In the CARCHEX series finale of “Stump Pat” we meet a Baltimore local named Libby. A friend of Libby’s recently told her that she can get more fuel for her money if she fills her gas tank up when the air temperature is cooler. The reason being that cold gas is denser than warm gas. Curious as to whether she should take the advice of her friend, Libby turns to “America’s Trusted Mechanic” Pat Goss for answers.

Welcome back CARCHEX fans. This is another segment of Stump Pat. I’m Julia and we are here again in Baltimore Maryland’s sunny Inner Harbor asking people some tough car care questions to try and stump Pat Goss. Come Along!

My name is Libby. I’m from Baltimore Maryland. Is it true that during the summer time you should by your gas in the night or in the morning because its cooler?

Alright, to you Pat. What’s your answer?

Libby, buying gas morning, noon, or night makes no difference. Outside temperature makes no difference. Reason is, gas is stored underground where temperature is constant and even if it wasn’t a constant temperature the amount of fuel that would have to change temperature well it would take weeks or months for it to change substantially.

So, the only time where there is really a different is between oh maybe the middle of summer and the middle of winter, there could be a little bit of a difference. Other than that fill up whenever it’s convenient.

Well thanks for all the answers Pat! That concludes our Stump Pat series. If you want to find out more about CARCHEX visit our website at