How great is the difference?

Not open for further replies.
Mar 5, 2003
When it comes to conventional motor oils, some are apparently better than other ones. People who have had motor oils tested at labs have discovered that apparently, to give two examples, Castrol and Chevron conventional oils are pretty good. How great is the difference between the best performing conventional oils and the worst performing? Is the difference so minor that it does not really matter, or is the difference significant? Could the use of a quality conventional oil as compared to a poorer quality one lead to thousands of extra miles? Are there motor oils so poor in quality that a person could safety drive only 2000 miles or so using them, while better quality oils might give 4000-5000 miles of service?
I think so. ExxonSuperflow according to Terry is great for wear up until 4k miles, and then the oil is depleted. I'd say there maybe a 2-3k mile variance between a bad dino and really good one. I'm only guessing though based on what I've seen on here. With dino, I'd just stick with 3-5k to be safe. Although there are many cars that call for 7,500 mile drains using factory filled conventional oil. [Smile]
I really didn't go back and relook at a lot of oil analysis. And its very difficult tell bc we are looking at different vehicles, driving styles, climtes, and then there are the abnormal conditions. But I think your question about 2000 for a substandard oil vs 4000 to 5000 is is a "yes" Thats probably about right.
Mystic this is a very good question, also what about the difference in wear between syn. and petro oil in their respective service duration extreme cold or heat would give the advantage to the syn. of course. There is the Diesel stop web site has a oil anaylsis posting and has enough to see trending and the wear on the syn. vs. petro not to be much if any difference but I'm not an anaylsis expert.
I can't imagine going 6000 or 7500 miles with any conventional motor oil, regardless of what a certain consumer magazine might say. I would be terrified to go that far with any conventional oil. But with good synthetic oils, of course, a person could probably go 8000 or more miles. But I think that there is probably a lot of variation between the best and the worst synthetic oils, as well. The worst synthetic may provide fewer miles of service than the best conventional oils. But the best synthetic oils would probably leave all conventional oils in the dust.
Hey, Steve S, what is this Diesel Stop web site where they have checked out motor oil? And did they find that synthetic oil does not really make a difference in wear compared to conventional oil?
Originally posted by Mystic: I can't imagine going 6000 or 7500 miles with any conventional motor oil, regardless of what a certain consumer magazine might say.
Based on what? My Honda 2000 Civic Si calls for 7,500 intervals for normal driving (5W30), and I usually change it around 7,250 to 7,400 with dino. Have 60,000 miles on it now. Everything is fine. Honda goes to what seems to be extremes on some things, like telling you to change the coolant and brake fluid at 35,000 miles. I am sure if they thought there was a benefit, they would not hesitiate to say 3,000 miles per oil change or to call out special oil...after all, they do require use of their own coolant. I am curious why you would not go 6,000 to 7,000 miles on conventional oil, if that is what the manufacturer recommends.
Mystic; CJH is on the money. I think any mainstream API SL oil will do you right at a reasonable oil change interval. You could close your eyes and pick one. Or go by color of the bottle, or what the name rhymes with. Or alternate even, odd & leap years. I use Pennzoil now but I might go to QS because they sponsor Terry Labonte [Smile] The point is, there are so many variables that will determine how long that Saturn of yours will last, so why wring your hands over oil, as long as you've got what Saturn calls for? All you'll do is ruin the enjoyment of actually DRIVING your car by constantly wondering how many ppm of iron you're up to, or how low your TBN has gotten. Too much irrelevant knowledge (and sales hype) can really suck the fun out of life. It's a good hobby if you are into the science of lubrication, but it probably won't actually impact how long you have that car. If you're not comfortable with the 7500 mi, go with 5K/6months. That way you leave yourself a little cushion (that you probably don't need) for the times that your driving is a bit "severe". Just remember that the best salesmen are the ones who can get you to pay too much for capabilities you don't need. That's where the profit lies, not in reducing the cost of producing products that are "good enough" so that more people can enjoy them. (**** , now I sound like a Communist). Good luck & buckle up. this is the link on my favorites but I don't know how to make it work? I originally found the link on . I lucked out finding it, I am not that computor savy. the link is fun to ponder oil and someone can find it and help me understand all the numbers fmtrvt put alot of effort out on this. [ May 01, 2003, 11:55 PM: Message edited by: Steve S ]
Originally posted by CJH:
Originally posted by Mystic: I can't imagine going 6000 or 7500 miles with any conventional motor oil, regardless of what a certain consumer magazine might say.
........ I am curious why you would not go 6,000 to 7,000 miles on conventional oil, if that is what the manufacturer recommends.

No doubt a lot of what many of us as consumers do is based on tradition or other beliefs that the marketers have drilled us on over the years. It would be hard for me to also go 6-7k miles on conventional oil even when my 1983 owners manual suggest 10K miles for the "normal" drain intervals. That seems almost unbelievable especially when you consider that was back when "SF" was the latest API grade. Perhaps Toyota and others make some of these recommendations to get one through the warranty period but not really mindful for those wanting to double or triple those numbers. But you make a good point about Honda recommends a specific coolant, so it would seem they could recommend a specific oil if it was a big concern. We just don't have the history of people running 6-10k miles on conventional oils to see what really would happen over the vehicle's lifespan of 10-15 years or so.
It has been my experience with new cars that a 7500 mile oil change is recommended for 'normal' driving, and 3000 mile oil change for severe service. Unless a person is a traveling salesman just about everybody qualifies for the severe service.
