Re: oil change frequency
The 3,000 mile oil change rule is a waste of money and natural resources. Was put in place by the advertising campaigns of oil companies years ago and they did a very effective job of brainwashing the public. No manufacturer recommends such frequent oil changes except for the most extreme of driving conditions. I change oil & filter every 7,500 or one year, whatever comes first. Sometimes I stretch it to about 10K. I keep my vehicles usually to about 150K to 200K and have never had a lubrication problem, no sludge in the engine, and no oil burning problem on any. I run Mobil 1, but believe that regular petroleum oil would handle this interval fine, too. <br /><br />The only time I'd recommend anything more frequent would be if the vehicle is run for very short trips (for example a daily work commute of 10 minutes or less) on a regular basis, because under these conditions moisture will build up inside the engine and it never gets warm enough to evaporate out. Causes water to pool in the bottom of the oil pan (oil floats on water). Many a "little old lady's" car has had oil pans rust right through from the inside due to this problem...I remember replacing a number of oil pans on 10 year old 30,000 mile cars when I ran my own shop years ago.<br /><br />Incidentally, K & N air filters do absolutely nothing for stock vehicles. If you do other mods that allow the engine to pump more air (head porting, etc.), then you may need more airflow that a K & N may help. But if a filter and maybe exhaust system are your only mods, the same old stock engine still can't pump any more air through it than it did with the stock filter and exhaust, so usually a waste of money. They also let more dust through and don't filter quite as well as disposable paper filters. I run K & N's, they're a good product, but only in my modified race cars.