How often should I change my oil? This is one of the most common questions we get related to caring for our vehicles. The short answer is that the old adage of "3 months or 3,000 miles" is still true. Let me explain.
If you have looked at your car's owner's manual (I know, how boring), and your car is less than 10 years old, it probably tells you to change your oil at 5,000 or even 7,500 miles. Those figures are based on the fact that today's motor oils are much better than they were 20 years ago; or even 5 years ago, for that matter. The issue that still exists, however, is that the inside of an internal combustion engine is a violent, dirty place. Motor oil takes a serious beating. While its primary purpose is to reduce friction on moving parts, it also takes away the dirt and grime created by combustion and daily operations so the engine will last longer. Your oil filter can only remove so much of the dirt and, eventually, your oil gets dirty. In fact, it gets dirty long before is loses its lubricant properties. While you CAN run beyond 3,000 miles, most people who really understand engines (and we think we do), recommend sticking to the 3,000 mile rule.
Before the skeptics out there say that this is just a money grab on the part of auto care providers, please understand that we don't make dime on a typical oil change. It would be more profitable for us to recommend longer oil change intervals and then perform the major repairs that result from the damage done to your engine. However, our job is to care for you vehicle so that it is safe and reliable when you need it to be. For that reason, we want to see you every 3,000 miles. It's the best investment you can make in the longevity of your vehicle (along with a car wash). The longer your car lasts, the longer it will be until you need to buy a new car. That saves you a bundle in the long run.
Should I be using synthetic oil? This is a great question. The short answer is to use the grade of oil that the manufacturer put in it when it was built. If it came with synthetic, absolutely stay with that. Usually, people want to know if they should switch from conventional motor oil to synthetic. Here are a few things to consider.
First, synthetic is usually double the cost, at a minimum, of conventional oil. Will it lubricate better? Yes. Synthetic is very slippery stuff. Will it last longer? Yes, but see the answer to the question above. It still gets dirty. You will have really slippery, really dirty oil in your engine. Not a great plan, in my mind. If you don't mind the extra cost, go for it.
Second, how old is your vehicle? If it has under 100,000 miles and a lot of highway miles (usually gentler miles), you probably won't gain much from synthetic. If it is over 100,000 miles and it came with conventional oil, I would rather see you put a "high mileage" synthetic blend in the engine, instead.
Third, how has your vehicle been driven? If you have a high mileage vehicle used in stop and go traffic or used for heavy towing, synthetic may help your engine last longer.
Washing your car. As I mentioned above, that is one of the two best things you can do for your car. I know, "why is a mechanical shop interested in how clean my car is?" Trust me, I have a good reason. Every Spring, we see cars that have been coming to us for several years show up for an oil change or a repair and we see significant increases in the amount of rust on some and not on others. They all drive on the Iowa salted roads. The difference? Regular winter car washes with under-body flushes.
Why should you care? Some of the most critical safety items on your car are on the underside (shocks/struts, brakes, springs, the frame). If you allow salt/brine to just cling to the car all winter year after year, it will have a very negative cumulative effect. Not only will parts need to be replaced sooner (a cost increase), but it can put your family's safety at risk. Get regular car washes on winter days with a high above 32 degrees...and spend the extra $2 for the under-body blast!
Should I use ethanol-based fuels? OK, I will be brave here in farm country and tell you that the benefits of using ethanol-based fuels are not as cut and dried as the corn industry and politicians would have you believe. I am not going to wade into the argument about energy used to produce ethanol vs. energy created. I am not even close to qualified to do that. What I will tell you is to do your own testing and decide for each of your vehicles if it makes financial sense to use ethanol-based fuels. Simply measure your fuel economy with 2 tanks of straight gas and 2 tanks of whichever ethanol blend you are considering. Here is how to compare. In our area, 87 octane E10 (10% ethanol) costs $2.19. 87 octane straight gas costs $.20 to $.40 more per gallon. That amounts to just over a 9-18% additional cost per gallon to use 100% gasoline. If your gas mileage improves by more than 9-18% when using 100% gasoline, then it is less expensive per mile to use straight gasoline. In our cars, we get 12% - 14% better mileage on 100% gasoline, so we don't use ethanol-based fuels, if we can get it at the lower end of the price spread. Again, come up with your own facts and decide for yourself.
1910 St Andrews Ct NE, Cedar Rapids, IA 52402, USA