Axle vent leaking oil

[Macho 1]

The air vent on the right axle tube is leaking oil. I ordered a new one and topped off the housing (1/2 qt low).

I took the old one off and looked at it. The cap is loose but still on. Doesn't look like there is much to it, or if it is even broken. Oil isn't leaking from anywhere else.

I am wondering if this is indicative of another problem such as a bad axle seal?

Any rear axle experts here know if there is probably something else going on here than a bad vent?

[JDraper]

The vent is supposed to have a loose cap. That's how they are designed. It's supposed to let air exchange without letting water in.

If your axle is overfilled (you say it was low though) it will come out there, or if you park it on an extreme angle side to side some might leak out. Leaking seals wouldn't do anything to make it come out the vent, they are at the axle ends, and fluid can traverse the tubes.

[YellowMenace]

The only time mine ever leaked was when the guy at the ford dealer used my girdle fill hole like the stock fill hole.


In other words, if you overfill the fluid it will leak out of that vent.

[Macho 1]

The fluid was the same fluid that came with the car. It only started leaking recently. Just wondering why. I haven't changed my driving pattern = fast. I park on a level surface. This makes no sense to me why it would just start up like this. I will see what happens when I get the new vent on. I didn't think there were seals around the pumpkin but couldn't figure out any other reason why this would just start up now, after 4 years and 25k miles.

[Thor]

Originally Posted by Macho 1

The fluid was the same fluid that came with the car. It only started leaking recently. Just wondering why. I haven't changed my driving pattern = fast. I park on a level surface. This makes no sense to me why it would just start up like this. I will see what happens when I get the new vent on. I didn't think there were seals around the pumpkin but couldn't figure out any other reason why this would just start up now, after 4 years and 25k miles.

I feel you may have answered your own question - driving FAST. I have the exact same problem, for the exact same reason...

The conclusion I've drawn is; When we drive the autobahn and sustain high speeds for long periods of time, (theorectically speaking), the differential fluid heats up and expands, that's why there is leakage from the vent.

As a result, I periodically check my differential level just as you've done. Especially after a long trip.

[Macho 1]

But I have always driven fast, for long periods of time, and have never had this problem before. Most of my miles are on the autobahn.

I am going to order a new cover that allows more fluid. Just need time to install the darn thing.

[Thor]

Originally Posted by Macho 1

But I have always driven fast, for long periods of time, and have never had this problem before. Most of my miles are on the autobahn.

I am going to order a new cover that allows more fluid. Just need time to install the darn thing.

Have you checked for leakage every, single time? I hadn't.

I have a high degree of confidence that I've figured out why I have leakage from the vent - but don't know what your problem is...

[Macho 1]

I change my oil on the lift in the Auto Crafts Center. While waiting for the oil to drain I go over the underside of the car and look for leaks, gnawed wiring from the Marders (Weazles) which are bad here, loose bolts and any other thing that looks out of place. I've changed the suspension and the exhaust and this was the first time the axle has ever shown any sign of leaking.
If this is normal then OK but it just seems weird it would start now.
Thanks for the response Thor.

[o3BlueMach1]

man i hate you guys... i wanna live close to the autobahn....

[Thor]

Originally Posted by Macho 1

I change my oil on the lift in the Auto Crafts Center. While waiting for the oil to drain I go over the underside of the car and look for leaks, gnawed wiring from the Marders (Weazles) which are bad here, loose bolts and any other thing that looks out of place. I've changed the suspension and the exhaust and this was the first time the axle has ever shown any sign of leaking.
If this is normal then OK but it just seems weird it would start now.
Thanks for the response Thor.

As I've stated, I suspect heat causing expansion of fluid.

The first few runs I hadn't noticed this either. It DID capture my attention after a hard run for a long duration coming out of Wurzburg with an Audi TT chasing me. I checked the vehicle afterwards and THAT is when I discovered the vent leakage - I don't know what else to tell you.