My Volvo turbo is all gummed up, it has excess crankcase pressure and is seeping oil past the turbo seals.
A mechanic, decided that he knew enough about oil and chemistry to change my oil during a clean air test. Out came the Mobil1 15w50, in went one of the advertised 5w30, synthetics that is actually not synthetic. Unfortunately, if a dino oil is refined enough, a company can legally call it a synthetic.
Can I get the shop to fix it? No! Wrench turners are firm in their belief that they know about oils. They know everything about oils.
I am posting this for the benefit of all. Do not ask a mechanic, auto store clerk, quick lube guy etc., about oils.
Do not believe what an automotive lube sales rep from a big oil company says. They are business grads, not engineers or chemists.
Ask a qualified individual (engineer/chemist)from a reputable oil company. The big lube manufacturers usually have a 1-800 number for this purpose. Do not be shy! Ask the person you speak to about their credentials.
Otherwise ask questions on this forum. If I, or one of my associates does not know the answer, we will point you to an appropriate source.