Tl* the contact owns a 2017 Mercedes benz c300. The contact stated that while driving 55 MPH and was going around a curve in the road, an abnormal sound was heard. The sun roof exploded without impact. The contact stated that the sun roof glass fell inside the cabin of the vehicle and on her son who was seated in his car seat in the rear of the vehicle. The contact and her son sustained minor…
2017 Mercedes-Benz C-Class visibility problems
severe 10 complaints filed with NHTSA · avg repair $350 · see visibility across all vehicles →
Complaints
10
Recalls
0
Avg fix
$350
2injuries
When does it fail?
Of the 10 visibility complaints filed for the 2017 Mercedes-Benz C-Class, here's the actual mileage breakdown — failures cluster heaviest at 0-25,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What stands out
Among the 9 model years of Mercedes-Benz C-Class in our records for visibility problems, this one ranks #3 by owner-complaint volume.
No new NHTSA visibility complaint has been filed on this vehicle in over 5 years — the issue may be aging out of the active population.
The failure pattern owners describe
Buyer takeaway: The 2017 Mercedes C-Class has reported serious visibility-component failures: windshield adhesive breakdown causing water leaks and compromised airbag support, plus multiple cases of sunroofs spontaneously exploding at highway speeds without warning or impact. Buyers should have any used C-Class of this generation thoroughly inspected for windshield bonding integrity and sunroof condition before purchase.
Owners report two major visibility-system failures. First, windshield adhesive fails to bond properly, causing the glass to come loose and allow water into the cabin. This typically shows up after a car wash when water starts dripping inside. The windshield becomes noticeably loose or "floppy" and structurally unreliable. Mercedes dealers have confirmed this defect and recommended full windshield replacement with new adhesive; one owner's insurance covered the repair through Safelite. Mercedes-Benz USA classified this as "wear and tear" and offered $400 toward repair.
Second, sunroofs spontaneously shatter or explode while driving—with no impact, no warning lights, and no apparent cause. Owners hear a loud pop or banging sound and then the glass either fractures badly or ejects completely, with shards falling inside the cabin or onto the roadway. This has happened at speeds ranging from 35 to 75 MPH and at mileages from 9,000 to 84,000 miles. One incident involved glass falling on a child in a car seat, causing minor injuries. A few owners also reported sunroofs that fail to close properly or open only partially. Dealers have not been able to determine the root cause of spontaneous sunroof failure.
Same Mercedes-Benz C-Class visibility reports on nearby years: 2015 · 2016
Failure modes owners describe
Windshield urethane adhesive failure
Windshield bonding adhesive fails to secure the windshield to the vehicle frame, allowing water intrusion into the cabin and compromising structural integrity. Owners report the windshield becoming loose or 'floppy' and losing proper attachment to the vehicle body.
When: Between 9,000 and 100,000 miles; typically discovered during or after car wash when water enters the cabin
Symptoms owners cite: Water leaking into cabin interior; Windshield loose or not properly attached; Windshield shifts or feels unstable; Glass appears to have poor bonding to frame
Repairs/costs cited: Dealership diagnosis: full windshield and adhesive replacement recommended. Insurance claims processed through Safelite. Manufacturer offered $400 toward repair, classifying as 'wear and tear.'
Recalls/TSBs owners mention: Mercedes-Benz USA case filed; manufacturer reviewed case and offered $400 toward repair, denying structural defect classification
Sunroof spontaneous explosion
Sunroof glass spontaneously fractures, shatters, or explodes while vehicle is in motion without any impact or warning. Glass falls into cabin or is ejected onto roadway. Occurs across a wide range of mileages and speeds.
When: Ranges from 9,000 to 84,000 miles; occurs while driving at speeds from 35 to 75 MPH
Symptoms owners cite: Loud popping or banging noise from roof before failure; Sunroof glass suddenly fractures or explodes; Glass falls into cabin or ejects onto roadway; No prior warning lights or alerts; Glass shards inside vehicle cabin
Repairs/costs cited: One owner reported minor scrapes requiring medical attention after glass fell on child in car seat. Dealers provided repair cost estimates but vehicles not repaired. Cause of failure not determined by dealers.
Recalls/TSBs owners mention: One manufacturer notification stated vehicle not covered under recall. One contact advised to file NHTSA complaint. One contact offered 'cost effective program' after notification.
Sunroof closure mechanism failure
Sunroof fails to close properly or opens only partially. One owner heard air entering sunroof and sunroof failed to close as designed. Another owner experienced one-sided opening where only the left side of sunroof opened.
When: 56,000 and 100,000 miles
Symptoms owners cite: Sunroof fails to close completely; Abnormal air noise from sunroof area; Sunroof opens only partially (one side only); No warning lights illuminated
Repairs/costs cited: Dealers contacted but diagnostic results and repairs uncertain; vehicles not confirmed repaired
Recalls/TSBs owners mention: Manufacturer notified in at least one case and offered 'cost effective program'; contact referred to NHTSA Hotline
Windshield cracking defect
Windshield develops long cracks on delivery from dealership or after service center repairs. One owner reports three windshield replacements due to cracking issues; cracks appeared on new replacements received from dealership and while vehicle was in Mercedes-Benz service center possession.
When: On delivery from dealership or during service center work
Symptoms owners cite: Long cracks on driver side of windshield; Long cracks across top of windshield; Defects present when picking up vehicle from dealership or service center
Repairs/costs cited: Three windshield replacements performed; second replacement cracked while vehicle was in Mercedes-Benz possession for 3 weeks to 1 month
Synthesized from 10 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 1 most recent
Had visibility trouble with your 2017 Mercedes-Benz C-Class?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the visibility problem on the 2017 Mercedes-Benz C-Class?
It's a meaningful issue. 10 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $350.
At what mileage does the visibility typically fail?
Based on the 10 complaints filed, visibility issues most often appear around 42,133 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
What does it cost to fix?
Independent shops typically charge around $350 for visibility repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to visibility?
No active recalls currently cover visibility issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2017/Mercedes-Benz/C-Class.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.