Hello, folks. I have been working on getting my 2009 GL320 up to snuff for the past few months. It now has 144,000 miles on it.

It is dropping about a quarter size spot on the floor every other day. When I look at the engine, I see two of three likely areas that are wet and become wet again after being wiped clean.

First, there is an area in the front of the engine where a large hose is attached to the front of the engine, down low, near the crank with a clearly damaged end and worm gear clamp. I see it as black and I believe it drips down onto the oil pan.


You can see the damaged hose end, worm gear clamp and wet spot on the oil pan metal here. I don't think this is the source of my leak that gets to the floor, though. What is the name / part number of this hose? How urgently would you treat this issue? It doesn't seem like a high pressure hose.

Next, if you move up on the front of the engine, you get to the area where there is what I believe is the diesel injector / pump area.

There is a seam connecting metal to plastic near the green dot that will become slightly wet. It doesn't drip oil, but just gets greasy / misty looking. The area around the green dot on the black plastic tube also appears covered in an oily residue. What is this part of the engine called? I suspect there may be a leak at this gasket or a crack in the pipe leading to oily mist getting all over.

While this part of the engine is leaking something, I don't believe it's getting to the floor either. It's not enough oil flow, having wiped it down from time to time, and it's not the right spot on the ground.

So then we move to the back and top of the engine. There is the large metal tube leading to the turbo. There is a black seal of some kind that connects to the tube to the turbo. There is oil coming from that joint. If I look down from that, it falls down on to some wires below the "batwing". I suspect it continues to drip down from here onto the floor, but I don't really know.

You can see the joint I'm talking about to the rear of the batwing on the right side. It is the black seal just to the front of where the M53 is cast. There's not much oil to see in this picture because I already wiped it. Not enough wet oil to soak a shop towel but enough to easily make a mark. Perhaps this o-ring or seal should be replaced.

Note that I have already replaced the CCV inlet seal and the main batwing - turbo seal and that may have helped but it didn't eliminate the problem.

Based on the depth of the leak relative to the front of the car, this is the best candidate for the source of the oil on the ground. It doesn't seem like enough oil to make a spot every day, though.

I've read about the oil cooler seal leak already, but what I read suggested that if that was the leak, it would be leaving a lot more oil on the floor. This leak has been small and steady for the past couple months and several thousand miles.

As the car is about to go in for its AEM service in early 2022 and get back under warranty for certain parts of the engine, I'd like to know what is possibly covered by the new extended warranty such as turbo related or EGR related.

Based on the age / miles of the car, it doesn't necessarily make financial sense to pour a ton of money into these leaks, but I would like to fix anything that might solve the problem. I wouldn't be above some Southern engineering with some epoxy or other non-sanctioned fix. I was also thinking I could rig up some sort of undercarriage absorbency or catchment to protect the floor.

Any suggestions would be appreciated. Thank you!