Pure Speculation: M272 Engine Reliability vs. M276

[voy2k]

Hi All- A couple months ago, before there was any solid information on the MY2012 E class, I ordered an E350. The car has arrived in NY and is making its way to Southern California and now I am seriously torn on whether to go with this car or wait for the MY2012. This is all based on the assumption (not confirmed but seeming likely) that the 2012 E350 will have the new M276 direct injection engine. The added HP really isn't that important to me, but the increased fuel efficiency and apparent overall improved efficiency of the next-generation engine are attractive. it really comes down to reliability so I'm going to ask the experts here to do some blind speculation on the M272 (current engine) vs. the M276 (new engine). There have certainly been issues with the M272-- There's a class-action lawsuit re: defective balance shift gears in this engine and my sister-in-law has a 2006 E350 that she had a lot of engine problems with (covered under warranty.) But it seems like Mercedes has refined their way through these issues and that, at the end of its lifecycle, the M272 is a very solid, reliable engine in the E350. Will the M276 be reliable? I asked my independent Mercedes mechanic about it. He wasn't specifically aware of this engine (he's more trailing edge, working on cars that are coming out of warranty), but when I described the basic architecture his comment was, "They're getting the added HP from extremely high compression ratios-- if and when this engine starts to break, it will be expensive to fix." I'm planning to keep this car for its full life, so reliability will be very important. I understand there is no way to know for sure, but I'd love to hear your thoughts on this. I was pretty well set to wait for the 2012, but now that the car I ordered has arrived in the States, I'm getting 'bird in the hand' syndrome. Hopefully Mercedes will have some definitive news re: the 2012 Es at the New York Auto Show later this week. In the meantime, any input is appreciated. Thanks, Voy

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[ImInPA]

Originally Posted by voy2k

Hi All-

A couple months ago, before there was any solid information on the MY2012 E class, I ordered an E350. The car has arrived in NY and is making its way to Southern California and now I am seriously torn on whether to go with this car or wait for the MY2012.

This is all based on the assumption (not confirmed but seeming likely) that the 2012 E350 will have the new M276 direct injection engine. The added HP really isn't that important to me, but the increased fuel efficiency and apparent overall improved efficiency of the next-generation engine are attractive.

it really comes down to reliability so I'm going to ask the experts here to do some blind speculation on the M272 (current engine) vs. the M276 (new engine).

There have certainly been issues with the M272-- There's a class-action lawsuit re: defective balance shift gears in this engine and my sister-in-law has a 2006 E350 that she had a lot of engine problems with (covered under warranty.) But it seems like Mercedes has refined their way through these issues and that, at the end of its lifecycle, the M272 is a very solid, reliable engine in the E350.

Will the M276 be reliable? I asked my independent Mercedes mechanic about it. He wasn't specifically aware of this engine (he's more trailing edge, working on cars that are coming out of warranty), but when I described the basic architecture his comment was, "They're getting the added HP from extremely high compression ratios-- if and when this engine starts to break, it will be expensive to fix." I'm planning to keep this car for its full life, so reliability will be very important.

I understand there is no way to know for sure, but I'd love to hear your thoughts on this. I was pretty well set to wait for the 2012, but now that the car I ordered has arrived in the States, I'm getting 'bird in the hand' syndrome.

Hopefully Mercedes will have some definitive news re: the 2012 Es at the New York Auto Show later this week. In the meantime, any input is appreciated.

Thanks,
Voy

As you state...it all boils down to reliability. If that is indeed your primary concern, then, the current engine is a known entity and rock solid. It has the power you need. There is no reason to think the new engine will be less reliable, but, it is an unknown. Enough said.

[BudC]

First of all, the projected improvement in fuel mileage is attributed to more than just direct injection. There is the start/stop feature, there is lean burn (not coming to the U.S. because of the poor quality fuel here), there are changes to things like the oil pump, water pump and a couple of other things. In other words, don't count on a significant improvement in U.S. version engines.

The new engine is a 60 degree engine which is good because it's naturally balanced and doesn't require a balance shaft (although it will still have an idler gear the same as the V8).

Direct injection has been known to contaminate the oil supply some amount. I read an article by an engine builder who said he changes oil at 5K intervals because of it.

I wanted a new V8 so I have a 2011 E550 at the VPC in Long Beach right now. I wanted no part of the new bi-turbo charged, direct injected engine coming in 2012. The Current M 273 has been characterized as one of the smoothest running engines on the planet and it's a proven design. In my case, the choice between the 2011 and the 2012 engines was simple.

