Who's the idiot: Tom and Ray, or Fred?

Dear Car Talk

Dear Car Talk | Sep 01, 2011

Dear Tom and Ray:

You recently answered a question about whether it's harmful to let your gas tank run down to empty. You said it's not harmful to the car, and it won't cause any damage. Eric Peters, a Washington, D.C.-based automotive columnist, recently stated in the periodical Bottom Line/Personal that, and I quote here: "Most gas tanks are made out of metal, and a partially empty fuel tank is prone to rust. Rust particles flake off and can clog fuel filters, fuel lines and fuel injectors, leading to costly repairs. In addition rust can eat through the tank causing leaks ..."

So what gives? Are you two right and still my heroes and this guy is an idiot, or is he right and you two are idiots? A curious reader wants to know.

-- Fred

RAY: Well, you already know we're idiots, Fred. But in this case, Mr. Peters' information is badly out of date.

TOM: In the old days, when tanks were metal and were vented to the outside air, rust and other particles were a problem. That's why cars had fuel filters -- to keep that stuff out of the fuel lines and injectors.

RAY: But for more than a decade now, most fuel tanks have been made of plastic. Even the fuel lines that carry the gasoline from the tank to the engine are now plastic.

TOM: Rust is such a non-issue now that most cars don't even HAVE fuel filters anymore. There's a "sock" filter on the fuel-pump intake in the tank -- in case an irate neighbor pours a plate of stuffed clams into your tank -- but that's it.

RAY: Plastic fuel tanks have a number of advantages: They weigh less, they're cheaper to produce and they don't rust.

TOM: And they may be better in accidents, too.

RAY: For a while, running the car out of fuel concerned us, because the fuel serves as the coolant for the fuel pump -- which sits at the bottom of the tank. But we really haven't seen any problems with fuel pumps to justify that concern.

TOM: So our opinion is, it's fine to run the car down to empty. If that makes you happy, go for it. Just don't call us to pick you up when you run out of gas, Fred.

Get the Car Talk Newsletter

Got a question about your car?

Ask Someone Who Owns One