E350Cdi 2012 - Engine Bay Fluid Leak! ATF or PSF?

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Active Member
Jan 30, 2021
2012 C207 E350Cdi
Last couple of days I noticed a noise coming from engine bay which almost sounded like the ancillary belt. I took a look when I got home today and noticed some fluid around the bottom of the bay below the radiator and some on the ancillary belt.

At first I thought it was engine oil but once I jacked the car up and took the undertray off I noticed it wasn't black like engine oil. But it was all over the place so looks like it released with some force.

It must be either power steering fluid or transmission fluid.

Do these models have a transmission fluid radiator at the front with pipes carrying the fluid? Or is this most likely power steering fluid? The PSF level reading looks about normal, and doesn't seem low enough to have resulted in the amount of fluid leaked.

There is also a pretty significant noise from what I thought was one of the pump pullies on the NS, but when I was spraying brake cleaner some hit the belt and it temporarily stopped the noise, so almost belt related.

Lastly I also noticed whilst trying to find the source that with the engine running there is a belt tensioner / dampener? which vibrates and moves a lot during running. Is this normal? (I will try and research technical name of this piece and update but it sites behind the turbo boost resonator).

Rough video:

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Just watched the video on my phone, can’t really see a leak clearly
Is it the same fluid splashed all over the underside of the resonator box circa 50secs?

I note the turbo hose and connection near by? Worth a wipe, wiggle and maybe removing the hose to look for leaks or damage (i.e. could it be oil in the turbo pipework being blown out of the pipe and everywhere, or dripping from pipe seals and on to belts). Difficult to seen in the vid and work out which way exactly is up and down.
Check the hose that is passing over the crossmember near the central jacking point. I think that is the hp power steering line. Where it rubs on the crossmember it can wear and leak power steering fluid. You will only see it leak when someone is moving the steering for you. My 2010 A207 hose failed like that.
Have a close look at the intercooler hoses.
They have a tendency to split and this could explain the "all over the place" and also the noise reported in the OP's post.
Splits are hard to spot.
It's a question of looking for a black split in a black hose in the dark.
I had one recently on the E280cdi.
It was a big split but it was not easy to spot.
If you touch the substance with a tissue and it smells like diesel, it likely contains diesel fuel.
No way !!!!

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