Q: THIS IS MY FIRST TIME USING FULL SYNTHETIC OIL AND IT IS MAKING A HUMMING SOUND AT START UP. DOES ANYONE KNOW IF THIS IS NORMAL SINCE MY MOTOR IS NOT USED TO FULL SYNTHETIC OIL? IS THIS NOISE BAD? OR WILL MY MOTOR EVENTUALLY GET USED TO IT IN TIME AND WILL THE SOUND GO AWAY?
A: your car should have Always been on full synthetic especially with the turbos. See the post i linked. your engine requires SYNTHETIC oil ONLY and it should be 0w40 or 5w40 they run at high RPM's and high temperature's so they need an oil that can withstand both. they also need to be Audi certified 505.00 or better or be an ACEA A2 or A3 spec oil. most 5w30 oils both conventional and synthetic by most manufacturers do not meat those requirements. Audis engines require a high-temperature/high-shear viscosity of 3.5 cP or greater. the majority of 5w30 oils are below that (closer to 2.9-3.2 cP) even when running the correct weight (5w40) you need to look for the certifications.