The 4 Typical Mercedes M276 Engine Issues. Mercedes-Benz’s M276 engine is the successor to the preceding M272 engines. Because Mercedes was controlled by FCA at the time, it is also related to the Fiat-Chrysler 3.6L Pentastar V6 engine. Mercedes also provides three M276 variants: a 3.5L NA, a 3.0L twin turbo, and a 3.5L twin turbo. They’re all excellent choices that provide a nice blend of performance and efficiency. However, no engine is perfect, and there are no exceptions here. This page discusses some typical issues with the Mercedes-Benz M276 V6 engine as well as general reliability.
Engine Options for the Mercedes M276
Before we get started, it’s necessary to understand the distinctions between the M276 engines. The engines in the M276 family are all discussed in this page. However, some of the concerns we mention may have a greater impact on particular variations than others. We’ll clarify as needed in the article. For the time being, let’s lay out the variants and present a list of vehicles that employ each engine.
M276 DE 35 3.5L NA Mercedes
The original M276 DE 35 engines offer 3.5L in a 60° V6 configuration. They’re naturally aspirated, but they also have direct injection and a high-pressure fuel system. This is a revolutionary technology that helps increase fuel efficiency, emissions, and performance in V6 Mercedes engines. M276 DE 35 engines produce 248 to 302 horsepower, which is extremely good for a NA engine. It is available in the following Mercedes-Benz models:
- 2011-2014 W218 CLS350
- 2011-2016 W212 E300
- 2012-2016 W212 E350
- W212 E400 Hybrid 2012-2016
- 2011-2014 W204 C300
- 2011-2014 W204 C350
- 2012-2015 W166 ML350
- 2012-2015 X204 GLK350
- 2010-2013 W221 S350
- W222 S400 Hybrid 2013-2017
- 2011-2015 R172 SLK350
3.0L M276 DE 30 LA Twin Turbo
Mercedes brought the M276 to a new level in 2013 with a smaller twin turbo configuration. It is built on the same engine family and platform as the DE35 normally aspirated engine. To support the turbo boost pressure, compression is reduced from 12.2 to 10.7. Two IHI turbos provide quick spool and little turbo lag, allowing the M276 DE 30 to produce 328 horsepower and 354 lb-ft of torque.
In 2017, a high-output variant appeared with an even more amazing 362hp and 384tq. A third modification in 2019 permits the most recent M276 DE30 engines to produce 385hp and 384tq. The Mercedes-Benz DE 30 LA is available in the following trim levels:
- 2013-2016 W212 E400
- 2016-2018 W213 E400
- 2019-2020 W213 E450
- 2014-2017 W218 CLS400
- W205 C400 from 2015 to the present
- 2015-2017 W205 C450
- S500 Plug-in Hybrid (2014-2017)
- 2018-2020 W2200 S560 e
- X166 GL450 / GLS450 2014-2019
- 2015-2017 W166 ML400
- W166 GLE 450 / GL 550 e 2016-2018
- W166 GLE 43 AMG 2015-2019
- X253 GLC 43 AMG from 2015 till the present
- W205 C 43 AMG (2016-present)
- 2016-2018 W213 E 43 AMG
Twin Turbo 3.5L V6 DE 35 LA
M276 DE 35 LA engines are quite identical to the original NA type in terms of displacement, bore x stroke, and so on. The main difference, of course, is the installation of twin turbos. It is intended to deliver the same performance as the Mercedes 3.0 twin turbo V6 (328hp and 354tq). The goal of the displacement increase is to run lower turbo boost. Despite its increased size, this improves efficiency. DE35LA engines are used in the following models:
- 2013-2017 W222 S400
- 2015-2017 Maybach S400 W222
4 Common M276 Engine Issues
Some of the most prevalent issues with Mercedes M276 V6 engines are as follows:
- HPFP
- Carbon accumulation
- tensioner for the timing chain
- Coils and plugs
We’ll go over the points raised above in further detail over the rest of the essay. However, now is a good opportunity to make a few quick remarks. The M276 engines are all fairly reliable. For good reason, we’ve classified them as the most common issues. It does not necessarily imply that they are widespread problems affecting a large proportion of Mercedes M276 engines. Rather, when difficulties arise, they are some of the most typical places.
As previously stated, the M276 is available in several variations, including the DE35 NA, DE30 twin turbo, and DE35LA twin turbo. We’ll determine whether a problem affects specific M276 engines more than others. Another factor to consider is that twin turbo engines provide more performance and tuning options. However, turbo M276 engines are often more expensive to service than NA DE35 engines.
**We may refer to the several M276 engine variations (for example, M276 DE 30). Unless otherwise specified, it applies to all M276 engines.
