I am going to start off by saying: READ YOUR OWNERS MANUAL. Do not listen to what the car salesman told you. He sells cars, versus fixes them, for a reason. Probably because he doesn't know a piston from a cv-joint. So since we agree that his job was to sell you that car, I think you too can agree that it wouldn't NOT have been in his best interest to tell you the truth regarding the PROPER maintenance of your vehicle. Maintenance is nowadays calculated into the overall cost of ownership, and if an salesman told you the truth about the proper maintenance, you probably would have stood up and left the showroom, for a dealership that claims their cars dont cost as much as much to maintain. Throw out everything you 'think' you know, about changing your engine oil. Keep reading, I assure you, you will walk away much more knowledgeable than you did at the beginning of this article.
Oil Filter: OEM, Aftermarket, Extended Drain? An oil change consists of more than just draining & refilling your oil. It also requires your oil filter to be replaced. Simple, right? Not really- SINCE NOT ALL OIL FILTERS ARE MADE A LIKE!
How do you know the filter you are using, or getting, is built to withstand the extended intervals you are now exposing your engine too? Did you really think that just because your oil is made to withstand 15,000 miles, that your filter was too? Well if you did, you are dead wrong. Oil filters are not all created equal. Some use glue to hold the pleats together, while others use staples. Some have more pleats (the folds of filtering media) which give more surface area, thus increasing filter life. Some have a nice uniform amount of pleats per inch, while other cheaper filters have irregular pleats, which quickly deform. Which are you using? If you cant answer that question, I'd highly suggest getting a filter and taking a look inside.
Some filters clearly express the ability to be used, in extended drain intervals. While other dont say anything at all, hoping you dont know, and use their product simply because its the cheaper alternative. Well I am here to tell, you that your filter, needs to be able to withstand the specified amount of miles you intend to drive - otherwise you are driving around a ticking time b*mb. If and when your filter fails, and it does happen a lot more often than you'd think - it has a special "by-pass valve" inside that takes the incoming dirty oil, and routes it past the filtering media, and back into your engine, unfiltered. Thats right - its as if you dont even have an oil filter at all. There is no sensor, check engine light, nor noise, that will alert you to when this happens.
My advice: if you are going to drive anything further than 5,000 miles: buy an extended oil drain filter. Spend an extra $3-$5 and know, that you are not causing irreparable damage to your engine.
Engine Oil: Conventional? Semi-Synth? Fully Synthetic? Conventional: this is your basic oil. It has come such a long way, that its almost unnecessary to use synthetic, unless you are putting your engine through stress, or you live in Arizona, and drive a turbo motor. I use conventional, 75% of the year, on all my cars, and its never caused a single oil related issue. Semi-Synthetic: This is the best of both worlds. It gives you the cost savings of conventional, while maintaining the longer lifespan of synthetic. The downside, is its often hard to find, which in return drives the retail price of the item. I personally create my own "semi-synth" by mixing conventional(5w-30) and fully synthetic(0w-30) pre winter for a really light oil, that will flow MUCH easier during those harsh, below zero, mornings. I will get into the "oil weight numbers" below, so dont worry. Keep reading. Fully Synthetic: This oil is great. Its the bee's knees. Its the oil you want if you are towing, racing, or you own a turbo engine, in hot area's. Arizona, New Mexico, Florida, etc. Actually, if your summer's are over 90F you should be using fully synthetic, in your TURBO engine. Turbo's spin at 100,000 - 200,000 RPM's and they require some super high quality oil. I'll discuss this in more detail below, so keep reading.
Mixing oils: Its totally 'ok' to mix the oils together. One will not affect the other. In fact many "synthetic" oils have conventional oil as its 'base-stock'. In the winter, your oil will get thick. The thicker the oil, the harder it is for the engine to pump up into the engine (oil sitting at the very bottom, in the oil pan). So for the first minute or two, your engine could literally be running oil-less. You can help your engine, by using a lighter-weight oil. I do it. In fact, around October, i will do my regular oil change and refill the engine with 50% (conventional 5w-30) and 50%(synthetic 0w-30). Why you ask? This way you effectively reduce the cold weather thickness of the oil. Keep reading, i promise you'll get it!
