The Mercedes M113 V8 Engine Issues – Reliability and Specifications. The Mercedes M113 engine family first appeared in 1997. It comes with 4.3, 5.0, 5.4, and 5.4L supercharged engines. Power ranges from 275 to 574 horsepower, which are outstanding figures for the time. Some believe the M113 to be one of the brand’s best engines. However, no engine is perfect, and this is no exception. This page discusses Mercedes M113 engine issues and reliability. We also go over the M113 V8 engines’ performance, specs, and general information.
Variations on the M113 Engine
Again, depending on the model, the M113 is available with a variety of engine sizes. All of these V8 engines are based on the same basic architecture. We’ll go over M113 engine specs in the next part, but for now, let’s get started.
M113 4.3L Engine
This is the smallest of the M113 engines. It has a bore and stroke of 89.9mm x 84mm and a displacement of 4.3 liters. The engine produces 275 horsepower and 295 pound-feet of torque. C43 AMG vehicles get a little more power, with 302hp and 302 torque. Mercedes M113 4.3L engines can be found in the following vehicles:
- 1998-2000 C43 AMG
- 1998-2002 E430
- 1998-2003 CLK430
- 1999-2001 ML430
- 1999-2006 S430
M113 5.0 Engine Mercedes
M113 5.0L models have a 97mm bore and 84mm stroke. It has the same stroke as the smaller 4.3L engine, therefore only the bore has been expanded to accommodate its bigger capacity.
The power and torque figures are 302hp and 339lb-ft. It is available in the following Mercedes-Benz models:
- 1998-2008 G500
- 1999-2006 S500
- 1999-2006 SL500
- 2000-2006 CL500
- 2001-2006 ML500
- 2002-2006 CLK500
- 2003-2006 E500
- 2004-2006 CLS500
- 2006-2007 R500
5.4L NA M113
The M113 engine’s 5.4 variation is the largest. It has the same 97mm bore as the smaller 5.0, but the stroke is longer at 92mm. This engine produces 342-362hp and 376-391 lb-ft of torque. Very excellent figures for a normally aspirated engine from the late 1990s. In the SLK 55 AMG Black Series, the M113 is likewise tweaked to produce 396 horsepower. The following 55 AMG vehicles are powered with 5.4L M113 engines:
- 1998-2000 C55 AMG
- 1998-2001 SL55 AMG
- 1998-2002 E55 AMG
- 2000-2002 S55 AMG
- 2000-2003 ML55 AMG
- 2000-2006 CLK55 AMG
- 2001-2002 CL55 AMG
- 2002-2003 G55 AMG
- 2004-2010 Mercedes-Benz SLK55 AMG
- SLK55 AMG Black Series 2006-2008
- 2005-2007 C55 AMG
*Many supercharger kits are available that provide comparable performance and results to the M113K that we’ll be addressing next.
M113K supercharged 5.4
Last but not least is the Mercedes M113K engine, also known as the M113 5.4 Kompressor. The displacement is the same as the previous NA 5.4L engine. This engine is taken to the next level by a supercharger and dual intercoolers. The output ranges from 469 to 574 horsepower and 516 to 590 pound-feet of torque. Mercedes-Benz cars that use the M113K supercharged engine include:
- 2003-2006 CL55 AMG
- 2002-2006 S55 AMG
- 2002-2008 SL55 AMG
- 2003-2006 E55 AMG
- CLK DTM AMG 2004, 2005, and 2006.
- 2004-2011 G55 AMG
- CLS55 AMG 2004, 2005, and 2006.
Mercedes M113 Engine Specifications
The fundamental distinction between the engines is their size, bore x stroke ratio, and compression ratio. The M113K supercharged model, on the other hand, has some noteworthy differences. We’ll return to this subject in a bit. The 4.3L, 5.0L, and 5.4L engines, on the other hand, share the same basic design and architecture. They have three valves per cylinder and an aluminium block and head.
Forged connecting rods, cast camshafts, and a magnesium intake manifold are also standard on all engines. Some people admire the M113 engine’s simplicity. It was created before VVT was popular technology. Despite their simplicity, Mercedes M113 engines produce impressive power and torque for their age.
