Vehicle: 2014 Audi A6 Quattro Sedan (4G2), V6-3.0L SC (CTUA), Automatically Shifted Manual Transmission/Transaxle

Mileage: 88,275 miles

Problem: The owner noticed that there was engine oil in the coolant and brought the Quattro to the shop to get it checked out.

Case Details: After connecting a scan tool, the technician noted that there were no diagnostic trouble codes (DTCs), so he ruled out a bad head gasket. He tried clamping the hoses at the engine oil cooler, but the coolant would quickly disappear during a pressure test. Then he remembered that every time he’d done a crankcase vent valve job, he would see coolant, so he removed the crankcase vent valve and found the gasket was ripped.

Confirmed Repair: The technician replaced the crankcase vent valve and gasket, pressure tested the system and found no more leaks. After flushing the cooling system, he drained the engine oil and refilled it with standard non-synthetic oil then used the engine flash machine. After he was satisfied the coolant was flushed out of the crankcase, he did another oil and filter change with the recommended oil and filter. After the test drive he checked the coolant and oil. Both were perfect. Problem Solved!