I assume that the quality of the resulting oil is pretty much the same no matter the source. Aren’t the resulting molecules pretty much the same? Is it just a different source oil and different process to get the same final result?
@cwatkin I wouldn’t be surprised although there are some who disagree with that.
The molecules of a synthetic base stock such as PAO are all the same size and shape, which gives it that great thermal stability and very high viscosity index. That’s a major chemical change.
Dino oils, as pointed out are refined from crude oil and still have a wide range of molecule shapes. Hydro-treated base stock (such as produced by Petro Canada) is somewhere in between, and is a great improvement in viscosity stability over dino.
While I don’t know how this applies to Wal-Mart oils, I do know that they tend to spec that vendors sell products to them at a much lower price. I would post the link but they always get knocked out as SPAM when I do. Look up Wal-Mart Snapper Mower Fastcompany on Google and you will get a really good example of this as it applies to mowers. I can personally tell you that their computers and other electronics are the same way. Most even have a model number that corresponds to being sold at Wal-Mart between a certain set of dates. These are much lesser models and I always seem to get them in right after the warranty expires. I know some people have good luck with them but I see lots and lots of duds. You would be less frustrated dropping $300 down the toilet than buying one of these pieces of junk.
I have read the same about the film strength of true synthetic oils. I personally use the Rotella T6 5W40 in non-emissions equipment and the Mobil 1 0W40 in most others calling for 5W30 or close. I have always been told that the 40W spec on this is a very think 40W when warmed up so not really a concern over a 30W. Now if it was a 5W50, I wouldn’t want to go that far. Yes, I have seen a Castrol 5W50 as that is what my air compressor calls for.
Anyway, it may be overkill but it is peace of mind for me to use synthetics.
Some need to come on down to Springdale/Rogers AR. Purchasing listens to manufacturers “offers”. Wally World has ZERO experts. They rely on the fact the manufacturer wants repeat business. It’s a purchasing department - nothing technical about it.
Yes, and the vendors to WM are encouraged to sell at a low price. I don’t think technical specs or quality are much of the equation. That being said, it is a lot harder to sell lower grade oil that might void car warranties than sell a cheaper version of a Sony TV or HP computer which might break sooner but not do any other harm unless it is a safety hazard and catches fire.
I am curious and am sure someone somewhere has done this experiment. Lets say a car is filled with a fresh change of oil and just driven continually. They refill the gas and just keep driving. A new driver switches out every 8 hours or so but the car is never off more than a few minutes and can never cool down. How would the oil look in a car like this? I would assume it would potentially last A LOT longer than oil in cars that are driven normally. This also assumes that the engine is in good shape without excess blowby and such.
This would basically eliminate rich running during warmup and condensation from water vapor. Anyone ever done this? I assume engine and oil life would be greatly enhanced.
@cwatkin
Actually, I think the oil would eventually be in terrible shape
I seem to recall Land Rover did a similar experiment, and they soon realized that the oil was worthless after awhile. I believe it was a publicity stunt. They had promised to not change the oil at all. They did add oil, due to sludge and consumption
I for one, would NOT want to be the next owner of such a vehicle
I wasn’t meaning to run the car like 50k or something without a change. I was thinking if you normally needed to change after 5k, it might go to 10k or even 15k being driven this way with no problems. It would be interesting to take a sample for testing every so often and see how the oil is holding up. I have never sent oils off to a lab for testing and don’t know what volume is required. This could end up impacting the test of 1/2 quart or so needs to be replaced during such a test.
I know someone who bragged he had no changed the oil in his large motorhome for about 40,000 miles, just topped it up when needed. As said, I would not want to buy such a vehicle.
Many fleet vehicles such as taxis run all the time, and they tend to optimize oil change intervals at 25,000 miles or so to get the best value. They still get 500,000 miles or more out of their engines. I rode in a Cadillac V8 cab some time back and it had 650,000 miles on it and the engine was still sound.
However, to answer your question the “run it into ground” scenario depends on the quality of the oil and the size of the filter. Most say that 65,000 miles is tops for not changing dino oil; at that time the engine will be sludged up and may seize up.
While even modern engines run rich when cold, it’s far more controlled than the old carbed engines and contains far less excess fuel. In addition, today’s engines are built tighter than engines used to be, so blowby is less. These two things mean that there’s less dilution of the oil from unburned hydrocarbons while warming up.
Moisture in the crankcase, a normal byproduct of the combustion process that gets to the crankcase via blowby, is also less… since blowby is less… but it also readily and quickly becomes purged from the crankcase via the Positive Crankcase Ventilation (PVC) system as soon as pressure in the crankcase begins to elevate and the air in the crankcase begins to warm, increasing its ability to carry moisture.
