My teenaged son–a budding auto designer–is convinced that synthetic oil is worth the extra cost. Though I have no data, it seems unlikely to me. Is there any independent data I can cite (or ignore, if I’m wrong)?
Similarly, he insists that changing oil brands is bad for your car. That seems patently false, since it would lock you in to whatever oil was first used. Any kernel of truth there?
I would think so too. How could a different brand of the exact same spec motor oil be “bad” for a car?
Too broad a scope. Worth the cost, even if he’s only leasing for two years or 24,000 miles? Or does he want to buy a car and keep it for 300,000 miles? What kind of car? Does the OEM require synthetic oil? What are his driving habits? What’s he pay for synthetic versus mineral oil (which still can have a lot of synthetic components)? By budding auto designer, does that mean engine systems or does he only get to choose the font for the multi-function switch coming off of the steering column?
Oh, that last question may not be relevant. 
The question SHOULD be easy. . .can you get 15,000 out of that synthetic and only 5000 out of the regular, and is it within 3 times the cost?
I used to think that, and I went with synthetic so I didn’t have to change my oil so much. Only, it seemed to get low in about the same time frame AND I didn’t notice any sort of performance or efficiency gains. So, I switched back to regular.
YMMV. (appropriately)
Your hunches, Chimera, and Balthisar are all correct. The myth about not changing brands is a holdover from the 1940’s*. Whether synthetic oil is worth the extra cost for an engine that does not require it depends upon many factors and defies a “one size fits all” answer.
*To expound a bit, when detergent motor oil was introduced it was the gee-whiz technological innovation, so naturally some people started using it in cars that had been run for quite a while on non-detergent oil. Unfortunately, in some case the detergent additives loosened up-till-then benign deposits of sludge which proceded to clog up vital oil passages and cause major engine damage. As a result, the word got out to not change types of oil. This mushroomed into “don’t mix or change types, brands, or viscosities,” which was an overreaction even then. It did have its kernel of truth 60 years ago, but those days are long gone. However, like many disproved urban legends, it has continued to be propogated and believed by those who don’t understand the facts behind it.
Well, on another oil-related board (PM me if you want to know), the general wisdom is that any API SM rated oil is good for most manufacturer’s recommended intervals, up to and including 7500 miles.
The general wisdom is that with regular oil and filter changes, your engine will outlast the rest of the vehicle. (my experience too)
Synthetics are generally regarded as useful if you:
[ol]
[li]Live somewhere extremely cold- very cold parts of US, Canada.[/li][li]Do something extreme like race, pull trailers in the Rockies, etc…[/li][li]Are paranoid[/li][/ol]
Note: Extreme != summer in Texas, winter in Nebraska, etc… It truly means extreme in this context, not on the high end of normal. Towing a U-Haul isn’t likely to be extreme unless you’re pulling it with a vehicle not meant to tow, and you’re towing something really heavy.
Of course there are a million caveats over on the other board- certain engines need synthetic due to sludge production, some manufacturers recommend them (use them in that case!), etc…
Consumer reports did a test with taxis changing the oil in 1/2 every 3000 miles and the second half ever 6000 miles. They found no difference in wear between synthetic vs regular or 3000 vs 6000 miles. They drove the cabs for 60,000 miles.
Years ago, low-viscosity oils were being promoted as a way to increase gas mileage-DSATURN used to specify 5 W 30. Now they are back to 10 W 30-does this mean that the low viscosity stuff increases engine wear?
I didn’t think to specify because I doubted that synthetic oil made any significant difference. His car is an ordinary 2003 Grand Prix. But maybe an answer depends on too many factors to be meaningful. Personally, in that case, I’d just take the cheapest route.
Thanks for the link. The article is excellent and interesting.
Bolding mine. Is that a whoosh? If your oil is getting low, you’ve got a leak or are burning it somewhere. It’s not dependent on the type of oil you’re using.
It comes out your tailpipe smelling like witch hazel. Wish they had a motor oil that came out smelling like butter and garlic!
