Oil Weight ?

Hey everyone, my wife and I just purchased a used 2008 Aveo with 42,000 miles last Sunday. I understand that the operating manual says 5w-30, and I was under the impression that 5w-20 is a more standard weight for smaller economy cars in general that produces better MPG while still allowing for great wear protection, and in some cases even 0w-20 is used. Would 5w-20 or 0w-20 allow us to achieve higher MPG numbers while still offering optimal wear protection or should I just stick to 5w-30, thanks!

Welcome to the site daltron.

Changing to a thinner oil won't effect mileage that much. I'd personally go for a synthetic 5W-30 and change the oil every 10k miles or so.

However, if you are serious about wanting to use thinner oil, you can try it out for say 5k miles and then take a sample and send it in to a lab to get tested to see how the engine is wearing. I do this occasionally with my oil just to make sure the engine is in good shape. They can detect many things from the particulates in the oil (bearing wear, coolant leaks, bad air filters & more). I'd recommend blackstone labs. They have a lot of good info on their site:

Blackstone Labs

Cool, thanks!

Take a deeper look into the extended range oils offered by mobile 1 if you ever think about purchasing them. I've heard reports of people getting weird analysis of them. Like the 10k mile oil's viscosity will drop mid service and then return to spec at the end. So you take a new sample, checks out fine, mid change (like 5k), it's dropped below spec, then at 10k you're back in spec... pretty shifty stuff.