How reliable is the Mercedes E-Class Mk4?
Reliability surveys suggest the W212 family were more reliable than most of their competitors and certainly some of its direct ancestors of the 1990s and early 2000s, which were plagued with build-quality issues. Diesel injectors were known to fail on early models, but these should have long since been fixed by now. Pay particular attention to whether any parking sensors fitted to the car work properly if you're viewing a Mk4 E-Class.
Other known issues with this E-Class include:
- Intermittent failure of the keyless start system (usually fixed via software upgrade)
- Issues with the DAB radio sound (again, usually fixed via software)
- A noisy and quick-wearing alternator belt [1.6- and 2.0-litre petrol engines] is usually due to misalignment of the alternator itself
The 2.1-litre diesel engine is very common in Irish-market models and it is not without some problems:
- The EGR valve can block up and fail to work, causing an engine check light (it's expensive to replace) and the EGR system's cooler bypass valve can spring a coolant leak as well
- An unusual one that might be tricky to diagnose is the internal collapse of the intercooler outlet hose. It usually manifests itself in poor running, plus the engine check light, and shouldn't cost a fortune to remedy
- Another difficult one to work out is chafing of the wiring loom on the engine cover, causing all kinds of error codes and possibly poor engine running, too. It may be necessary to repair the loom and modify the cover
Three official recalls were carried out on this generation of E-Class, two of them issued in March 2017. The first affected cars built from October 2014 until 2016 and related to the installation of the front windscreen wiper motor, which may have been positioned too close to the wiper rod linkage. In such instances, it would damage the wiring harness of the vehicle while the wipers were in motion. A total of 988 cars were affected and the remedial work should have been carried out by now. Then, on cars built from October 2015 into 2016, the second recall affected the possibility that if the front passenger seat were adjusted to its lowest or rear-most position, it could cause a pressure hose underneath to bend. This would make the car's software erroneously identify the passenger as a child seat, meaning the airbag was deactivated. Again, this should have been sorted by now on any car you're looking at.
The final recall was only issued at the end of May 2020 and would relate to early Mk4 E-Class models, if affected. It is on all C-Class, E-Class, CLK and CLS vehicles built from January 1, 2000, until July 15, 2010, a grand total of 2,783 cars in Ireland overall, and pertains to the bonding between the glass panel and sliding-roof frame becoming less adhesive, meaning glass sunroofs could become completely detached from the vehicle.
Next section: When should I service my Mercedes E-Class Mk4?