[petee1997]

Most of the improvements in fuel efficiency come from the stop and start function of the new car. The gains are in stop and go traffic otherwise the mileage gains are small. However there will be a cost in battery and starter replacements.
DI engines have not been without problems. Check out BMW and Porsche. Both have had issues the first year. Maybe MB has a better mouse trap but history would suggest there will be problems in the beginning.
If you are in doubt just because of fuel efficiency, get the diesel, that should give you 25% better fuel efficiency.

[BPhillyBenz]

All good points Boys. I have been burned too many time on Year 1's. With that said, if the reviews end up A+++, I would switch over. Until then, I happy were I am.

[scfishnman]

Just an opinion, but i would stick with the proven engine rather than gamble on a first year new design. Since the styling and overall features of the car will not change, just the engine, I would be even more inclined to go with the 2011.

[Wig]

Originally Posted by scfishnman

Just an opinion, but i would stick with the proven engine rather than gamble on a first year new design. Since the styling and overall features of the car will not change, just the engine, I would be even more inclined to go with the 2011.

I may be wrong here, but isn't the M276 already in use in other Benz models? It will have had at least some real world testing before it arrives in the US/Canada.

I also believe that the good reliability of the first model years of the W204 (2008) and W212 (2010) shows that Mercedes is taking its quality control more seriously. Hopefully we can expect the M276 to be reliable from the outset.

[voy2k]

Yes, the M276 has been in use in the UK and India (possibly other markets as well), so it is indeed getting real-world testing. My understanding is that the M276 is the high-volume engine going forward, so it will certainly have support.

Everyone, the input here has been absolutely brilliant. I half-expected to get run out of here because I keep bringing up the MY2012 to a bunch of people who already have earlier models Your willingness to share thoughts on this subject is greatly appreciated.

Because reliability will truly be my biggest concern, your thoughts have me leaning towards the 2011, but the deliberation continues. I'd love to hear any other input that anyone has.

- Voy

Originally Posted by Wig

I may be wrong here, but isn't the M276 already in use in other Benz models? It will have had at least some real world testing before it arrives in the US/Canada.

I also believe that the good reliability of the first model years of the W204 (2008) and W212 (2010) shows that Mercedes is taking its quality control more seriously. Hopefully we can expect the M276 to be reliable from the outset.

[BudC]

Originally Posted by Wig

I may be wrong here, but isn't the M276 already in use in other Benz models? It will have had at least some real world testing before it arrives in the US/Canada.

I also believe that the good reliability of the first model years of the W204 (2008) and W212 (2010) shows that Mercedes is taking its quality control more seriously. Hopefully we can expect the M276 to be reliable from the outset.

Even if the engine has been used in other countries, there are still things to consider such as differences in the quality of fuel. More than one source claims that the lean burn feature of the new engines won't make it to the U.S. because of the relatively high sulfur content of U.S. fuels and not just the stuff from South America but all of it.

BMW's V8 appeared in other countries but when it was imported into the U.S., high sulfur fuels purchased at discount outlets caused cylinder wall etching. BMW had to install new short blocks in those engines.

As for the W212's being problem free, see Konigtiger's posts about known problems. You simply cannot test every possible situation, not even with computers. The best tests are done by consumers so that's why you want to avoid leading edge wind burn by letting someone else test the early entries.

[ImInPA]

Originally Posted by voy2k

Yes, the M276 has been in use in the UK and India (possibly other markets as well), so it is indeed getting real-world testing. My understanding is that the M276 is the high-volume engine going forward, so it will certainly have support.

Everyone, the input here has been absolutely brilliant. I half-expected to get run out of here because I keep bringing up the MY2012 to a bunch of people who already have earlier models Your willingness to share thoughts on this subject is greatly appreciated.

Because reliability will truly be my biggest concern, your thoughts have me leaning towards the 2011, but the deliberation continues. I'd love to hear any other input that anyone has.

- Voy

Then you have answered your own question. Buy the 2012 if it has the new engine. In all honesty, the difference in hp will yield an acceleration improvement measured in tenths of a second and likely not more an one or two tenths of a second.

[Wig]

Originally Posted by BudC

Even if the engine has been used in other countries, there are still things to consider such as differences in the quality of fuel. More than one source claims that the lean burn feature of the new engines won't make it to the U.S. because of the relatively high sulfur content of U.S. fuels and not just the stuff from South America but all of it.

