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2018 Mercedes Benz C Class Recalls, Issues & Maintenance

The 2018 Mercedes Benz C Class has no open NHTSA recalls. Owners report 7 recurring issue clusters, led by “Positive crankcase ventilation valve failure.” Mercedes-Benz alternates two service events: Service A (oil, filter, inspection) at roughly 10,000 miles or 1 year, then Service B (Service A plus brake fluid, cabin filter, and deeper checks) at roughly 20,000 miles or 2 years — the ASSYST Plus counter in the cluster tells you which is due. Oil must carry the MB-Approval number your engine specifies (commonly 229.5, or 229.71 for newer 0W-20 engines); 'meets or exceeds' marketing language is not an approval. Electric EQB and EQS models keep the A/B rhythm for inspections, brake fluid, and cabin filters — just without oil.

No open recalls on file. NHTSA lists no unrepaired safety recalls for this year, make and model. A recall can be issued at any time, and a specific car can still have one open — check yours by VIN at nhtsa.gov/recalls.

Known issues for this vehicle

What drivers and federal regulators have officially reported about the 2018 Mercedes Benz C Class.

Reported to NHTSA

Positive crankcase ventilation valve failure

ENGINE

35 NHTSA complaints · 2022-02 → 2026-01

“The engine light is on with only 35000 miles. Upon using an OBD2 scanner, error code P052e positive crankcase ventilation(PCV) malfunction was detected. It's a problem that I researched and noticed a lot of people having the same issue”
— Owner report, NHTSA ODI #11640265
“Has 27000 miles out of warranty at 5 years. PCV code bad actuator. Looks like a common problem. Should be recalled”
— Owner report, NHTSA ODI #11525844
“Error code P052E Positive crankcase ventilation regulator valve performance”
— Owner report, NHTSA ODI #11577820

Read all complaints on NHTSA →

Front roof panel or sunroof detachment

STRUCTURE

13 NHTSA complaints · 2020-07 → 2026-07

“The contact owns a 2018 Mercedes-Benz C300. The contact stated that while driving approximately 60 MPH, a part of the panoramic roof towards the driver's side detached from the vehicle. The contact pulled over to inspect the vehicle”
— Owner report, NHTSA ODI #11681537
“The contact owns a 2018 Mercedes-Benz C300. The contact stated while driving at approximately 65 MPH, there was a windy sound coming from the front of the vehicle. The contact then noticed the sound of an impact on the rear driver's side of the vehicle”
— Owner report, NHTSA ODI #11586820
“THE SUNROOF SPONTANEOUSLY EXPLODED OUT OF NO WHERE. SOUNDED LIKE A SHOTGUN BLAST”
— Owner report, NHTSA ODI #11341232

Read all complaints on NHTSA →

Rear window bonding separation from convertible top

VISIBILITY

4 NHTSA complaints · 2023-08 → 2025-06

“The contact owns a 2018 Mercedes-Benz C300. The contact stated that while driving at an undisclosed speed, the rear window glass which was not properly bonded had become loosened”
— Owner report, NHTSA ODI #11617349
“The contact owns a 2018 Mercedes-Benz C300. The contact stated that after washing the vehicle, the contact became aware that the adhesive attaching the rear window to the convertible top had started to detach”
— Owner report, NHTSA ODI #11664906
“Incorrect bonding of the rear window. The rear window bond is failing which is causing the window to detach from the convertible top”
— Owner report, NHTSA ODI #11538137

Read all complaints on NHTSA →

SOS emergency call system recall repair delay

ELECTRICAL SYSTEM, COMMUNICATION

6 NHTSA complaints · 2021-04 → 2023-03

“The contact owns a 2018 Mercedes-Benz C300. The contact stated that after starting the vehicle, the S.O.S. Not Active message displayed. The contact was concerned that in the event of an emergency, the emergency services function would be inoperable”
— Owner report, NHTSA ODI #11511208
“The contact owns a 2018 Mercedes-Benz C300. The contact stated that the SOS warning light was illuminated. Upon testing the SOS system, the contact stated that the system failed to operate as needed”
— Owner report, NHTSA ODI #11475159
“The contact owns a 2018 Mercedes-Benz C300 4matic. The contact received notification of NHTSA Campaign Number: 21V058000 (Communication, Electrical System) however, the part to do the recall repair was not yet available”
— Owner report, NHTSA ODI #11418776

