Hey there,

I just noticed that during my last oil change the mechanic had used 5w30 synthetic oil. They are telling me 5w30 can be used and 0w40 is too thin.

What are your thoughts?

where was it? are they reliable? do you have a 2.0turbo? shouldnt be a problem though, as long as its full synthetic.
i do my own oil changes and have used different types. i think the very first oil was 5w30 or 5w40 and then i switched to mobil 1 0w30 cuz it supposedly gives better gas mileage. i dont think it did but it didnt hurt anything either. now i use mobil 1 0w40. its the best for me since i have minimal burn off with it and i can get it cheapest at walmart. i live in ny with cold winters and have the 2.0t so the 0w is good for cold starts and the 40 is good for the high heat with the turbo.

Audi recommends a 5w40. The 30 isn't as resistant to heat, and since a turbo runs hotter, Audi recommends a 40 which has a higher heat rating to give the engine that extra measure of protection.

As 5W30 is thinner than 0W40 you need to find another mechanic who at least knows the basics of lesson 1 of mechanic school.