Recommended Mercedes Oil
At FMW we use only full synthetic motor oil with specification 229.5 on newer gasoline engines produced after 1998 with FSS, these motors are M112, M113, M272, and M273. On these engines we don’t use paper filters, as fleece oil filters are preferred with synthetic oils. Newer diesel engines have a different oil specification (229.51). It’s critical to observe the correct oil specifications for each motor, both of type and viscosity range, because sludgeing, advanced wear, oil consumption and corrosion have been known to result from not doing so. Older engines without FSS can in most cases be converted to full synthetic oil without problems and synthetic oils are preferred. This will extend the service interval in most cases. Because the oil filter on a pre-FSS engine with cast iron cylinder walls was designed with a service interval of approximately 5000 miles it would be detrimental to double the service interval without changing the filter halfway to 10,000 miles. Given this extending services to 7500 miles or scheduling just a filter change every 5000 miles would be a safe route around this.
It is important to note that using conventional oils of the suggested viscosity range and changing at the recommended interval is always the best safest route to vehicle maintenance. Because it is common for recommended service intervals to be exceeded, motors to be subject to severe conditions, short trips, and long periods of sitting, the greater protection of synthetic oil should be a consideration. Because the benefits of synthetic type IV oil can only be achieved if it is not mixed with conventional type II and III oils, we recommended not extending a service interval until after the second synthetic oil and filter change. This is not based on a study, but on the realization that on most Mercedes engines all the oil cannot be made to drain during an oil change. Some of the remains are captured in recesses and cling in passages that don’t drain completely and will therefore mix with the added synthetic oil during the first change. The amount mixed in this case is small probably less than a pint, so one change should be sufficient to scavenge it from the engine.
Fleece oil filters were designed for extended service intervals with full synthetic oils. They are more rigid, don’t loosen up with time, and have a smaller pore size with higher surface area to hold more material that would otherwise be in suspension in the engine oil. On most models Mercedes uses a replaceable oil filter cartridge and not the common spin on type filter, as a result the cartridge must fit into the filter housing correctly. Inexpensive poor quality paper filters often fall out of the filter housing during an oil change when they should still fit tightly enough to only be twisted off. If an oil filter doesn’t fit tightly the oil can flow around the cartridge and not through it. If it doesn’t have high surface area it can get clogged and the oil will bypass the filter when the pressure becomes high enough. If it has a large pore size or tears more solids will continue to circulate in the engine and increase wear. Mercedes-Benz engines can easily last several hundred thousand miles with very little wear; provided the maintenance is done on schedule and with approved parts and specified fluids if it is approved (non-FSS engines only). Often many premature engine failures can be traced to poor maintenance at one point in the engine life.
The problem with hunting for the lowest price on an oil change it that in many cases, you will find a shop not using an oil meeting the correct specification or using poor quality filters and not performing the work correctly. Many of the motors have no dipstick and overfilling or under filling are common problems, both of which can cause engine damage. This occurs because not all motors in a series have the same oil capacity. Dealers evacuate the fluid from the dipstick tube rather than draining it in all but a few engines. Draining it is fine if you are patient, but the encapsulation panels and screws under the car can be damaged when they are removed and reinstalled quickly. Oil drain plug seals will leak when not replaced each time. We evacuate the oil from the dipstick tube with a vacuum tube that can be placed on the bottom of the oil pan as does the dealer, if done correctly while hot this will remove more oil than can be drained due to the placement of the oil drain.
One overlooked maintenance items are the oil filter housing o-rings with as many as 4 depending on the engine model. When performing a service we always replace these which avoids poor o-ring sealing, possible oil bypassing the filter, and more commonly external seeps and leaks when they are not replaced each time. This may seem obvious, but it is common to see the effects of this step having been omitted, resulting in a seeping oil filter housing. An o-ring will set on first installation and as it ages and becomes more brittle it will develop a flat face. If it is removed in this condition it must be replaced or it will leak or minimally seep when reinstalled. The o-rings are included in an OEM filter kit and there is no additional parts cost other than the labor to replace them which is included in the oil change.
Although prior to model year 2005, motor oils satisfying 229.3 or 229.5 specifications can be used, we use only 229.5 on all FSS engines. It is important to make clear that not all synthetic motor oils satisfy the 229.5 oil specification. We currently use Total Quartz Energy 9000 5W-40 as do many MB dealers in gasoline engines requiring synthetic oil. Advertizing costs and marketing efforts of producers as well as supply and demand govern oil prices. We make every effort to buy the most competitively priced oil that is available in out of area, provided MB approved to meet its specifications, in order to keep the cost of services as low as possible. FSS diesel engines typically use full synthetic Mobil 5W-40 ESP satisfying 229.51 which has a slightly different additive package and viscosity range.
Full synthetic oils have more stable shear strength with heating and even with more frequent oil changes non-synthetic oils cannot match that performance under load at high temperature. Some have argued that if you add up the cost of more frequent conventional oil changes on older vehicles, that were shipped with conventional oil, then compare them to the longer synthetic oil service interval with fewer changes the synthetic oil is then competitive in price. As we mentioned before the oil filter should in most cases not be subjected to the extended service interval because it was not designed for it, and the synthetic oil route will be more expensive. This is an inexpensive insurance considering the high cost of a motor rebuild or swap.
Specifications from WIS are converted from liters. These quantities are for an oil and filter change only. Please consult your owner’s manual to confirm they are correct for your application. When changing the filter make sure you change all the o-rings and use a good quality filter. On the M112, M113 and M272 and M273 motors use a fleece filter.
112, 112.975 8.5qts
112.916, 112.953 7.9qts
156 in W164 10.3qts
156 in W204 9.0qts
156 in W209, W211, W219 9.3qts
156 in W221 10.0qts
156 in W230 8.5qts
156 in W251 10.15qts
M273 9.0qts note GL is about 10.0-10.5qts
602.91 w/ EGR 7.4qts
602.96 603.91 except 603.913 7.4qts