/REAR-SUBFRAME-R171.553156
NHTSA complaint #11307869 — an unverified report by a vehicle owner.
Cherry Hill, NJ
SUSPENSION
REAR SUBFRAME RUSTING FROM THE INSIDE OUT. DUE TO POOR DESIGN, THERE IS AN ARCH THAT HOLDS WATER IN AND THE WATER CAN'T GET OUT CAUSING IT RUST FROM THE INSIDE OUT. SEARCHING MERCEDES ONLINE FORUMS, THIS SEEMS LIKE A PROBLEM LOTS OF PEOPLE PROBLEM AND MERCEDES DENIES THIS PROBLEM. I HAVEN'T HAD AN ACCIDENT YET, BUT IT SEEMS LIKE IT IF I DON'T REPLACE IT. HTTPS://WWW.SLKWORLD.COM/SEARCH/55011/?Q=SUBFRAME&O=RELEVANCE HTTPS://WWW.GOOGLE.COM/SEARCH?Q=MERCEDES+SUBFRAME+RUST&OQ=MERCEDES+SUBFRAME+RU&AQS=CHROME.1.69I57J0L3.10211J0J7&CLIENT=MS-ANDROID-HUAWEI-REV1&SOURCEID=CHROME-MOBILE&IE=UTF-8 THE FOLLOWING PERSONS CAR WAS FLIPPED WHILE IN THE HIGH WAY. HTTPS://WWW.SLKWORLD.COM/THREADS/REAR-SUBFRAME-R171.553156
NHTSA complaint #11307869 — an unverified report by a vehicle owner.
Mechanicsburg, PA
EXTERIOR LIGHTING
SIDE MARKER BULBS CONSTANTLY BURNING OUT. PURCHASED CAR IN 2012, AND EVERY ANNUAL INSPECTION NEED TO REPLACE BULBS. BUT AFTER ABOUT TWO WEEKS, THEY BURN OUT AGAIN. WAS TOLD BY MECHANIC WIRING IN LIGHT ASSEMBLY DEFECTIVE. COST TO REPLACE ASSEMBLY ESTIMATED $150 PER SIDE/$300 FOR BOTH - EXCLUDING LABOR. IF ASSEMBLY DEFECTIVE, FEEL I SHOULD NOT ABSORB COST TO REPLACE. AN OBVIOUS MERCEDES DEFECT.
NHTSA complaint #11103092 — an unverified report by a vehicle owner.
at 160,000 milesSanta Barbara, CAFire
UNKNOWN OR OTHER
THE EMERGENCY BRAKE LINE CAUGHT FIRE UNDERNEATH THE ARM REST COMPARTMENT. TRACED THE LINE BACK TO REAR TIRES AND NOTHING ELECTRICAL COULD BE SEEN TOUCHING BRAKE CABLE LINE. SO NO OBVIOUS REASON WHY CABLE WOULD IGNITE. I WAS PARKED IN CAR PORT STALL AFTER A SHORT TRIP TO A FRIENDS HOUSE.
NHTSA complaint #11047045 — an unverified report by a vehicle owner.
at 160,000 milesSanta Barbara, CAFire
ELECTRICAL SYSTEM
THE EMERGENCY BRAKE LINE CAUGHT FIRE UNDERNEATH THE ARM REST COMPARTMENT. TRACED THE LINE BACK TO REAR TIRES AND NOTHING ELECTRICAL COULD BE SEEN TOUCHING BRAKE CABLE LINE. SO NO OBVIOUS REASON WHY CABLE WOULD IGNITE. I WAS PARKED IN CAR PORT STALL AFTER A SHORT TRIP TO A FRIENDS HOUSE.
NHTSA complaint #11047045 — an unverified report by a vehicle owner.
at 160,000 milesSanta Barbara, CAFire
SERVICE BRAKES
THE EMERGENCY BRAKE LINE CAUGHT FIRE UNDERNEATH THE ARM REST COMPARTMENT. TRACED THE LINE BACK TO REAR TIRES AND NOTHING ELECTRICAL COULD BE SEEN TOUCHING BRAKE CABLE LINE. SO NO OBVIOUS REASON WHY CABLE WOULD IGNITE. I WAS PARKED IN CAR PORT STALL AFTER A SHORT TRIP TO A FRIENDS HOUSE.
NHTSA complaint #11047045 — an unverified report by a vehicle owner.
at 30,000 milesTruro, MA
FUEL/PROPULSION SYSTEM
TL* THE CONTACT OWNS A 2005 MERCEDES BENZ SLK350. THE CONTACT STATED THAT THERE WAS A STRONG ODOR OF FUEL INSIDE THE VEHICLE. THE VEHICLE WAS TAKEN TO A DEALER, BUT WAS NOT DIAGNOSED OR REPAIRED. THE MANUFACTURER WAS MADE AWARE OF THE FAILURE. THE FAILURE MILEAGE WAS 30,000.
NHTSA complaint #10743294 — an unverified report by a vehicle owner.
at 67,501 milesPhila, PA
POWER TRAIN
JUST GOT OFF THE HIGH WAY AND DRIVE ONTO A LOCAL STREET, THE CAR WOULD NOT SHIFT INTO ANY GEAR FORWARD OR REVERSE. END UP HAVING TO TOW THE CAR. LUCKILY IT DIDN'T HAPPEN WHILE I WAS AT THE HIGHWAY.
NHTSA complaint #10667301 — an unverified report by a vehicle owner.