[BMW FOREVER]

Hi guys…few months ago I had noticed a few wet patched on the underbody protection of the car..thinking its normal I didn't really give it a second thought and today I noticed this (Pictures below) any idea what is yellow looking liquid could be?

[Noggie]

Front or rear of car, right or left?
Sedan or wagon?
Think we need a bit more information.

Is that the rear wheel well, and a jack pad in the pictire?

There are not many fluids that color in the car.
My initial thought was break fluid, but of you have had this for a month, I doubt it.
Could be a shock leaking, but you would have noticed that.
The wagon has rear air suspension, and this has a compressor that is lubricated, so it could be the compressor lubricant.

Anyway, a more specific explanation where this is on the car will help.

If this is the front wheel, based on the colour and spray pattern, I would guess perhaps a brake hose leaks when you are applying brakes and turning as this stretches the hose. The leak could be in a connection when force is applied is a specific direction.

But on a general note.
Engine oil is golden to black depending on age.
Anti freeze (radiator) is usually blue on BMW, but can be red.
Gearbox oil is red
Diff oil is red or golden.
Brake fluid is clear or yellowish-gold.
Hydraulic oil is red or gold.

[BMW FOREVER]

The leak is on the front left of the car…the wheel well you see is the front left…I got the break fluid replaced a month ago…so maybe it's that. Not sure…but the car comes with standard suspension and its an F10.

[Noggie]

Originally Posted by BMW FOREVER

The leak is on the front left of the car…the wheel well you see is the front left…I got the break fluid replaced a month ago…so maybe it's that. Not sure…but the car comes with standard suspension and its an F10.

Check the caliper bleed nipple, could be that it is not fully tightened after they bled the brakes.
You can also check your brake fluid level and check if it has dropped, a low level should give you a warning light, so it har probably not dropped much yet.

[mko9]

Based upon the spray pattern in the wheel well, I would go with brake fluid. The next most likely would be a blown shock.

As said above, make sure the bleed nipple on the caliper is closed. Don't crank on it too hard, you don't want to snap it off. Then check your fluid level in the reservoir in engine bay. It probably needs fluid. If it is below minimum, or empty, you should probably bleed the brakes.