I don't know about Audi having such an animal, buy my old 944 had an oil to coolant cooler. IMHO air to oil is much better, and is what Porsche did on the 944 Turbo (951). It was never pretty when somebody had a seal decide to let go or leak and oil and coolant mixed...... Samuel W. Clough Invesco Retirement Plan Services 404-575-3571