2018 Mercedes-Benz E-Class Reliability Report

Crankcase ventilation valve failures come up repeatedly. Symptoms are a check engine light with code P052E, oil leaks, and stalling on the road. Oil can seep into the engine harness, which raises the repair bill well past the valve itself, and one valve failed again after it had been replaced. Two fires are reported. One started in the engine bay while the car sat parked with the engine off. Another report describes a burning smell from the engine. Piston failure on the M247 engine is also reported, just after the warranty ran out.

The transmission drops into neutral and refuses to go into drive, sometimes in traffic, and one car was towed in with transmission failure. Shifts between drive and reverse fail now and then, so the car can move the wrong way if the driver does not notice. Fixes reported include a shifter module, a clutch position switch module, and an electronic valve body after the car went into limp mode at 83,000 miles. One complaint here is about the crankcase ventilation (PCV) valve and its high labor cost.

Front seat belts fail to retract after they are unbuckled. Slack is left across the driver's chest and lap. In one case a dealer diagnosed a failed belt motor, which is part of the PRE-SAFE system. A separate complaint describes a passenger belt that will not latch into its buckle, and mechanics could not find the cause. Both problems leave occupants without a properly fitted belt.

Alloy wheels on the AMG E43 crack along the inner lip during normal driving, which causes slow air leaks. Cracks are reported starting around 9,000 miles. One owner went through three front wheels and four front tires by 22,000 miles, and one crack ran several inches, close to a structural failure. A dealer welded a cracked wheel instead of replacing it. Front tires on these cars wore out in under 16,000 miles.

On level ground, the front doors swing shut on people getting out, and owners report bruised legs. The hinges were replaced once under warranty, and the dealer later said they were operating as designed. A rear roof spoiler came loose, banged against the rear window, and flew off at 60 mph, hitting another car. It had already been reattached after earlier repairs. On the Cabriolet, cords holding the headliner to the roof fray, so the top cannot open or close, and the dealer fix has not lasted.

Automatic emergency braking engages with nothing in the road. One car braked hard on a city street. Another came to a full stop on an open county road at 35 to 40 mph. No other vehicles were close, so no one was hit from behind, but the risk of a rear-end crash is clear. A mechanic found no fault codes in one car and updated its software.

Two crashes ended with no deployment at all. In one, the car struck the side of another vehicle at 30 mph, the driver's face and chest hit the steering wheel, and two vertebrae were damaged. In the other, the car pushed forward while parking and went through a storefront, with a lane change warning showing at the time. Both cars were totaled. In the storefront crash, the dealer has not reproduced the problem and the manufacturer has not confirmed it.