I purchased an older A6 quattro to get me thru the winter while I do my 250,000 mile service on my TTS-Line Roadster ('04). BUT, I have an oil leak that must be just above the oil cooler. I have replaced the oil coolerr with a new one, And a new O-ring. Torqued correctly to 18 lb ft of Torque. After engine gets warm, oil starts leaking between the cooler and the block. But it does not seem to be coming from the oil cooler itself.

Can anyone tell me if this era car/engine is known for oil leaks in that area, and what it might be? It seems to be pressured, as it drips reasonably fast, like its being pushed out, as if under 'pressure'. Please advise. Thanks.