My Gas Mileage Went Down The Potty.

[kgh31386]

I usually put 5W30 oil in my car, but Walmart decided to put 10W30 in it. Is that going to affect my gas mileage? Something is, I filled it up Friday night with gas, I'm at half a tank now. I didn't drive that much this weekend. What should I do?

[SRK]

A 10W-30 oil will decrease your fuel mileage - but by an amount you will be unable to measure. It is very slight.

Drive several tanks of fuel noting the mileage and fuel added at each. Find the average per tank, and total them and find the amount over several tanks. You need a measured baseline to be able to determine if the fuel mileage has dropped. Not a hunch.

[GuyTelefunken]

You get your oil changed at Walmart? Hope they didn't use one of those quality Fram filters. Good god, have a little compassion for your car. Avoid Chinamart at all costs.

I only suggest that Chinamart may have used a Fram filter because (in my area) that's all they stock. For a review of Fram filters, look here. Scroll down to Fram. Or here.

Note I'm not trying to bust ballz, but did you specify what oil Chinamart was to put in your car? If you did and they put something else in, why did you not tell them to change it immediately?