In short, I don’t believe what you propose would have any significant effect on the long term life of the engine. Perhaps a very small effect, but not nothing that would be outside the normal statistical variation. In short, you’d have to run an incomprehensible number of sample engines to identify the difference. If ever.
Everybody is discussing synthetics and what extends engine life… but nobody has talked about the filtering of all those little pieces of stuff that is the sand on the sandpaper. As important as the oil is, a filter that traps smaller particles (which requires a higher capacity filter)… Soooo, I use Mobil1 5-30 extended with the Bosch distance plus and a 10,000 OCI… That lasts me about a year. It filters more and smaller particles and is well within the 15,000mi of the synthetic oil. Whaddya think about that?? J
"Running a car into the ground"
I can’t say that it happens everywhere, but around here, more cars loose their inspection stickers and are junked for a variety of reasons that has nothing to do with failed motors then the other way around. Generally, around here, it’s impossible to do…nearly. Oil changes seem to be the least of their worries when running cars into the ground, for my kids. ( they got my hand me downs) It was replacing power windows and air conditioners and rust while their motors still purred.
Motor oil changing is over rated, over discussed and generally just relegated to…do what the manual says and move on.
I would ask what particle size begins to affect the life of the engine. Without that knowledge, it’s hard to assess the impact of the differing micron ratings of filters. Your post does, however, point out the importance of changing the filter when doing oil changes.
Re: extended miles between oil changes because of the use of synthetic, I’ve never been an advocate of this because synthetic is just as susceptible to contamination and to dilution by blowby. The purpose of oil changes is to make the engine last longer, not to make the oil last longer. I do recognize, however, that synthetic is less susceptible to heat damage.
The argument has been excellently made in the past that some of us change our oil much more frequently than is necessary anyway. I’ve never seen any comprehensive study that correlates overly frequent oil changes with engine longevity, only ones that correlate the (almost) total lack of oil changes with premature engine failure of a catastrophic nature. Coking, sludging, gumping up, failure of the oil to provide the proper pressurized fluid barrier for the bearings because it was basically gump, that sort of stuff. I acknowledge that 10,000 miles using synthetic might not adversely affect the engine long term… but personally, I’ve never been much of a risk taker. I’d rather change it at least as often as the manufacturer recommends, but not beyond 5,000 miles, a personal choice not based on science but rather on insecurity.
I for one hardly ever practice what I preach when it comes to oil changes . It’s a fetish that is really hard to let go of. I do use synthetic in one car and though I really want to believe that 10k is OK, when I approach 7500 this time around, I will fold and change it. It took me a while to feel ok about “not” changing the long lire coolant till very late in my last car’s life. But then, I never had a fetish about coolant. I do transmission, differential and motor oil…l.but I am working on it. I change out the clevis pins that hold the masts up on my sailboats too often too. Besides, legitimate fetishes like changing the oil was always a real convenient way of looking busy between golf matches.
I think a disabled sail boat in the middle of the lake is a lot more dangerous than a blown engine on land. I usually change at 5K but on the last oil change we were traveling and ran it to 6K. I did notice that once the OLM hit 50%, it went downhill a lot faster. Not a linear calculation I guess even doing all highway miles hour after hour.
Fortunately, engines rarely fail suddenly due to lack of oil changes. But if one did and I were in Boston, Chicago, Miami, LA, or NYC… I’d rather have my sailboat motor fail in the middle of the Pacific… especially if I had sails. It’d be a less painful way to die.
The first time I went past 3500 Miles was in the Honda CRV I had brand new, had OLM and I still changed it at 5K b/c it had been a year from manufacturing date. On my current Mazda, since I put in synthetic I will go 5K and this would be a first.
So…what about when the manufacturer tells you 10,000 miles???
I certainly cannot fault the owner for following the 10,000 mile recommendation, but I personally would change it every 5,000 miles. I’m uncomfortable with 10,000 mile recommendations and suspect they’re more oriented toward a low “carbon footprint” than by what’ll enable the engine to stay healthy well into its old age.
So, this is a new Toyota Avalon Hybrid for which they recommend 10k oil (even with severe service). I had already more or less decided to go with 5k intervals, unless I was convinced otherwise here. I am going to have to do my first change at either 4k or 6k due to a trip.
The 4k was “new car” time. The next 5k or so is going to be winter driving with a lot of cold short trips. I am thinking I should do it later in order to take out some of the cold weather driving (assuming the following change would be at 10k). Any opinions?