Read all complaints on NHTSA →

Tire blowouts and premature tread wear

TIRES

8 NHTSA complaints · 2019-01 → 2025-05

“I HAVE OWNED THE CAR FOR ABOUT 14 MONTHS AND DRIVEN JUST OVER 10,000 MILES DURING THAT TIME. I HAVE NOW HAD MY FIFTH FLAT OR DAMAGED FRONT TIRE SINCE OWNERSHIP OCCURRING ON BOTH DRIVER SIDE AND PASSENGER SIDE”
— Owner report, NHTSA ODI #11171194
“TL* THE CONTACT OWNS A 2018 MERCEDES-BENZ C63S EQUIPPED WITH MICHELIN PILOT SPORT TIRES, SIZE: 285/30/ZR19 (NA). THE CONTACT STATED THAT THE FRONT PASSENGER TIRE BLEW OUT WHILE DRIVING 60 MPH”
— Owner report, NHTSA ODI #11268993
“2 BLOWOUTS, 1 TIRE SHREDDED, 1 VALVE STEM LEAK. BLOW OUT AT 11, 800 MILES”
— Owner report, NHTSA ODI #11196193

Read all complaints on NHTSA →

Cracked piston or crankshaft requiring engine replacement

ENGINE

7 NHTSA complaints · 2022-01 → 2025-10

“My vehicle only had 31,000 miles and I experienced engine failure. I bought a new engine for 16, 500. 00 dollars. Mercedes Benz did nothing”
— Owner report, NHTSA ODI #11695170
“CRACKED PISTON AT 68K MILES The vehicle is very well maintained, only 68k miles, has had every oil change, only takes premium gas. I was driving it when the check engine light went on and the vehicle began shaking violently”
— Owner report, NHTSA ODI #11478301
“Car needs an engine rebuild at 90K miles due to a cracked piston #1, a problem with a car that received regular oil change intervals and proper service should not have”
— Owner report, NHTSA ODI #11590907

Read all complaints on NHTSA →

Steering rack locknut recall parts unavailable

STEERING

10 NHTSA complaints · 2019-02 → 2021-07

“RECALL LETTER STATES DEFECTIVE NUT IN STEERING COLUMN REPLACEMENT PART IS NOT AVAILABLE AND NO DATE IS GIVEN WHEN IT WILL BE AVAILABLE. LETTER WARNS IF THE PART (NUT)) CRACKS THERE IS A RISK OF A CRASH”
— Owner report, NHTSA ODI #11180352
“I RECEIVED A LETTER FROM MERCEDES-BENZ USA, LLC IN JANUARY 2019 REGARDING A RECALL INVOLVING A LOCKNUT IN THE STEERING RACK WHICH MIGHT HAVE INTERNAL MATERIAL CRACKS AFFECTING MY MAKE/MODEL/YEAR OF CAR”
— Owner report, NHTSA ODI #11232247
“While driving in a curved onramp connecting from one street to another the vehicle experienced a complete loss of steering ability which resulted in the vehicle continuing to move straight, off the pavement, and into a wall”
— Owner report, NHTSA ODI #11423998

Read all complaints on NHTSA →

Issues on other model years

Source: NHTSA Office of Defects Investigation (ODI). Complaint data refreshed Sep 17, 2026. Investigation data refreshed Sep 17, 2026.

We display NHTSA's record with attribution; we don't editorialize on what these complaints mean for any specific vehicle.

Essential maintenance

Critical for safety and preventing major damage

Service A — Oil & Filter + Inspection

Every 10,000 mi

Every 10,000 miles or 12 months: oil and filter with MB-Approved oil, fluid top-offs, tire check, and inspection. AMG models driven hard: many owners service at 5,000-7,500 miles.

Estimated cost — typical U.S. ranges

Dealer

~$120–$160

Shop

~$85–$115

DIY

~$25–$55

Full synthetic costs more than conventional. 5-quart 0W-20 + filter is the typical bill.

Service B — Major Inspection

Every 20,000 mi

Every 20,000 miles or 2 years, alternating with Service A: everything in A plus brake-fluid replacement, cabin filter, and a deeper multi-point inspection of brakes, suspension, and driveline.

Estimated cost — typical U.S. ranges

Dealer

~$85

Shop

~$60

DIY

Free

Most shops do this free with any paid service. A flashlight and 10 minutes covers the basics yourself.

Tire Rotation

Every 10,000 mi

Rotate at every Service A where the tire sizes allow. Many AMG and 4MATIC+ models run staggered widths that can't rotate front-to-rear — check your spec before paying for a rotation.

Estimated cost — typical U.S. ranges

Dealer

~$85

Shop

~$60

DIY

Free

Often free at the shop where you bought the tires — worth asking before paying.

