I have a 2008 Audi RS4 with a slow oil leak from the oil drain plug. I have added about 1 qt/1000 miles lately to give you an idea of how much is leaking. I have been told by a repair shop that the leak is because the oil drain plug / crush washer and the oil pan have some kind of warping and the crush washer will not seal like it should anymore. They are recommending replacing the (lower) oil pan. (The RS4 has an upper and lower oil pan. According to the shop, only the lower needs to be replaced.)
Does the explanation that was given to me make sense? Is this really how the oil pan seals? Do I really need to replace the lower oil pan?
It sounds fishy that the oil pan would warp. The crush washer is intended to "crush" down and fill in any gaps between your oil plug and the oil pan. I'd try simply replacing the crush washer first to see if it stops the leak. Crush washers should be replaced regularly. Some recommend replacing them with every oil change.