E350 CDi coupe noisy engine

[Jamief00]

I recently purchased a 09/2009 E350 CDI Coupe with 33000 miles on the clock. Been very happy with the car, but I've noticed that when cold it is quite noisy, and even when warmed up under load it does make quite a bit of noise (moderate acceleration). Also my fuel economy isn't great - a mixed drive into work of 5 miles returns 25mpg (not particularly slow traffic, and mostly flat). On a run, driving very carefully I've hit 40mpg but no more.

I know there were some issues with injector mapping on early 350CDIs, should this have been fixed? And if so, how would I tell?

 

[This is Pete]

Mine tends to growl a bit when being fed some beans. But I've not noticed excessive noise when cold.

Personally, I wouldn't expect very much in the way of fuel economy on short, cold journies, but I don't know if 25mpg is to be expected.

As for the injectors, you'll need to refer to the service history. MB should have it all electronically stored. As them about it, and they should be able to tell you.

 

[Jamief00]

Thanks for that - I'm not sure if the noise I'm experiencing is usual or not. On the run in to work today I got 28.9mpg at the end of the journey, the car was driven from cold though. Maybe this is to be expected given that the journey is only ~5 miles or so.

If anyone knows the Tech Bulletin for the injector fix I'll phone MB and see if its been done.

 

[blue gnome123]

At 5 miles a big diesel is probably just warmed, that why (Mrs BG's 5 mile commute) we bought a petrol. Plus you may have DPF issues in the future with constant urban use like that. I'm not surprised either that you are seeing fuel economy in the 20's with this use.

 

[Jamief00]

My commute is 5 miles each way, but that certainly isn't the extent of my driving, so I have no concerns about the DPF whatsoever. I regularly drive cross country to the west coast, and go on a long drive each weekend.

 

[developer]

We're a friendly bunch on here - if you declared your location then you may be able to compare with another on here - it will help, whether the outcome is good or bad.

 

[blue gnome123]

Hi I'm glad to see that you give the car a long drive often (not clear from OP) since it would be a shame to not use the car as they are best intended. Numerous cars have DPF problems with diesels. Although compared to the Honda forum I lurk on there are very few posts on DPFs.

40mpg when driving is not great. I drive to my office 1-2 twice a week, 98mile each way, 95% m-way or fast A road and I often see +40mpg. That's certainly not hanging around either, although my S211 is 2008 and no DPF.

 

[This is Pete]

40mpg is economical for a E350 CDi. 35mpg is good for me. It took me 90miles of slipstreaming lorries at 50-55mph to get up to 47mpg.

 

[snoop51]

On my commute from Colchester to Ramsgate sitting on cruise control at around 70 I get about 42mpg. I have had 47mpg once sitting dead on 70 on a balmy day on a journey which involved starting 200yards from the M25 Heathrow junction around to the M2 exit. I have never achieved that figure since! They are a bit more rattly in cold conditions as we are having now and they certainly growl if you are giving it the beans. I used to do a 10 mile commute and used to see 32 - 33mpg regularly, they aren't the most economical but then would you expect a 3 litre diesel to be so? If economy was your main objective surely you would have been better with a 220cdi or even (strike me down) a BMW 520d

 

[Jamief00]

I don't think I said economy was my main objective?

I was merely questioning the mpg I was seeing - I've seen better from an A5 3.0TDI which has quattro!

 

[Merc Owner 2B]

Mine has done 28,000 miles now and is certainly a bit noisier than when new. But only a bit.

26 mile daily commute, average 40-50 mph returns 37 mpg and long runs (100 miles plus on motorways) will give about 44-45 mpg. Did get 47 once but that was driving carefully during the fuel shortages last year!

 

[snoop51]

What car comparison
Audi A5 3.0tdi quattro Average mpg 49.6 town 41.5 out of town 55.4
BMW 530d se 49.6 38.2 60.1
MB E350CDI BE coupe 47.1 38.7 57.6

Those are all official figures which as we all know in real life is about as achievable as getting a politician to actually carry out what they say they will. I take your point about economy not being the main driver for your purchase but you've picked a car which has lower official around town figures than the Audi and which has the lowest average of the three. The real life figures are much lower and the only reason I manage 40 - 42mpg on my commute is that I choose to drive early in a morning and before the evening traffic builds up.

 

[This is Pete]

Unfortunately, I have no info on the injector issues. A call to your MB service department should put you on the right track.

 

[Jamief00]

Thanks for the replies - I'll give them a call.

I tend to take official figures with a shipload of salt (i.e. disregard them altogether!). A friend has an A5 3.0TDI Quattro, which is why I made the comparison. If anything, you'd expect the extra weight on the E350 would be negated by the AWD lossed on the A5 and they'd have similar around-town figures, especially given the low drag coefficient on the E350, but seemingly not! Ach well, at the mileage I do I don't really care!

 

[This is Pete]

Well, at least we've reassured you that the mpg you're seeing is largely to be expected.

You're probably the same as the rest of us E350 CDI owners in not buying the car for it's economy; if we did, we'd all be driving E220/E250 instead.

 

[st4]

Well, at least we've reassured you that the mpg you're seeing is largely to be expected.

You're probably the same as the rest of us E350 CDI owners in not buying the car for it's economy; if we did, we'd all be driving E220/E250 instead.

If you didn't buy the car at all for economy why didn't you buy a 500 or AMG?

 

[This is Pete]

If you didn't buy the car at all for economy why didn't you buy a 500 or AMG?

I prefer the smell of diesel.

 

[Jamief00]

If you didn't buy the car at all for economy why didn't you buy a 500 or AMG?

Because the E500 Coupe has fairly poor reviews, and there isn't a E AMG coupe?

And also there is a huge difference between "not buying for economy" and "not caring about economy"!

 

[wilsodg]

I had a similar dilemma to the OP - moving from a 430 210 estate to a 212. Need occasional towing, so 63 was not an option. The dealer really worked hard to steer me away from the 500 - which was what I walked into the showroom to buy (economy and depreciation - no he didn't sell me a stock alternative), the performance of the 350sport seemed ok (on a par with the 430), and the fuel figures tipped the balance. I'm pleased with the 350 but it doesn't feel as responsive as the 430 did and for a while the economy worried me - after 6k miles it's averaged 31 and I drive it more sedately than the 430 where I averaged 23. I'm not so worried about the consumption other than MB quote a number at least 35% more than I am getting and one wonders if there is a problem. Apparently not, it's a game MB play. On balance though, the 500 might be a better bet if you want performance, and if you want economy, buy a 250 diesel..

 

[johny5_uk]

I rejected my 59 E350 coupe after nearly a year of repeated visits to Mercedes for a noisey (knocking/rattling) engine and poor economy.
I used to go in nearly every month for them to reset the injector values which fixed the fault for a few hundred miles but then it returned soon after!
It was never permanently fixed but my new 11 coupe doesn't suffer with this.

They loaned me a same year E350 saloon with same engine and I seem to recall managing to get about 9 mpg more on a 250 mile commute. It was hilarious as the book figures show that the coupe was more economical.

I hope you get it sorted, if they say there aren't any upgrades then I would ask them to reset the injectors to start.