The value of proper car maintenance is priceless, but the costs may be rising. I recently went to my local service station to get an oil change and when I went to pay the bill, I was surprised by the price. Just a few weeks prior, I had brought in my other four-cylinder car and it was $7 cheaper. The attendant explained that the price difference was due to the high cost of motor oil. From posting the weekly gas prices, I am intimately familiar with the price fluctuations and have been feeling the pain at the pump like all motorists. It was only a matter of time before it was reflected in an oil change, though it surprised me that it occurred over such a short time period. A colleague who also just had an oil change performed reported prices at his shop hadn’t increased. Perhaps I picked the wrong shop, or it may be a sign of things to come. (Share your recent experiences in the comments below.) Given the dramatic rise in crude prices, it makes sense that petroleum-based products would see their prices increase, though many service centers may struggle to minimize the consumer impact due to competition and drive to upsell other services. At any cost, oil changes are a critical part of maintaining your vehicle. For normal driving, many automakers recommend changing the engine oil and filter every 7,500 miles or six months, whichever comes first. This is sufficient for most passenger vehicles. For "severe" driving—with frequent, cold starts, short trips, dusty conditions, or trailer towing—the change interval should be shortened to every 3,000 miles or three months. (Check your owner’s manual for the specific intervals and oil weight recommended for your vehicle and use.) Special engines such as diesels and turbocharged engines may need more-frequent oil changes. Another important maintenance check is tire pressure. Under-inflated tires compromise handling and braking, wear faster, and reduce fuel economy. Plus they run much hotter, which can lead to tire failure. In our tests of a Toyota Camry, we experienced a 1.3 mpg loss in highway fuel economy when the tires were under-inflated by 10 psi. To find your vehicle’s correct tire pressure, look for the placard on the inside of the driver’s side door. The inflation pressure listed on the sidewall of the tire is the maximum inflation pressure but is not the recommended inflation for the vehicle. Stick with the recommendation for the vehicle—it is designed to provide the best interaction with suspension components of a car for the best balance of ride and handling. By filling tires to the maximum listed on the sidewall, it could adversely influence handling, as it would tend to pull the edges of the tire off the pavement. In other words, you would reduce the amount of rubber on the road. As you round the tire by adding additional air, you may also see an adverse consequence on wear, since it will tend to wear the center of the...