We previously noted that supercharger kits for the basic 5.4L V8 Mercedes engine are available. The M113K, on the other hand, has numerous improvements over the NA 5.4 engine. Most improvements are designed to help sustain the supercharger’s increased power and boost. The 5.4 Kompressor engine now has a stronger crankcase, crankshaft, pistons, and other components.
Mercedes also performed minor head modifications to improve engine flow and raise redline. The point is that slapping a supercharger on the 5.4L M113 does not automatically make it the same as the actual M113K engine.
3 Common M113 Engine Issues
Among the most prevalent problems with Mercedes M113 engines are:
- Main rear seal
- Pump for intercooling
- Plugs for sparking
We’ll go through the above M113 issues in further detail over the rest of this essay. However, before moving on, it’s a good idea to make some notes. These are among the most common issues, in our opinion. That doesn’t always imply that they’re common in the proper sense of the term. Rather, these are a handful of the common areas where difficulties or failures arise.
Having said that, many people believe the M113 engines to be relatively basic and reliable. However, age is a significant role. Many of these Mercedes M113 engines are over two decades old. That kind of age can raise questions about dependability and lifespan. We discuss overall M113 reliability and expand on this information at the end of this essay. For the time being, let’s focus on the problems with the M113 V8 engines.
1) Leaks in the Mercedes M113’s Rear Main Seal
The first issue is connected to the age and mileage of most 4.3, 5.0, and 5.4L Mercedes V8 engines. Many cars and engines have oil leaks as they age. Rubber-like seals and gaskets deteriorate and fracture over time. That is precisely what occurs with the M113 rear main seal.
A rear main seal is in charge of sealing the crankshaft at the point where it links to the gearbox. When cracks form, oil begins to seep. It usually begins as a minor leak that worsens with time. As a result, M113 rear main seal leaks are rarely an emergency. However, you should still replace the rear main seal before the oil leak becomes too severe.
Because of labour costs, it is an expensive problem. Main seal leaks are also becoming increasingly common as these Mercedes M113 V8 engines age. whether you’re looking for one of these vehicles, see whether it’s been replaced. Otherwise, it could be a problem in the near future. Other oil leaks, such as valve cover gaskets, are also frequent as these engines age.
4.3, 5.0, and 5.4L Rear Main Seal Issues
The following are symptoms of an oil leak from the M113 rear main seal:
- There is a visible oil leak.
- Loss of oil
The most likely symptom is visible leakage on the ground towards the rear of the engine bay. It is frequently the only symptom you may notice. If the leak is severe enough, you may notice that the Mercedes V8 is using more oil than usual. However, with a leak that bad, you should have seen it long ago.
Other leaks, such as valve cover gaskets, may create symptoms such as mild smoke and burnt oil odours. A rear main seal rarely causes problems since the oil flows to the ground rather than onto hot components.
Replacement of the Mercedes M113 V8 Rear Main Seal
A leaking rear main seal necessitates gearbox replacement. Labour is typically somewhere in the 7-10 hour range, therefore labour alone can easily add up to $700-1000+. Fortunately, the part is under $20. It’s a difficult job that necessitates the use of specialised equipment. Only experienced DIYers should attempt to replace the rear main seal on the M113 or M113K.
2) Issues with the M113 5.4 Kompressor Intercooler Pump
The supercharged 5.4L Mercedes M113K features intercoolers. As a result, this is a problem that exclusively affects high-performance engines. The charge air (pressurised air) is cooled by the intercooler system. Without it, the intake air temperatures (IATs) skyrocket, causing the computer to shut down the supercharger.
Anyway, the problem is a breakdown of the M113 intercooler pump. If the original IC pump fails, an upgraded Bosch 010 pump is a viable replacement. For those running more boost and power, aftermarket options are also an excellent idea.
When the entire intercooler system is just inefficient at higher boost, an IC pump is sometimes incorrectly replaced. Increasing boost generates more heat, which can quickly overwhelm the stock intercoolers. It’s something to think about if you’re modifying or altering the Mercedes 5.4 Kompressor.
Symptoms of a Mercedes 5.4L IC Pump
Among the signs of intercooler pump failure on the Mercedes M113K engine are:
- Power outage
- The supercharger has been turned off.