1) Mercedes-Benz M276 HPFP Troubleshooting
The Mercedes M276 V6 uses a high-pressure fuel system as a direct injection (DI) engine. The high pressure fuel pump (HPFP) is in charge of supplying gasoline at extremely high pressures to the direct injectors. Failures of HPFPs are not unheard of. BMW encountered numerous problems with the N54, its first mass-production turbo DI engine. VW had a number of issues early on as well.
HPFP failures on the Mercedes M276 are far less prevalent than the latter occurrences. However, HPFP issues on Mercedes M276 engines can and do occur. As some of the early engines age, it appears that more and more examples are emerging. Anyway, while this is far from a typical occurrence, it is something to be aware of.
When the Mercedes V6 high pressure fuel pump fails, you will notice a number of symptoms. Fortunately, the M276 HPFP rarely dies abruptly, but rather over a period of months or even years. Some experience problems as early as 30,000 miles, however most HPFP failures occur beyond 80,000 miles.
M276 HPFP Failure Symptoms
Look for the following signs that may indicate a problem with your Mercedes M276 V6 HPFP:
- Long cranking
- Engine error codes / CEL
- Stuttering or hesitancy
- Idle time
- Power outage
An excessively long crank, especially on cold starts, is one of the earliest symptoms of HPFP failure. Of course, many other factors might contribute to long cranks on the M276 engine, so don’t forget the fundamentals. Otherwise, when HPFP faults worsen, you’ll notice more and more drivability issues.
As the HPFP worsens, common symptoms include stuttering, reluctance, harsh idle, and power reduction. Finally, a check engine light and fault codes should illuminate, indicating that the fuel pump isn’t keeping up with the appropriate flow and pressure.
HPFP MB M276 V6 Replacement
Again, when compared to the troubles of some other DI systems, HPFP aren’t all that common on the M276. Another piece of good news is that the M276 fuel pump is reasonably priced, ranging between $300 and $600. It’s also not a difficult repair for the do-it-yourself set, but labour can pile up for the repair shop crowd.
2) Carbon Build-Up Issues on M276
Another intriguing aspect of direct injection is carbon buildup. All engines produce some natural oil blow-by, which enters the intake ports. Traditional port injection (PI) sprays fuel into the intake ports. This aids in the removal of any oil deposits that have accumulated on the intake ports and valves. DI, on the other hand, sprays fuel directly into the cylinder, leaving nothing to remove any deposits.
In the preceding section, we discussed the N54 engine and VW/Audi. Excess carbon build-up occurred in such engines as early as 40,000 to 60,000 kilometres. Mercedes-Benz fared much better with its M276 V6 engine. Some argue that carbon buildup isn’t a problem at all. The separator and PCV system do a good job of minimising carbon deposits. With nothing spraying over the intake ports, however, carbon buildup occurs.
When exactly this will cause problems is unknown. We believe that when more M276s exceed 100,000 miles, carbon build-up will become a bigger issue. In the broad scheme of things, it’s a small “issue,” and some M276 engines will probably run their whole careers without carbon cleaning. Excess deposits, on the other hand, might impair performance and drivability.
*The twin turbo DE35LA and DE30 are more likely to accumulate carbon than the NA DE35 M276. Increased cylinder pressures caused by boost are likely to cause increased blow-by.
Symptoms of Mercedes V6 Carbon Buildup
Some signs of excessive carbon buildup include:
- Idle time
- Stuttering or hesitancy
- Misfires
- Power outage
As carbon deposits accumulate on intake valves and ports, they begin to limit airflow into the cylinders. This causes power loss, although it’s usually difficult to observe because it happens slowly over time. As carbon deposits accumulate, you may have misfires, stuttering, and harsh idle.
M276 Carbon “Fix”
We’re quite familiar with carbon build-up and cleaning methods having come from the BMW N54 world. Walnut blasting the intake apertures is a tried and true approach. A heavy-duty shop vac and walnut medium shells are required. To access the ports and valves, the M276 intake manifold must be removed. It takes some effort to get in there, and the entire blasting process takes an hour or two.
Cleaning the M276 intake valves at a shop will cost between $400 and 600 dollars. Because walnut medium shells are inexpensive, this project may be finished for around $20 (provided you have a competent shop vac).
3) Timing Chain Tensioners MBZ M276
Some M276 engines experience chattering upon startup. Mercedes did, in fact, publish a service bulletin to address these issues. The main problem is with the timing chain tensioner and check valves. Fortunately, around 2014, Mercedes released some new parts that fixed the problem. As a result, timing chain tensioner issues mostly impact early NA DE35 M276 engines.
In any case, the M276 secondary chain tensioners do not receive adequate oil flow upon startup. This causes the rattling sounds until enough oil pressure is built up. Installing the new tensioner and check valves helps to solve the timing chain problems.
Of course, additional flaws could cause rattling and subsequent timing chain concerns. It’s not a common problem on later versions, but keep an eye out for it with earlier M276 engines. The video below may be useful for those who are suffering rattling on start-ups.