Brake Inspection

Every 10,000 mi

Checked at every A/B service via electronic pad-wear sensors. Replace sensors with pads. Heavy EQS models wear pads slowly (regen braking) but rotors can corrode from disuse — an inspection catches that.

Estimated cost — typical U.S. ranges

Dealer

~$85

Shop

~$60

DIY

Free

Most shops do this free as a courtesy with any service. Don't pay separately if you can avoid it.

Brake Fluid

Every 20,000 mi

Replaced every 2 years as part of Service B — Mercedes schedules it on time, not miles, because DOT 4 fluid absorbs moisture regardless of driving.

Estimated cost — typical U.S. ranges

Dealer

~$180–$200

Shop

~$125–$140

DIY

~$10–$25

DOT 3 or 4 — match the cap. Vacuum bleeders make this a one-person DIY.

Important maintenance

Keeps your vehicle running smoothly and efficiently

Automatic Transmission Fluid (7G / 9G-Tronic)

Every 70,000 mi

Mercedes specifies fluid and filter service around 70,000 miles on most 7G- and 9G-Tronic gearboxes — check your year's sheet. Use only the MB-spec fluid for your transmission code; independent specialists often service at 60,000 on hard-driven cars.

Estimated cost — typical U.S. ranges

Dealer

~$330–$500

Shop

~$235–$355

DIY

~$60–$180

Some sealed transmissions have no dipstick — fill is precise and best left to a shop. Many drivers can still DIY drain-and-fill.

Spark Plugs

Every 60,000 mi

Most modern MB gas engines: plugs around 60,000 miles — AMG engines often sooner. Check your engine's sheet; twin-turbo V8 plug jobs are labor-heavy, so pair with other scheduled work.

Estimated cost — typical U.S. ranges

Dealer

~$285–$390

Shop

~$200–$275

DIY

~$25–$100

Iridium plugs cost more but last 100k+ miles. V6/V8 access varies wildly — some are tough.

Engine Air Filter

Every 40,000 mi

Replace around every 40,000 miles (twin-filter setups on V6/V8 engines double the parts bill). Inspected at every Service B.

Estimated cost — typical U.S. ranges

Dealer

~$60–$95

Shop

~$45–$70

DIY

~$15–$40

5-minute job on most cars; the airbox lid usually has clips, no tools needed.

Recommended maintenance

Extends the life of your vehicle and improves comfort

Combination / Dust Filter

Every 20,000 mi

Replaced with every Service B. Models with the ENERGIZING air package use a higher-grade filter — priced accordingly.

Estimated cost — typical U.S. ranges

Dealer

~$60–$95

Shop

~$45–$70

DIY

~$15–$40

Usually behind the glovebox. Shops charge labor for a 10-minute job — easy DIY win.

Engine Coolant

On condition / lifetime

MB-spec coolant is long-life (typically ~10 years / 150,000 miles on the sheet). Refresh only with MB 325/326-spec coolant — the wrong chemistry attacks aluminum and head gaskets.

Estimated cost — typical U.S. ranges

Dealer

~$285–$330

Shop

~$200–$235

DIY

~$25–$60

Use the manufacturer-specified coolant — wrong color/chemistry can damage the cooling system.

12V & Auxiliary Battery

Every 25,000 mi

Test annually after year 3. Most modern Mercedes carry a second auxiliary battery; a weak one triggers cascading warning messages long before a no-start. EQ models also depend on the 12V system to boot.

Estimated cost — typical U.S. ranges

Dealer

~$225–$390

Shop

~$160–$280

DIY

~$130–$250

Most auto-parts stores test and install batteries free with purchase. Skip the dealer markup.

Fatal crash history & reported problems

Occupant deaths in fatal crashes (FARS)

19 crashes 2010–2024

FARS counts every occupant death in a fatal crash, whatever the cause — it does not mean the vehicle was at fault or defective. Counts are not adjusted for how many of each vehicle are on the road. How to read this number

Owner-reported problem signals

Separate from the federal fatality data above: complaints owners filed with NHTSA about this year and model. These are reports of problems, unverified, and are counted here only as signals.

5

complaints mentioning a crash

0

complaints mentioning a fire

Reviewed known issues for this vehicle

Typical U.S. ranges. Actual quotes vary by shop, parts choice, and vehicle condition.

How we estimate: Dealer = OEM parts × 1.4 + labor × $165/hr. Shop = parts + labor × $115/hr. DIY = parts only.

This maintenance schedule for the 2018 Mercedes Benz C Class reflects Mercedes-Benz's published service intervals and the ASSYST Plus (Service A / Service B) system. Your actual service needs may vary based on driving conditions, climate, and vehicle usage. Always consult your owner's manual for model-specific recommendations.

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