Audi A4 B8.5 (2013) Oil Leak from Passenger Side Front Rear Control Arm?
 

Hi There,

I recently noticed oil drops on my level driveway.

On initial inspection; noticed the oil was dripping from the Front Lower Rear Control Arm bushing. I am still not sure whether these are oil filled or not. Anyhow, I have now taken the car to two different garages and both were not able to find any evidence of oil coming from anywhere else. The top of the bushing is quite dirty but does not have any oil evident. Seems to be coming from the bushing itself. The person at the workshop had a closer look into the bushing; the plastic piece on the bushing had cracks on it, but when we tried poking a small screw driver in the area; it didn't leak any oil - Not sure how these are constructed. The driver side also had cracks but there was no evidence of oil on that side.

The oil is dark; and does not smell.

The oil only leaks when the car is driven; Last week I didn't drive the car at all for 5 days; there was no evidence of oil on the driveway or on the lower side of the bushing at all.

Is it correct to assume that the Control Arm bushing is leaking? Do they have oil in them?

Either garage said that nothing else above is leaking as there is no evidence of it; some of the bushings are oil filled. Although they inspected the bushing themselves and there was no movement in them what so ever. It seems to be a bit of an inconvenience with the oil leaking on the driveway. Either garage did ask me if my driveway was at an angle, but because it is levelled it doesn't seem like oil is flowing from somewhere else as well, but again no evidence of oil above the bushing.

Is it worth changing the control arms? Also is it worth changing both Driver and Passenger side at the same time or just change one.

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The bushings in the curved lowers are hydraulic if they are the 75mm versions. This was changed over the course of the B8.0 years. All B8.5 should have 75mm hydraulic.

Is the oil a supporting component, or just a dampening component? They were used in place of the 65mm conventional due to owner complaints of vibrations. But for your case, the question means can you continue to operate as is or should they be replaced asap.

The bushing itself can be replaced. There's no statement in the repair manual about needing to replace those arms in pairs. It might be cheaper to buy an arm, it might be cheaper to buy a bushing and have it replaced. You'll have to evaluate your price options.

Thank you for your response on this.

Just an update; the oil has stopped leaking now - Not sure why. Couple of workshops have in the current status assumed that it may will be grease that when mixed with water is leaking as oil shape. As it has stopped raining for a few days, I am not seeing any leakage evident.

I would be keen on getting the control arm changed.

Is there a directory where I can acquire the appropriate part number for Arm/bushing?

Would be 8K0 407 693 AD left side or 8K0 407 694 AD right side for the arm with bushing. revision AD replaced rev AA which had replaced rev Q.
Would be 8K0 407 183 G for just the bushing. revision G replaced rev F which had replaced rev D.