Came back from a road trip and puddle on the right side engine bay. Diff Seal Leak?
 

Came back from a weekend roadtrip and today I noticed a pretty sizeable puddle on the right side of the engine bay. Looking closer, it looks like the leak is coming from the diff shaft seal. It looks like the O-ring is dry and I can't tell if there are any leaks above it. I think I only see the exhaust headers?

This car was a recent purchase in April, and I had the dealer replace the front + rear diff fluid before delivering to me. Could all this fluid have suddenly leaked out of the shaft seal?

My only concern is that I thought diff fluid smelled terrible, but this didn't smell too bad. The liquid was slick and gold-ish.

Does anyone have any experience with this? I'm pretty sure it's that shaft seal but wanted to check with everyone here. I'm thinking it's Part #7 in this realoem diagram.

https://www.realoem.com/bmw/enUS/sho...diagId=31_0514

Pics of the leak below.

https://imgur.com/a/ljEdQex

Pic doesn't seem to be loading. Love the no oil change note on realoem too :)

The 3 pics in the imgur link aren't working? That's weird. I'll find a different host.

- You can upload jpegs to this forum. Just click on "Manage Attachments" icon.

- Best is to clean the oil leak, then monitor it daily. Maybe it was overfilled?

Oh nice! I didn't know I could do jpg directly. I clicked on the Insert Image button but it only asks for a URL.

I'm just kind of suprised this leak came out of nowhere. Like a 6 inch diameter puddle of a leak when it was previously leak free. I looked more closely under the car and I'm pretty sure it's the Diff Axle Seal, but wow it went from no leak to pretty bad leak so quickly.

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My first thought is PS if you don't have oil coming out the filter housing. Use a very bright light and shine in under/ around the oil filter housing.

Pretty sure there's no fluid inside the shaft housing to leak out.... so likely to be something above the shaft housing.

The PS and Filter housing are on the left side of the engine bay. I guess this is confusing but I have a left hand drive car, my leak is happening near the passenger front wheel.


There has to be fluid right? I've seen posts about diff fluid leaking out of the O-ring (Part #8 in the diagram). If that O-ring is sealing fluid, than the part #7 must be sealing something too.

I'm thinking leak from a PS hose under. Also leak from the OFHG can come down the front and leak out anywhere. (due to stiffening plate).

Look in under the oil filter cap and makes sure no oil there.

You can check fluid level in the dif if concerned it's leaking from there but dif won't likely make a puddle they aren't filled above the output shafts you get dribbles usually.

Looking from the top of the engine bay, it looks like the stiffening plate isn't wet, just the output shaft. It looks like the output shaft if dripping onto the edge of the stiffening plate where it meets that black tubular framing.

I'll take a closer look later today at the OFHG and report back on that though!

If it was PS the fluid would be more of a red-tint though right? I checked my PS reservoir and the fluid level seems fine.