One of the more challenging tasks in this business is identifying the correct service fluid for a vehicle system. Some fluids, such as engine oil, are easier than others, such as for a transfer case. But if you know how to approach the problem, the answer is actually easy to find.

To identify any service fluid, the primary information source is the Mercedes-Benz Workshop Information System (WIS) where the so-called Specification Sheet for a service fluid will be given. From there, you can identify the approved fluids in the BeVo online database. From there, you should have no trouble getting what you need.

The first step is to determine what it is you are looking for. Sounds simple (and it is) but skip this step and you risk “going down a rabbit hole” and wasting time looking. Positively identify the vehicle component you need information for. This might be the transfer case, the transmission, the power steering system, or the rear axle differential. Once you know what part it is, find it in WIS.

Find a job in WIS that has something to do with the component. A good choice is to look for a repair instruction (AR document) that both applies to the vehicle and is likely to require a fluid change or addition. For some components, you’ll find a job with a name like “Drain and refill fluid” or “Oil and filter change” or “Capacities,” while for other components “Remove and reinstall <part name>” is usually a reasonable choice.

Within the repair instruction document, find the step where the service fluid is checked or filled: On that instruction line, you might see a reference to a “Sheet No.” for the service fluid, or more likely there will be a blue or red Hyperlink to additional information. In some cases the part number for the needed product is shown at the bottom of the document, so be sure to check.

Blue links lead to another part of the same document. Red links lead to a different document. Pay careful attention to the actual link number, particularly for the blue links. Nearby “Image 1” shows an example of the information you will find, in this case a (blue) link to the filling capacity specification *BF35.31-P-1001-01E.

Following the link you will generally find both the fluid capacity and a red link to the specification sheet (BB document), as seen in “Image 2.” Note that the actual blue link number is shown at left. Since we have a Model 210.065, the right-most column is what is correct for this vehicle: A filling capacity of 1.1 liters, and a Red link to document BB00.40-P-0235-07A.

Clicking the red link brings up the specification sheet 235.7, seen in “Image 3”, containing three approved products. On every specification sheet you will always find at least one approved product, and its supplier, for the specific fluid. In most cases there will be several products shown, with those available from Mercedes-Benz shown at the top, with the part number.

Although the WIS document should be up-to-date, the Mercedes-Benz BeVo website https://bevo.mercedes-benz.com/index.php?language_id=1 also contains all the Specification Sheets, and should be considered more up-to-date than the Specification Sheets in WIS. In “Image 4” we see that the BeVo site also has two Mercedes-Benz part numbers listed, which you can order from your dealer. Missing is the package size, two additional digits after the part number, but your dealer can look up what’s available for you in the parts catalog’s Parts and Operating Fluids section.

Take a look at the other products: Since all of these are approved, if you can find that product locally it is a perfectly acceptable solution to your problem: If you can buy the exact product, it is OK to use in the vehicle. The key word here is exact: Mobilube 75W85 is not the same as “Mobilube FE 75W85.”

There’s nothing worse than using the wrong service fluid, since your customer will surely return with bigger problems than before, and you might be liable for the repair if you used the wrong stuff. But WIS tells you the specification sheet, and the sheet in WIS or BeVo tells you which approved products you may use. If you always use a Mercedes-Benz approved product, you know it’s the right stuff.