Oil Cooling Line Leak
 

So when I go to my car after it's been parked, I see oil stains on the ground under the front passenger side. So I jacked it up and saw that the leak was coming from one of two (extremely rusty) metal line that go into the radiator on that side. Upon closer examination I could see that the oil was coming from a small gash in the pipe. The internet tells me that they are called oil cooler lines and they run from the transmission to the radiator, which is a concept that blows my mind. For a clearer view of what I'm talking about, the part can be seen here and here .My questions are:

1. What is the concept behind this system? I was stunned enough by the fact that oil is going into the radiator but to find out that the other end goes into the transmission- huh?

2. Are there any tricks involved in replacing the lines? I assume I'd have to drain the oil before replacing but would I have to drain the transmission too?

The transmission oil cooler is built into the passenger side of the radiator. It's more effective than just a stand-alone oil cooler.
You don't need to completely drain the transmission when you replace the cooler lines, but you will need to replace any lost fluid.

it's a pain in the ass to get the new lines to seal

i recommend hydraulic 45 degree flare copper seals if you have any issues with leakage at the connections after replacing the lines

get the trans lines from www.rockauto.com

Just an update: I found the lines for $30 on ebay (free shipping) and installed them yesterday. Working around the ends that go into the radiator was a bit tight, but not really too bad. The other ends simply pop into openings but they are held in by a plate that is secured with a 10mm nut (you have to use an extended socket). Now, that was a real pain to get to, but I was eventually able to loosen it and remove it by hand. The new AC Delco lines weren't exactly shaped like the factory lines so the upper line is now uncomfortably closer to the fan, but everything worked out in the end and no oil was leaking when I turned the car on.

Good that you got it fixed.

Any pics of how close to the fan the lines are? I'm curious

No picture right now, but it is extremely close.