Your rates of bank

Like a lot of people, you may be watching the price at the pump soar and wondering whether it’s time to dump your current, less-than-efficient SUV, truck or car.

It’s tempting to simply haul your 15 miles-per-gallon vehicle down to the dealership and drive out in something that gets 30 mpg or more. But that may not be smart, at least from a financial point of view.

People thinking of going this route need to take several factors into account.

For starters, your gas guzzler is worth considerably less as a trade-in than it was even six months ago. By some estimates, the value of used sport utility vehicles has dropped more than 20 percent since January.

Even if your current car is paid for, you’re likely to incur new monthly payments on that fuel-efficient replacement.

Finally, it could take years to realize actual savings at the pump when other factors are taken into consideration.

Here’s an example:

Suppose you have a two-wheel-drive 2001 Ford Expedition XLT. According to Edmunds.com, it is worth about $5,700 as a trade-in and gets about 16 mpg in city driving, although most owners of that model know real-world mileage is less than that.

At $3.70 a gallon for regular fuel, it costs about $97 to fill the Expedition’s 26-gallon tank.

To cut that bill, the Expedition owner is looking at a two-wheel-drive 2008 Ford Escape Hybrid, which can likely be bought (assuming reasonable options on board) for about $28,000, plus taxes, title fees, etc.

The Escape Hybrid promises to deliver about 32 mpg in normal driving, double what the 2001 Expedition delivers. A fill-up of the Escape’s 15-gallon tank at $3.70 a gallon would cost about $55.

But what are the real savings?

Assuming you own the Expedition free and clear and use the trade-in value as your down payment — and cover the sales taxes and other fees in cash — the Escape will come with a loan for about $22,300. At current rates, financing for 60 months means a monthly payment of about $439.