BMW's V8 appeared in other countries but when it was imported into the U.S., high sulfur fuels purchased at discount outlets caused cylinder wall etching. BMW had to install new short blocks in those engines.

As for the W212's being problem free, see Konigtiger's posts about known problems. You simply cannot test every possible situation, not even with computers. The best tests are done by consumers so that's why you want to avoid leading edge wind burn by letting someone else test the early entries.

All fair points.

I would hope that Mercedes would comprehensively test the new engines with a variety of North American fuels, thus avoiding BMW's mess. At the end of the day I agree that real world testing finds problems that the manufacturer may not have found.

Also, I don't think anyone has said the W212 is problem free, but its reliability has been acceptable so far.

[ImInPA]

Other than a couple interior sounds, my E350 BlueTEC has been flawless. (and the interior noises have been fixed). No car is perfect. At the peak of Honda's "the car that sells itself" years, I bought a Prelude with the 4 wheel steering. An amazing car for the time. One day the entire rear suspension and sub frame disconnected from the car. It was probably the only Prelude that ever had such an issue. You just never know.

[RJC]

Go drive an '11 CL 550 (it has the new TT DFI) I did and I'm now torn between which is the better of the V8's.

[K-A]

Common sense will say two things: 1- the M276 is gonna be a new engine, while the M272 is in its last year, and has been as refined as it's gonna get. 2- The M276 is a more complex engine, with more things that can go wrong. Very high compression and D/I means that you have two things that can be volatile to an engines longevity. That said, as long as M-B makes the thing flawlessly, it should hold up great. But the M272 has "less that can go wrong", one would think, at this time.

I too could really care less about the HP, but sure, I'll take it if it's there, however two things that the new engine can provide that would make me upset about mine are: Improved smoothness (the current motor is very smooth, but the smoother the better), and if the MPG increases relatively dramatically. The HP isn't a big issue, but it's kind of a slap in the face to get worse gas mileage with the less power. Main thing going for the M272 over the M276 is potentially less fussy ownership experience, and a potentially more reliable worry-free motor.

[voy2k]

Originally Posted by K-A

Common sense will say two things: 1- the M276 is gonna be a new engine, while the M272 is in its last year, and has been as refined as it's gonna get. 2- The M276 is a more complex engine, with more things that can go wrong. Very high compression and D/I means that you have two things that can be volatile to an engines longevity. That said, as long as M-B makes the thing flawlessly, it should hold up great. But the M272 has "less that can go wrong", one would think, at this time.

I too could really care less about the HP, but sure, I'll take it if it's there, however two things that the new engine can provide that would make me upset about mine are: Improved smoothness (the current motor is very smooth, but the smoother the better), and if the MPG increases relatively dramatically. The HP isn't a big issue, but it's kind of a slap in the face to get worse gas mileage with the less power. Main thing going for the M272 over the M276 is potentially less fussy ownership experience, and a potentially more reliable worry-free motor.

Good points K-A.

My impression is that, without the lean-burn or start/stop functionality, the fuel efficiency improvements for the M276 vs. the M272 will be fairly modest. I forgot to mention that my independent MBZ mechanic actually owns a 2008 E350 (and loves it)-- he said he took a trip to Las Vegas a couple months ago and got 28 MPG on the trip (averaging about 80 MPH). If I get that kind of mileage on my 2011 E350, I can live with that.

So assuming that the MPG between the two engines will not be appreciably different (perhaps a big assumption-- we'll have to see), then it comes down to the extra HP. As noted, this isn't a big factor for me.

Reading everyone's input has really solidified that reliability is my biggest factor. The new engine, while attractive in many ways, introduces risks that simply aren't quantifiable at this point. I'm still hoping to get news from MBZ on the 2012s very soon (to see if the M276 is even a reality), but I'm leaning towards the 2011 at this point.

- Voy

[CynCarvin32]

Two Points:

1) We are talking about longevity here I see but lets be realistic. Do you ever see any MB have an internal motor failure (without modification) anywhere below 150-200k miles (and a failure on engine internals at that point is still very rare if serviced). So if the people deciding between the two motors do not plan to put 200-250k miles on the car the longevity difference is minimal. The 272 motor had issues with cam position sensors going bad and some other small issues but none of them reduce the longevity of the motor.

2) As far as smoothness of the 276 vs the 272 I would say the new motor will be smoother. The current 3.5L motor is not exactly the smoothest motor in the segment. At low RPM it is ok but when being reved it is pretty coarse. In the W212 its fairly decent since it has very well designed isolation systems but in a car like the R and ML class cars it is pretty rough and crude.