Oil Weight: 0w-20, 0w-30, 5w-30, 5w-40, 10w-30, WTF!? When you see those numbers, do you really know what that means? Do you know what your engine, "requires"? (it will be written in your owners manual, and usually the oil fill cap). YOU WANT A THIN OIL WHEN ITS COLD OUTSIDE, AND A THICKER OIL WHEN ITS HOT OUTSIDE. When you hear oil weight, that doesnt mean how much it weighs, in pounds or ounces; rather it means how 'thick' it is, during cold weather(the 1st number with the "W") and in hot temperatures(the last number). The larger the number, the thicker the oil will be. Think of maple syrup being a 100weight, while water being a 0(zero) weight. Get it? Good. So why the 2 different numbers, you ask? Well because when you walk out of your house at 8am, to go to work, your car engine is cold, and so is the engine oil. The colder the oil, the thicker it will be. Every oil is designed to be a certain thickness, at 0F, and then again at 210F(running temp). That being said, the thinner the oil, on a cold morning, the better. BUT you dont want thin oil when the engine is already hot, because thin oil can turn into a tar-like substance(commonly known as sludge). So chemicals have been installed into engine oil (called additives), to cause it to thin out when cold, and thicken up when hot. Which do you pick/want?
You can simply stick with the manufacturer specified numbers. If your car cars for 5w-30, use it. But you dont have to lock yourself into that number. you can use 5w-20, and be fine too. You can even use 0w-30 and be in great shape. Just dont go to thick. Thick oil is hard for the engine to pump. That will decrease MPG's, and possibly cause premature oil pump failure. Manufacturers make cars, that are the average of all climates. So if your climate is crazier than the average (Canada for example) then you can, and should amend your oil weight numbers to what suites YOUR location best. Where I live, we see 5F winters, and thats brutal on 5w-30 engine oil. My engine oil gets really syrupy, and thick. This is why right before winter, I stray away from the manufacturer specified 5w-30, and choose 0w-30 instead. I want the thinnest possible oil in the very cold brutal mornings, and yet i want to stay in the 30weight once the engine reaches normal operating temps so i dont put any further stress on the engine by having too thick of an oil.
My advice: Every fall, drop down the FIRST number by 1. So if your engine calls for a 5w-30, you can and should drop that down to 0w-30. It will be a HUGE help to your engine to have light weight oil in the cold brutal mornings, and yet have the same oil thickness once warm. If you drive a turbo engine: you want light weight oil in the cold mornings, and a high quality oil in the summer. Once your turn off your engine, your turbo will continue to spin a few more thousand rotations. By turning off your engine, you also cut off the oil pump - and the problem that starts to happen, is the remaining oil in the bearings of the turbo will begin to absorb the heat. Low quality oil can turn into sludge, or will poorly lubricate your turbo bearings.
How often should you change your oil? 3,000 5,000 7,500 15,000 miles? Did you know that once you turn off the engine, the temps begin to rise? Yep, its true. Engine coolant helps cool your engine. So when you turn off your engine, your coolant pump shuts off too, and if the coolant pump shuts off, how do you expect to cool the engine? Thats why its essential to have clean, high quality engine oil. Especially if you have a turbo motor. Dont buy into the hype that everyone can drive 15,000miles without changing your engine oil. Everyone's driving style is different. I drive normally, while my father drives with a heavy foot. Turbo engines require fresher oil, while normal engines can get away with older oil.
Also, if you live in Arizona, your engine oil gets beat-up by the hot ambient temps(on top of an an already hot engine) faster than the guy living in Oregon. And since oil is hygroscopic(absorbs moisture), you better be changing your oil more often if you live near a humid area (i am talking to you Seattle, Miami, jersey shore, etc). So you should really think about your oil change interval, on a more scientific scale. One size will NOT fit all. dealerships are salivating at the thought of having you come in with a blown turbo, motor, etc- after 60,000 miles(when most warranties end).