Your leak probably looks like this. It's a common problem. The lower rear pipe is located behind the engine. Buy the seals from Audi, as a few of the seals are high silicone content to handle the heat from the engine block.

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i am working on the above car v8 4.2 and replaced radiator due to a crash some time ago got it installed started filling noticed bad leak on passenger side upon further inspection found a freeze plug sitting above alternator can not see where is goes any help please and if one poped would there be others