Hello, I just bought a used 2019 opel insignia b with 180 thousand km which has the same engine (gm 1.5 ecotec turbo) as the on in the chevy Malibu, i was wondering which oil to use, when i bought it i serviced the car the same day at the dealership, they put 0w20 oil in it, they didn't fill it up all the way to the second mark of the dipstick, they filled exactly between the first and second mark, after using the car for 5 thousand km, i checked the oil level and it was a little below the previous mark, i then checked the spark plugs they had carbon deposits but where completely dry, I am currently wondering if i should keep using 0w20 or should i change to 5w30 considering the high milage, and the hot weather ( car is in egypt) and also the little oil consumption, what is your opinion, i am not suffering from any problems i just want the best for my car.
Thank you, Regards
The relevant information is in your owner's manual.
It's best to stick with the oil recommended by the manufacturer. Using heavier oil for hot weather and worn engines is an old trick from decades ago. (It would be standard procedure for something like a 1965 Chevrolet.) It isn't really applicable to modern engines which require specific oil viscosity due to features such as variable valve timing.
