I have made the mistake of letting brand name shops do oil changes on my 2011 Mazda3 2.5L and they have been putting what I am assuming is thier regular generic 10w40 or 10w30 at $2.95 a quart. I decided to get the equipment to start doing the oil changes myself and noticed the engine oil calls for 0w20 synthetic... Which I am assuming the car came with. Long story long, is this doing any sort of damage to my engine? Should I be trying to get ahold of the shops and get some sort of fix done?

Ive got oil changes done every 3k at 3 different shops since I have owned the car and I have 27k miles on it.

Thanks for your replies and your time,

Axel

 

As long as u dont have engine knock your fine. But the shops u tool it to shouldn't b changing oil if they can't read! It clearly says the oil weight on the cap. Though u could record a call to all of the shops so that if something does happen to your motor then u have some proof. U can skip the 3k oil changes. Mazda rec. every 5-7k I've always told my customers 5k. But do use the 0w-20 there are reasons that they use that now and not the 5w-20 they have used for over 10 years.