All,

Got under the car for the first time in 1500 miles (last time was to change oil & filter) and was very unhappy to find the pictured leak of unknown kind and nature (whatever the fluid is, it's fouled by dirt and grime). It's at the lowest-to-ground point where the starter and engine block mate. Before anyone asks, the rectangular-ish hole is normal, I found videos of not-my-car that show the same hole.

1500 miles ago this area was bone dry, and this is the first time I've seen a leak in this location in my ownership of the car. Have been under there plenty of times before so firmly convinced this is new. Everything else is dry, and this does not appear to be coming from higher up in the engine. What you see is pretty much what you get.

Questions are:

(1) What is this? Engine oil (my guess) ATF? Other?
(2) What part is leaking?
(3) How bad news is this bad news? (depends on item 2, I imagine)

Underbody tray is fairly dry but does show small (like drop-sized small) spots where whatever this is has landed and then combined with dirt to become gunk. More dirt than fluid, in fact, some spots have 1mm-3mm vertical height on them. But there aren't a lot of these spots so this hasn't been going on long.

Very much appreciate any fast input. 2017 F56 Cooper S, B46 engine, US spec, stock, about 108.5K miles. About to do a big road trip so def need to know what this is.

 

Update - I think this is an oil pan leak.

Big circled area at top -- lip of oil pan above the starter. Arrows -- mating seam of starter and engine block. Small circled area - top bolt holding starter to engine block.

There's a lot of "unexplained gunky dirt" on the top side of that oil pan lip, interesting because otherwise the area is really clean. You can see some of the dirt (more came off on my fingers). This is the leftmost part of the rear (as in vehicle rear) of the oil pan. Head further to the right and things are clean, but there is (1) less of a lip and (2) interestingly, RTV or some kind of sealant vs just signs of a gasket. Not a *lot* of sealant, but no question that it is a sealant. We know how sealant applications can turn out, sooo... anyway.

That lip runs to the mating seam noted. Any fluids hitting that seam would likely wick down, showing up at lowest-to-ground point (which is the bottom starter attachment bolt).

That clean-looking upper starter bolt circled wasn't so clean when I got to it -- also had "unexplained gunky dirt" until I cleaned it up.

So prelim diag -- oil pan leak at top, wicking down seam to starter botls along seam.

Have cleaned this up and going to stop freaking out about this possibly being a weird rear main seal thing, but would love feedback.

 

https://www.northamericanmotoring.co...periences.html

 

Funny, I was thinking I should put it in that thread. After I have a little more of a bead on it, will do.

 

Mine was a 2017 mini cooper s F55 5-door
while lift up the car and remove the guard cover, I discover the same issue just like your photo, also a patch of stain on the cover.
There are no active dripping and also don't know where does it come from, the tech guy told me that may come from the gasket leak in-between the engine and the gearbox
May I ask did you source out where did that come from? it worry me that it may become more serious and cause bigger issue at a later stage.

Thankyou so much

 

I've been watching it for a while now and like you, I am concerned about it. But I still haven't nailed it down. I did speak with a shop that best-guessed -- like I did -- that it was either a leak of the oil pan seal towards the rear of the engine or, worst case, rear main seal.

 

Hey @SunnyK , have an update: see post #51 in the F55/F56 thread "F56 (B48) High Mileage Lessons and Experiences." Short version: the pan itself may be leaking (not the gasket, the actual aluminum pan -- go figure). Just go read the post. Wild.

 

Yep we have seen some pans have issues.

Now we have these: https://www.ecstuning.com/b-bremmen-...1138590017~br/ and https://www.ecstuning.com/b-bremmen-...138611689~brp/

 

You guys have heard about this? Oy! Good to know.

What is the difference between these two Bremmen listings/parts (other than price of course)?

 

The are cast of the oem molds. I have seen them bremmen ones in person and the castings look good, much better then OEM. I think the Genuine ones have a bad cast job based on comparison of other years and models. Like it looks for crack in the cast cracks.

 

Gotcha — and it looks like the diff between your two listings is for the Bx6/Bx8 vs Bx6C/Bx8C? Am I sorting that correctly?

 

Yep just the two engine types.