Symptoms of M276 V6 Timing Chain Tensioner
Timing chain tensioner difficulties on the Mercedes M276 engine include the following symptoms:
- Rattling
- Codes for faults
- CEL
- Ineffective operation
The tensioners’ lack of oil flow on startup is the key sign of the problem we’re discussing. In some circumstances, a faulty timing chain tensioner or other timing chain components might result in fault codes, a check engine light and poor engine performance.
Replacement of Timing Chain Tensioner
The improved tensioners and check valves are reasonably priced for the parts alone. On top of that, labour costs a lot of money. Mercedes, on the other hand, published a service bulletin for this issue, and many were covered under warranty. If you encounter this issue after the warranty period has expired, Mercedes may be ready to work with you and assist with the repair bill.
4) Mercedes M276 Ignition System Troubleshooting
Alright. In the first place, we don’t consider this a problem. Almost any engine, including the M276’s, need spark plugs and ignition coils as normal maintenance. Flaws or premature failures do occur on occasion, but they are extremely unusual on any of the M276 engines.
The primary reason for including this section is to compare the NA and turbocharged M276 V6 engines. Turbo engines consume spark plugs and ignition coils at a far higher pace than normally aspirated engines. Higher cylinder pressures, more air and fuel, and other factors all contribute to turbo automobiles wearing out plugs and coils. The lifespan is most likely half that of NA engines. This is particularly true when tuning and modding the M276 DE30 or DE35LA dual turbo engines.
In any case, plugs and coils aren’t major issues with the M276 engine. It does emphasise the fact that turbo engines can be more difficult to maintain. There are also other things to consider with turbo engines, such as having more parts that could fail. We adore turbo engines and would take the Mercedes 3.0 or 3.5L twin turbo engine over anything else. It’s just something to think about for folks who aren’t familiar with turbo engines.
Symptoms of M276 3.0 & 3.5 Plugs & Coils
The following are some signs that indicate it is time to replace the Mercedes M276 spark plugs and/or ignition coils:
- Misfires
- Idle time
- Power outage
Misfires are usually the first clue that it’s time to replace spark plugs and ignition coils as they wear down. If they are not replaced immediately, they will continue to deteriorate, perhaps resulting in power loss, harsh idle, and other symptoms.
V6 Mercedes Plugs and Coils Replacement
On most engines, including the Mercedes V6 M276, ignition coils and spark plugs are simple to change. Even inexperienced DIYers can complete the process reasonably effortlessly. A set of spark plugs will cost between $60 and $100, while ignition coils will cost between $200 and $300.
The plugs of the M276 DE35 should last roughly 70,000 miles, and the ignition coils twice that. The turbo M276 DE30 and DE35LA will most likely require plugs every 50,000 miles or sooner, and coils will last almost twice as long.
Related : The Four Most Common GM 2.4L Ecotec Engine Issues
Engine Reliability of the M276
How trustworthy is the Mercedes M276 V6 engine? For dependability, we’ll offer the M276 ordinary to above-average ratings. All models, including the dual turbo engines, provide an excellent blend of performance, efficiency, and dependability. The M276 does not have many common faults or design flaws. Unlike several other manufacturers, Mercedes was also able to avoid any widespread DI difficulties.
However, as previously stated, twin turbo engines incur additional maintenance and operational expenditures. The M276 DE30 and DE35LA engines are still fantastic all-around. Regardless, boost causes some wear and tear on components such as spark plugs, ignition coils, and so on. There are other parts that could fail, but there don’t appear to be any typical turbo-related issues with the M276.
Some dependability is simply a matter of luck. We do, however, have some control over maintenance. Use high-quality oils, change fluids on schedule, and address concerns as they arise. Maintain the Mercedes-Benz M276 engine properly, and it will most likely reward you with a pleasurable and dependable driving experience.
Summary of Mercedes M276 Common Issues
The M276 engine family from Mercedes-Benz has a lot to offer. A 3.5L normally aspirated V6, a 3.0L twin turbo V6, and a 3.5L twin turbo V6 are all available. They’re all terrific engines with a decent mix of performance, dependability, and efficiency. However, no engine is flawless, and the M276 is no exception.
Direct injection is a fantastic technology, but it does have certain drawbacks. HPFP failures appear to be growing more regular as the M276 ages, however faults are still uncommon. Carbon buildup is generally a non-issue right now, but walnut blasting is probably recommended maintenance around the 100,000-mile mark. Some early M276 engines had a fault that caused rattling on startup due to a shortage of lubricant on the timing chain tensioners.
Otherwise, we discussed spark plugs and ignition coils to emphasise that turbo engines can be more difficult to maintain. However, the Mercedes M276 twin turbo engines are proving to be quite dependable. Maintain the M276 properly, and it will most likely be a good, dependable engine that you will enjoy for many years.
