"Is the S Serisi S400 reliable, and what should you check?"
The most frequently mentioned issue when buying a used Mercedes-Benz S-Class S400 2016 (217 / 222): Oil leaks from cylinder head plugs and gaskets. Also, Ignition Misfires: Ignition Coils, Injectors and Sensors are commonly reported.
Engines available in this year
Engine varies by trim; verify the engine code on the listing.
M276.824
turbo petrol · S400 · S 400 V6 (333 bg) 4MATIC 7G-TRONIC PLUS
M276.960
turbo petrol · S400 · S 400 (333 bg) HYBRID 7G-TRONIC
Known issues and risks
Listed from most frequently reported, each with its source.
Oil leaks from cylinder head plugs and gaskets
Often reported
A frequently reported issue is oil leaks around the plastic cylinder head plugs and valve cover gaskets. Over time, these parts can harden or crack, causing visible leaks and sometimes smoke or a burning oil smell.
Engine Bay
Ignition Misfires: Ignition Coils, Injectors and Sensors
Often reported
Over the years, misfires due to worn ignition coils, faulty spark plugs/injectors, or sensors (e.g., MAF, lambda) are common; this leads to a check engine light, rough idle, and power loss.
Engine Internal
Oil consumption and risk of cylinder damage
Often reported
Many users and technical reports indicate higher than normal oil consumption in high-mileage vehicles; if left unchecked, it can worsen cylinder wall wear or 'cylinder scoring', especially when combined with intake manifold deposits.
Engine Internal
Timing chain and gear wear
Often reported
In the M273 V8 engine, the timing chain, tensioners, and gears can wear prematurely; this can cause rattling noise, a check engine light, and timing loss.
What should I look for when buying a Mercedes-Benz S-Class S400?+
When buying a 2016 S400, check the service history, take a test drive, and look for engine/transmission warnings. The most commonly reported issues: oil leaks from cylinder head plugs and gaskets; Ignition Misfires: Ignition Coils, Injectors and Sensors; oil consumption and risk of cylinder damage.
What are the chronic problems of the Mercedes-Benz S-Class S400?+
The most commonly reported issues: oil leaks from cylinder head plugs and gaskets; Ignition Misfires: Ignition Coils, Injectors and Sensors; oil consumption and risk of cylinder damage.
Is the Mercedes-Benz S-Class S400 reliable?+
Rather than a simple yes/no, it is better to weigh the proven pros and cons together. This page lists 4 verified findings.
How does Carbeak collect data?+
The cards on this page are derived from the Difetti fault database; the source vehicle is matched to the target vehicle by brand, fuel type, engine, and generation. Topics with insufficient evidence are not shown.