I would wait for the new motor since the segment left the 272 motor behind in about 2007 and it makes well less power than 25-30k ford mustang v-6's. Also the 272 gets absolutely inexcusable fuel mileage. On the open road (Los Angeles to San Francisco for example) it barely manages to get 25 mpg. When you consider that my E63 gets 22 mpg regularly the V6 seems quite thirsty. BMW, Cadillac, Lexus and everyone else seems to have a more efficient V6 that makes well more power. Around town the E350 gets 13 mpg and that is just sad.

[BudC]

Originally Posted by CynCarvin32

Two Points:

Around town the E350 gets 13 mpg and that is just sad.

I just sold a 2008 E350 and the computer had it getting 18.6 MPG for the last 6,000 miles. Every bit of this was city driving. When I bought the car, we took it on a 6,000 vacation when it had only 200 miles on the clock. Comparing real mileage based on total fuel usage for the trip versus the computer, the computer was optimistic by 1 MPG. There were days when I did almost all Interstate driving and the computer reported an average of 28 MPG.

I don't use cruise control because it won't produce the mileage you can get without it. Cruise control will try to maintain a constant speed going up and down hills. This will waste fuel.

I generally drive slightly above posted speed limits.

[voy2k]

Originally Posted by BudC

I just sold a 2008 E350 and the computer had it getting 18.6 MPG for the last 6,000 miles. Every bit of this was city driving. When I bought the car, we took it on a 6,000 vacation when it had only 200 miles on the clock. Comparing real mileage based on total fuel usage for the trip versus the computer, the computer was optimistic by 1 MPG. There were days when I did almost all Interstate driving and the computer reported an average of 28 MPG.

I don't use cruise control because it won't produce the mileage you can get without it. Cruise control will try to maintain a constant speed going up and down hills. This will waste fuel.

I generally drive slightly above posted speed limits.

Thanks for the real-world numbers Bud. These match up pretty closely with the EPA numbers.

Realistically, most people probably aren't buying an E-class for the fuel economy, but I would hope that the mileage would be reasonable and I think this is.

[K-A]

Originally Posted by CynCarvin32

Two Points:

1) We are talking about longevity here I see but lets be realistic. Do you ever see any MB have an internal motor failure (without modification) anywhere below 150-200k miles (and a failure on engine internals at that point is still very rare if serviced). So if the people deciding between the two motors do not plan to put 200-250k miles on the car the longevity difference is minimal. The 272 motor had issues with cam position sensors going bad and some other small issues but none of them reduce the longevity of the motor.

2) As far as smoothness of the 276 vs the 272 I would say the new motor will be smoother. The current 3.5L motor is not exactly the smoothest motor in the segment. At low RPM it is ok but when being reved it is pretty coarse. In the W212 its fairly decent since it has very well designed isolation systems but in a car like the R and ML class cars it is pretty rough and crude.

I would wait for the new motor since the segment left the 272 motor behind in about 2007 and it makes well less power than 25-30k ford mustang v-6's. Also the 272 gets absolutely inexcusable fuel mileage. On the open road (Los Angeles to San Francisco for example) it barely manages to get 25 mpg. When you consider that my E63 gets 22 mpg regularly the V6 seems quite thirsty. BMW, Cadillac, Lexus and everyone else seems to have a more efficient V6 that makes well more power. Around town the E350 gets 13 mpg and that is just sad.

Good and interesting points, but the MPG is off. I have had 2 E350's (W211 and W212), and my W211 would get up to 29 MPG in ideal conditions on long drives (Computer), and my W212 can pass 28 MPG in good conditions and on long drives. I get 24-25 MPG on long trips only when the wind is drastically blowing toward the car. I will say, that my 212 isn't getting as good MPG as my W211 did, which is odd, as it's rated better. I hopefully credit this to the motor not being broken in enough yet (under 8K Miles).

I certainly didn't buy my car for MPG, but I also certainly don't want a thirsty car, unless it's pushing 500 HP. I haven't been too impressed with my cars MPG yet, but we'll see how it does since Summer Gas Blend is back, and the motor is more broken in.

[ImInPA]

The E350 BlueTec has a great engine. For the past 9K miles my overall avg. mg is 33.2 (according to the trip computer). Running around on weekends I see between 28-31 mpg. On the Highway, the lowest I have seen is 31 and the highest 42. Phenominal by any measure for a 4200 lb. car. It is noticeably quicker now that it has a few miles on it too.