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Mercedes-Benz E-Class and E-Class AMG: Why is My Car Leaking Oil?

Oil leaks are always an annoyance. Find out how to locate the potential cause in your Mercedes-Benz E-Class.

By Robert Olsson - June 29, 2015
Contributors: Neanicu888, tusabes, amthatiam

This article applies to the Mercedes-Benz E-Class and E-Class AMG (2002-2009).

The Mercedes-Benz E-Class' engine is sealed tight. A leaking oil means one of the seals is not doing its job. If you let the car leak for too long, you could end up driving with low oil, which can eventually ruin your whole engine. When there is a lot of oil outside the engine from a potential leak, it could be very difficult to see exactly where the oil is leaking out from. To find the leak, clean the engine around the area where you found the oil thoroughly. Depending on how much oil is leaking, drive for a little while until you can spot some oil leaking out. There are a couple of places that are easy to locate and sometimes leak oil.

Materials Needed

  • Jack and jack stands to elevate the car

Step 1 – Oil drain plug and oil filter

Make sure that the oil drain plug and the oil filter are tight without over-tightening them. Ideally they should be torqued to the factory specifications mentioned in your owner's manual. Also make sure that the o-ring for the oil filter cap is in the correct groove and not damaged in any way. If the o-ring is damaged, it has to be replaced. If the drain plug or the filter are cross-threaded, the filter cap or the drain plug might need to be replaced.

  • Figure 1. Oil drain plug.
  • Figure 2. Oil filter.

Step 2 – Oil pan

Sometimes the seal to the oil pan under the car starts to leak. When you have your car elevated, take a look around the oil pan to see if there is oil further up on the engine, or if the oil is limited to the oil pan itself. If the leaking oil is limited to the oil pan, then it is probably the oil pan seal that is leaking. If the oil pan seal is leaking, the oil pan has to be removed and a new bead of oil proof liquid sealer has to be applied. Apply the sealer on the edge of the oil pan, then the oil pan is reinstalled on the car.

Figure 3. Oil pan, black and oily in the middle of the picture.

Step 3 – Oil level sensor

The oil level sensor is located on the passenger side of the car in the oil pan. Take a look around the sensor to find any leaking oil. If the sensor is leaking it has to be replaced with a new one.

Figure 4. Oil level sensor at the red arrow and oil drain plug at the green arrow.

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