I don’t beleive it is. Some engines require a synthetic oil, so it must be used in them or it will void the warranty. The ones that don’t require it it’s a waste of money in my opinion. I knew an open class race car driver that ran in the SNORE/SCORE races back in the late 70’s early 80’s. He ran an open wheel VW bug, a class one vehicle I believe it was, that had a 1600 cc air cooled VW engine in it. It is some of the dustiest hardest terrain around, like the old Mint 400 race that ran here in southern Nevada. Anyway this guy only used regular oil, either Valvoline race oil or Castroil in his cars. The engine had a roof mounted air cooler, no electric fan just a custom duct/scoop he made from fiberglass to catch the air coming over the top of the bug, it added about three extra quarts for a total of eight quarts. Although he never placed high in the standings, he was a small bug repair shop owner, so he didn’t have the dough like the big guys did, but he never failed to complete a race. If regular oil is good enough to make it through that kind of environment, in an engine that has steel, aluminum and magnesium parts in it, its fine for pretty much any factory engine I’ve ever seen. Not counting the ones that require synthetic, or have oiling systems that need low viscosity. Too much ado is made about using synthetics, once you start it you can’t stop it, the blended sythetics, etc. If it has an SAE rating on it, it’s good enough for a factory engine as long as you change the oil. So many people let it slide and the motor gets sludged up and after that it’s only a matter of time before it all goes south.
You think that was a joke huh? Chrysler made an additive to improve the smell of oil in the Cummins engines. I shit you not. Part #5139947AA. Makes the oil smell like lemons.
Speaking as a guy that crewed on a SCORE truck back in the day, you are missing one very important part of the equation.
Your buddies buggy (not class 1 if he was running a `1600 VW motor BTW) got its motor torn down and rebuilt after every race. Most of us driving street cars don’t rebuild their engines that often.
Also a 1600 CC bug motor is not zactly what I would call state of the art. It was state of the art in the 1930s.
Getting back to the OP, switching oils brands is a old wife’s tale. Synthetic oils can and do offer some advantages. Whether or not you and your car will benefit from them depends on your car, where you live, and how you drive.
Did you miss the part about him being poor? You’re gonna laugh about this shit. He stole one of those big exit signs from the side of the road, one of the ones painted green with reflectors around it because he needed a front skid plate and didn’t want to use steel. Plate steel still being reasonable back then, aluminum, not so much. Man, you should have seen it on his bug! It was so damn funny! He had his front suspension sprung where it had the maximum travel and you could see the green on the sign when you were looking at the wheel from the opposite side of the car. I almost passed out I was laughing so hard. He looked at me and shrugged his shoulders and said “What!?” real sheepishly. Before I forget, my hats off to you sir ! I can remember being at the Mint race, we would camp along the track in tents, usually by a particularly nasty drop off or river bed to see some action, and man, it was dusty as hell. I can remember having to keep my bandana soaked every 15 minutes or so to keep the dust out of my throat. O.K. man, just one more tidbit. We were all sitting around the campfire one year next to my van, a 1971 Econoline (Yes, it made it onto the track!) drinking beer the night before the race. One the ladies is sitting by my rear tire and stands up all surprised and says, You know you have a nail in this tire!? We were almost drunk and everybody looks at each other and says Shhhhh!! don’t even look at it.
Sorry for the high jack. Again just changing your oil on a regular basis is so important. Brands seem to be like just that, brand preference. As long as you change it regularly, and check it like your supposed too. It’s not unheard of to be able to see when something like your PCV valve is sticking by simply checking your oil every few weeks or so. You can spot condensation on the stick, oil seeping out around the grommets on the valve covers. I don’t know though, a lot of manufacturers are using appearance covers over the top of the engine so you can hardly see anything anymore. Still, looking under the hood can save you from other problems as well. Belts, hoses, battery cables and the like.
If I lived in a very cold region (Alaska) and made a lot of short trips and cold starts, I’d switch to synthetic if I were planning on keeping my car for a number of years.
After reading the article, I still will continue to buy any brand of oil that meets the recommendations in my manual and I’d go for a good price. I will still lean towards 5-6k between oil changes
Read the article and you should come to similar conclusions. I average 150k per vehicle, live in the NE USA and have never had an oil related problem. I used the same oil change methods with my old Shelby Z turbo, towing pickup, Jetta, Solara, Mustang GT…the list goes on. Anecdotal evidence rules! 
I’ve never lived in an area that had a normal climate like yourself. See, that’s why this board is so great, different perspectives. I get a little sketchy when mine goes over three and I’ve been inside many of my own engines so you get to see what they look like. I need to move ! Those kind of savings add up but I guess snow and salt are hard on the undercarraige so it’s always a tradeoff.
Slight hijack, but related:
Whatever happened to teflon products like Slick 50? I know they’re still around, but they used to be really popular, and it seems you don’t really hear about it anymore.
Was it ever shown that an engine treated with Slick 50 or a similar product was actually beneficial? Or harmful? Or just a waste of money?
The FTC sued Slick 50 for false advertising. Dupont who actually makes the stuff advises against using Teflon as an oil additive.