Mystic; Most, but not all. My volvo calls for 5K "severe", and my chevy has the oil life system, and says to change at 3K only if you drive in very dusty conditions. The point is, read the manual and do what it says. If you drive "mostly" under the conditions they say for severe service, then follow that interval. If only some of the time, then shorten your interval as much as you feel you need to (that's why 5K might be a good compromise if you do a mix of driving). Just don't blindly accept the Jiffy Lube / oil maker mantra that "everybody drives under severe conditions". If severe conditions were normal they would call them normal. That Consumer Reports study was seriously flawed (like few cold starts), but the one thing that we might be able to take from it is that "stop & go" driving and idling (once the car is warmed up) aren't nearly as bad as they want you to think. I think you should follow the manual. If everyone's cars start wearing out prematurely then there will be change. The way things are now, many people are changing their oil early (at 3K), and since cars are lasting a good long time, the car makers can say, "see, those 7500 mile intervals are working great! Lets go up to 15K!" And then the quick lubers will say "everyone drives under severe conditions, you MUST bring your car in at 7500". But, hey, at least they'll still flush your ATF every 15K miles for you too if you want. Getting back to your original question, though, don't sweat the choice of oil. Matt
Don't do what the manual says!! The manufacturer doesn't care how long the engine lasts as long as it lasts beyond the warranty period. What's in the manual is there as part of marketing vs. engineering. The manufacturer's want to hype low maintainence and you'll "take it in the shorts" if you follow their misguided advice. My GTP's manual says I only need to change tranny fluid at 100kmi, oil at 7500 mi, and never have to change supercharger oil. This is just plain rediculous. I did my first tranny fluid change at 30kmi and I'm glad I didn't wait one mile longer. If I used dino juice I'd never let it go beyond 4kmi regardless of driving conditions. (dino oil at $1/qt is too cheap to worry about). I happen to use Mobil 1 and change it out every 5kmi. I know I could push it to 6-7kmi but generally don't. (preventative maintainance is usually orders of magnitude cheaper than repairs so a little overkill is a smart decision).
Davefr; We'll just have to agree to disagree. I'm willing to bet some miles at the end of my vehicle's life to test the theory. Unfortunately, the whole argument is circular. No matter what I do, eventually my car will die. At that point people be able to say "See, if you'd done the maintenance more often it would still be running" but who knows if that's really true. Your car will probably last a good long time (due to your maint schedule or not), and you will be able to say "See, that Mobil1 at 5K worked". In the mean time, I'll invest my saved maintenance costs for my next ride. Matt
Why would a manufacturer what to Tee off a customer? If a car blows up just after the warrenty expires you can bet the customer won't be happy. Unless your customer base is a bunch of suckers you won't get repeat business.
Originally posted by davefr: ....... The manufacturer doesn't care how long the engine lasts as long as it lasts beyond the warranty period. .......
[ May 02, 2003, 10:43 AM: Message edited by: satterfi ]
One more thing (sorry for not letting this die). Davefr, have you seen Mobil1's advertising that it's good for the "maximum mileage or time recommended by the manufacturer"? By your logic (that manufacturers are trying to hype you with bogus recommendations to sell more product), wouldn't you think that the oil is really good for much longer than that, but they just want you to buy it more often? What is Mobil1's incentive to tell you NOT to change your oil so often? If you think they (the car manufacturer or the oil company) are lying to you, why use their product? That's why it's easier to just do what the book says, or a little more often if you want to feel better about it. Too hard to second guess the motivation of people on both sides of the issue who are trying to sell you something. BTW- I recently drained the transmission fluid out of my Chevy Impala at 50K. It had been a RENTAL car...but you could have eaten off the pan and drank the fluid it was so clean. I'm a believer now that a lot of this reliability/durability stuff is more "luck of the draw" than we ever imagined, and I don't plan to change the transmission fluid and filter again for another 90-100K.
This is an interesting thread. The following is a direct quote it: it comes from an engineer for MAXIMA Racing Oils, and was in Motorcyclist magazine a couple years ago. "Something to keep in mind: I would say that in general terms, even the best petroleum base stock we could buy is not as good as the worst (cheapest)synthetic available to us. We can use the right additive package to make the petroleum-based oil an excellent lube, but it starts out at a disadvantage. (In all areas but one: cost.)" Also... "Synthetics burn cleaner, need fewer antioxidant additives and provide better long-term stability than petroleum-based's that simple." I would agree that there is probably a range of "VERY GOOD-BETTER-BEST" vis'-a-vis' dino oils, but think it would really have to be a very poorly designed synthetic indeed that wasn't superior to conventional oils to begin with! Somebody would REALLY have to screw it up, bigtime! [freaknout]
Matt89 has a point. Those of use that live in the rust belt will have rotted out junk heaps before the engines die, even with manufacturers recommendations. However, I want my car to run as good as possible for as long as possible, so I will continue my "excessive maintenance" routines. [Smile]
Novadude; That's certainly your call - beats gambling away the grocery money or whatever [stretch] I didn't mean to throw a wet blanket on people's efforts at running their cars like new for as long as possible, oil analysis etc...just making sure the other side of the coin gets heard (bad mixed metaphor). Sometimes I think people are over the top about what you HAVE to do with your car or else your an auto-neglecting POS. And it usually involves spending money. On their product [Razz] Good luck. Speaking of Novas, I wish I had my mom's 1976 or 77 - it was battleship grey with red vinyl interior. Awesome!
Not open for further replies.