All cars need oil changes, but not all cars have the same oil needs. Older cars, in particular, develop unique needs for advanced oils and filters, and they sometimes also require additional attention. If your car has a lot of miles, make sure it's properly taken care of during an oil change by asking your mechanic these four questions.

How much oil was in my car?

Before putting new oil in, mechanics will drain out the oil that's in your car. Asking them how much oil was in your car will help you determine whether your vehicle is leaking oil.

Mechanics don't usually measure how much oil comes out of a car, but they'll have a rough idea if the car was full of oil or if it was low. If they say it seemed pretty full, then your vehicle likely doesn't have any serious oil leaks. If they say that it was unusually low, though, you might have a leak that needs to be addressed. Ask them to check around for a leak.

Of course, you could have a mechanic check for leaks anytime by bringing your car into their garage. It's easier to have them check when they're already working on the oil system, though.

Is there a heavier oil that's compatible with my car?

There are different types of motor oils, and they're rated based on their viscosity. As explains, oil ratings include two numbers. The first one is followed by a "w" and indicates the oil's viscosity at 0°F. ("W" stands for "winter.") The second number is the oil's viscosity at running temperature. In both cases, higher numbers correlate to lower viscosities.

Your mechanic may be able to slow minor oil leaks by using a less viscous oil, although they will still need to stay within the recommendations of your car's manufacturer. If you live in the Southern United States, they might recommend using 20w50 oil, which is much thicker than an oil that has 30 for a second number. If you live in the Northern United States, EHow notes, a 20w50 oil might make your engine hard to start in cold weather. Your mechanic might suggest a 10w40, which is still fairly thick and will be easier to start in winter, instead.

Will you use a premium oil filter?

As your car runs, oil flows through the oil filter. The oil filter's function is to trap dirt and debris that are in your oil so they don't damage your car's engine.

Just as there are specialty grade oils, there are also premium-quality oil filters. These premium filters trap more dirt than standard ones -- in one case twice as much. Because older cars are more likely to have debris in their oil than newer ones, high-quality filters are particularly useful in vehicles with many miles.

How much will the oil change cost?

If you're asking for a heavier oil and premium filter, the cost of your oil change will increase slightly. After all, these are higher-grade parts. Your oil change shouldn't become prohibitively expensive, and it's worth paying a little more for an oil change with premium materials. Nevertheless, you should find out how much it'll be up front so you can budget for the job appropriately.

If you drive an older vehicle, it may need a little extra care during oil changes. Ask your mechanic to watch and see how much oil comes out, and discuss which weight oil and quality filter is right for your high-mileage vehicle. If they recommend a special oil or filter, be willing to pay for it -- because taking proper care of your car is worth the additional cost.