2003 A4 2.0L ALT engine. The Head has been done a week ago as well as having the Oil cooler pressure test. the Valve Guides were done, head machined and pressure tested. All test OK and installed with new head bolts and all new seal, gaskets, O rings, . It has been a week since the job was done and the Oil low light came on. the oil is in the reservoir.(dip your finger in the reservoir and its clean engine oil.)
Where else can Oil get into the cooling system?
Could it still be the Oil Cooler even though it passed a pressure test? e.g. crack opens when it's Hot