I've got a 2012 GL350. I've done nothing more to it than perform (I think) service B, or whatever the service was at 20,000 miles, which was oil, DEF, brake fluid, fuel filter. Otherwise, I haven't touched it.

Anyway, there is a bunch of purple fluid dripping on my garage floor, center front of the vehicle. On first glance I thought it was black but it's actually purple in color. I used Mobil 1 when I did the oil change and the previous owner had it maintained at the dealership, so it is factory fluid.

Anybody know what it is or is it time to crawl under there and start looking for the leak? Normally I wouldn't care about that but with all the snow and ice this winter my garage floor isn't exactly inviting. It's under warranty but I want to know what it is before I take it in to the dealer to have them fix it. I've been a BMW guy for 20 years so I don't know all the Benz fluid colors yet.

 

OK, replying to my own post. There is a ton of fluid caught in the pan under the engine. Appears to be a power steering leak. Power steering fluid it low (not registering on the dipstick) and I believe that fluid is brown in color, so maybe what I thought was purple is really brownish. Even as low as it is the steering isn't groaning, which is a surprise.

Anyway, looks like it's going to the dealership for a warranty fix.

 

Will be curious as to what was the origin of the leak. Steering Rack or hose. Hopefully something simple like a low pressure return hose.

 

Steering rack hydraulic line OR oil cooler line.

Hope you have another car planned. The price on the oil cooler "repair" is a joke.

How many miles are on this truck? I bet less than 30,000

 

Is the fluid definitely an "oil" or possibly the MB Q-1030004 dark "blue" antifreeze coolant?

 

OK, so sorry for taking so long to reply - was traveling last week. Wife took the vehicle into the local MB dealer and they call me while I'm freezing my tail off in beautiful Wisconsin. They say that the oil drain plug is leaking - somebody probably didn't replace the crush washer. They tell me they need to do an oil change to replace the washer. I decline it, ask why the power steering fluid isn't registering on the dipstick and they agree it's "a little low." Bottom line, nothing done, no charge. They did do a computer update which took most of day, so I guess it's worthwhile having brought it in. It's under warranty so I'm not going to sweat it - 26,000 miles for those wondering.

Anyway, I finally get the chance to take a look today. I pull the two panels under the engine and they're right as far as I can tell; the insulation covering the panel is soaked in oil. I decide I'm never going to know where the leak is really coming from with that thing on there so I pull it - it's only held on by four small bolts. It's absolutely soaked, so I douse it with brakekleen and sandwich it between two large rags a and squeeze as much oil out as I can. Got a ton out but it's still got a bit in there so I'll just replace it at the next oil change. I'm beating myself up pretty badly, since I've done hundreds of oil changes (race car gets changed after every race and I've been at it 12 seasons...gearbox and diff every third, etc. - I know how to change fluids.) Then I realize that the MB pan is stamped steel and BMW pans (all I've been driving for 20 years) are aluminum. It gets beaten into your head to not over-torque the pan bolt on BMW's because it's so easy to strip the pan and require replacement which is a real pain. Anyway, I *had* replaced the crush washer, I just didn't tighten it enough because I was scared of stripping the oil pan threads on the most expensive car I've ever bought...

So I tightened the bolt another 1/2 turn and I'll check in a few days so see if it's leaking. I'm guessing it won't.

Anyway, while I'm in there I start looking around and I see another leak up higher; looks like intercooler maybe?

Anyway, here's some photos of the leak that I'm trying to identify:

 

No worries on that other leak. Those are from the inter cooler hoses and some seepage is normal. I have a 2012 Sprinter with the same motor as my 2011 GL350 and both seep a little oil.

If you pop off the clip on the hose there will be a little pool of oil in the low part. Just clean it and keep an eye on it.

 

The CAC hose from the turbo to the intercooler can accumulate oil. Ideally it should be a thin film but can buildup if you idle for long periods. The only purplish fluid I am aware of is Royal Purple Motor Oil and MB Blue transmission fluid.