Are the Current 2.1 Diesel Engines Reliable?

[Bryce]

Hi,
To give some context, I have Driven E class Estates since 1984. S123, 124, 210, 211, & 212s . I always went for the bigger Diesel engines, 3l straight six and latterly the V6.
Now on looking for the latest replacement, hopefully a 18 or 19 plate, I find my choice of engine is different and the E350 has a 2.1 unit. I have no experience of these engines and would like some input as to their reliability and quirks they may have.
As it’s likely to be my last car, I want to choose carefully. I would like to hear what experiences existing users have had ( Good and Bad). Thank You. Bryce

 

[cws196]

The e350d is still a 6cyl, only inline 6 now and no longer V6. My dad recently bought a used GLE350d (same engine) so I went all through the known issues - main thing you have to watch out for on this engine (OM656) are failing coolant/brake-vac pumps. The pump seals start to fail which first manifests in worsening brake performance but then leads to oil contamination in to the brake-vac system and coolant leaking in to the engine oil system (leading to sludging). The worse thing is the pump is buried in the middle of the engine and it's engine out/head off, plus MB don't want to know after the 3years warranty is expired (unless you have an MB used warranty). On the plus side a car of 2018-19 age would likely have had the issue arise already and MB did issue a TSB software update to switch one of the pump valves to being one-way only to prevent coolant ingress. A simple check is to locate the brake vac servo, remove the vac pipe and dip in a pipe cleaner etc - any signs of oil then walk away. Other than that no major known issues on the OM656.

The OM656 is essentially the 4 cyl/2L OM654 with 2 extra cyclinders bolted on - it seems a better engine than the OM654 (which have suffered cam rocker arm wear). Also to note is the AdBlue system reliability has improved as the everything is now housed closer to engine block, resulting in faster warm-up.

 

[Petrol Pete]

From what I have seen on here over the years you would probably be better off sticking with an older Mercedes Benz , especially if looking at the newer Diesel models .

 

[W1ghty]

Hi,
To give some context, I have Driven E class Estates since 1984. S123, 124, 210, 211, & 212s . I always went for the bigger Diesel engines, 3l straight six and latterly the V6.
Now on looking for the latest replacement, hopefully a 18 or 19 plate, I find my choice of engine is different and the E350 has a 2.1 unit. I have no experience of these engines and would like some input as to their reliability and quirks they may have.
As it’s likely to be my last car, I want to choose carefully. I would like to hear what experiences existing users have had ( Good and Bad). Thank You. Bryce

What mileage do you do for the diesel need buddy ?
I think generally avoid any modern diesel with adblue .

 

[Bryce]

What mileage do you do for the diesel need buddy ?
I think generally avoid any modern diesel with adblue .

Thank you. My mileage is much reduced now I am retired so Petrol is probably my best bet, but I’m finding them to be very scarce too. It’s more habit than anything else that I always go for the diesel. And yes Adblue scares me. The newest ones that I can find are 16 and 17 plates but they nearly all have more miles on them than my 2012. S212 265BHP. Thanks

 

[W1ghty]

Thank you. My mileage is much reduced now I am retired so Petrol is probably my best bet, but I’m finding them to be very scarce too. It’s more habit than anything else that I always go for the diesel. And yes Adblue scares me. The newest ones that I can find are 16 and 17 plates but they nearly all have more miles on them than my 2012. S212 265BHP. Thanks

Audi and BMW do quite a lot of petrol engine cars .

 

[Smart320]

Better the devil you know

 

[markjay]

..the AdBlue system reliability...

 

[fabes]

Is it an E class you are after?

Recent C class petrols are about as are (and left field suggestion) hybrid A250e hatchbacks and saloons in plentiful numbers