- IATs that are high
When the pump fails, the intercooler system operates at a reduced capacity or shuts down completely. This causes IATs to rise, resulting in poor performance. As temperatures rise, the computer will reduce boost and timing to avoid knocks. When the IATs become too hot, the computer will shut down the supercharger completely.
Again, these are indicators of an intercooler system that is simply overloaded. If you’re doing mods, you should think about getting an intercooler and other cooling upgrades.
Replacement IC Pump for M113 V8
The revised Bosch 010 part can be found here. If your original M113 Kompressor intercooler pump is failing, this is a good replacement at just over $150. This pump has a little higher flow rate and appears to be more reliable than the earlier pumps. Labour at a repair business is likely to be a couple of hours, so budget for some more money there. It is not a difficult DIY for individuals who are familiar with engines. Here’s a simple video on replacing the M113 IC pump.
3) Spark Plugs for Mercedes M113 V8
We’ll go quickly through this area because we don’t consider spark plugs to be a major issue. Most engines, including the Mercedes M113, require spark plug replacement as part of routine maintenance. However, it’s worth the mention since the V8 engine uses 2 spark plugs per cylinder. That’s right – this engine uses a whopping 16 spark plugs.
In some respects, this underlines certain critical aspects of having high-performance engines. Even when they are dependable, they might be more expensive to acquire and operate. Anyways, spark plugs are a natural wear and tear item but they’re essential to proper operation.
16 spark plugs leaves a lot of room for potential issues. Premature failures aren’t common, but it does happen. Additionally, the supercharged M113K will burn through spark plugs fairly quickly. Boost leads to higher cylinder pressures and puts more stress on ignition components. Don’t overlook something as simple as spark plugs.
MBZ M113 Spark Plugs Symptoms
The following symptoms may point to old, faulty spark plugs on the Mercedes-Benz V8 engine:
- Power outage
- Rough idle
- Stuttering / hesitation
As spark plugs wear down they can no longer fully ignite the air/fuel mix in the cylinder. This generally leads to misfires which may show a plethora of other drivability problems on the M113. Power loss is a possible symptom, but it’s often hard to notice on a V8 engine unless multiple cylinders are misfiring. Rough idle and stuttering while accelerating are also common symptoms.
Spark Plug Replacement
A set of all 16 spark plugs for the M113 engine typically runs around $90-125. Overall, that’s not too pricey but it is double the cost of spark plug replacement on a lot of other cars. The spark plugs should be changed roughly every 50,000 to 80,000 miles. However, the Mercedes M113 5.4 Kompressor will likely burn through plugs a bit quicker. Replacing spark plugs is a very straight-forward job that most can knock out in the driveway or garage without issue.
Mercedes M113 V8 Reliability
Is the Mercedes M113 V8 a reliable engine? Yes, we believe this engine earns average to above average regards for reliability. The M113’s relative simplicity compared to newer engines helps with reliability some. However, it does have age working against it.
As engines age they naturally require more TLC. Oil leaks, especially the rear main seal, are becoming more common on the Mercedes-Benz V8 engines. The supercharged 5.4 M113K is also a bit more demanding on maintenance. Intercooler pumps are one weak spot on the engine, too.
Regardless, the M113 is still a solid and reliable engine all around. Given the age it’s important to look for an example that’s been well maintained. A lot of issues that M113 owners run into are self inflicted. Use quality oils, change fluids on time, and fix problems when they occur. Do all of this and the M113 V8 can live a long, reliable life.
M113 V8 Engine Problems Summary
Mercedes first released the M113 engines in 1998 models. They’re available in four different variants: 4.3L, 5.0L, 5.4L NA, and a supercharged 5.4L engine. All engines share the same base design and are capable performers for their era. The 5.4 Kompressor is the most capable, but as a higher performance engine it can be more demanding to own.
Anyways, all variants of the M113 engine offer solid reliability. Oil leaks are becoming commonplace as these engines continue aging. The Mercedes M113 Kompressor is known to have issues with the intercooler pumps. Otherwise, we discussed spark plugs to highlight the fact performance engines can be a bit more demanding on basic maintenance.
Most importantly, look for an example that’s in clean condition with good maintenance. Even though these engines are getting old they can still be pretty reliable when they’ve been taken care of well.