I’ve previously written on this subject but it always seems to come to my attention on a regular basis as a shop owner.  Recently we have seen vehicles whose owner either neglected to pay attention to the industry standards for oil change intervals, were misinformed about how often it is necessary or just didn’t care. To complicate matters the oil industry has changed much in the last decade as well as the internal combustion engine and its tolerances.

Most manufacturers have increased their oil change intervals to 5000 and 7500 miles. BMW had a recommended interval of 15000 miles but have since rescinded that to a 10000mi interval.  They are also using an extremely high quality synthetic with a fleece filter canister system. The thought here is that 15000 was way too long and engines are showing serious wear after 60 to 100000 miles. http://f30.bimmerpost.com/forums/showthread.php?t=868291

One thing to keep in mind from the standpoint of the automobile manufacturers is that it is not in their best interest for you to keep driving your car for 250000 miles. Having said that I realize it is also in the oil industry’s best interest for you to change it more often.  So how often should I change my oil?

I will try to answer with the most common sense approach keeping in mind that what I see on a daily basis after 40 years in the industry influences my opinion on the subject. What we see time after time is sludge build up within the engine or lack of lubrication causing engine damage.  Some engines tolerate a longer interval than others but how do you know? Well, you don’t. Our recommendation is 3-5000 miles for conventional oil and 5-7500 miles on synthetics with a quality filter.  Honestly oil is still not that expensive compared to major engine work on today’s modern vehicles so there is no reason to skimp on oil changes. Most reputable shops have recyclers pick up their used oil and reuse it so it’s not as big an environmental impact as some would make it out to be.  I’ve also read in other blogs on the subject that companies just want to get you in for more oil changes so they can sell you more work. If you feel your service provider is of this mindset then you are having your vehicle serviced at the wrong place.  You should have a sense of trust that your automotive facility has you and your vehicle’s best interest in mind and strive to always give you the best service at the best value for you, the customer.

Here is a link to the petroleum quality institute where you can read about the various types of oil qualities and their properties.  http://www.pqiamerica.com/Labels.htm

Below are some recent pictures of engines where extended oil changes were a factor in their lack of longevity. One is a Honda camshaft replacement, you will see the old cam with the new one alongside it. Notice the wear the lobes have compared to the new one.  The other pictures show how sludge can build up in a neglected engine.