I don’t think anyone disagrees that Synthetic oil isn’t better then regular dyno oil…the question is…Is it NEEDED in your average daily driver??? In MOST cases the answer is NO.
Who said “synthetic oil doesn’t do anything?” Even if it did nothing else, it has been proven effective in draining one’s finances.
As long as you follow the owner’s manual recommendations, using the type of oil it recommends, and as long as you change it as often as the owner’s manual recommends, your vehicle will last as long as a vehicle whose owner spends extra money on synthetic oil when it isn’t recommended.
I’ve always been happy with synthetic oil and would never go back. I wouldn’t run any oil for 15,000 miles unless you routinely took samples of your oil and sent it to a lab for analysis. I’m sure the ‘normal’ filter is fine, but I would change the filter material at the recommended time/mileage regardless of how long the oil stays in. I used to do conventional oil and filter changes at 3,000 miles. When I switched to synthetic I upped it to 6,000 miles. My logic being that the synthetic does last longer, and filters are good for at least this long unless you have an engine that’s already dirty. The manual says 7,500 so I’m still beating that, and with better oil than recommended. Also, doing the oil changes half as often puts the synthetic oil change in the price range of what I was paying for conventional oil changes twice as often.
I wouldn’t run any oil for 15,000 miles unless you routinely took samples of your oil and sent it to a lab for analysis.
Changing the oil ever 5k would be cheaper then sending the oil out for analysis…Lab analysis is a waste.
That’s a very good point. I suppose for the obsessed person that has to get every mile out of their oil, sending a sample out for analysis would be a good way to get an indication of how used up it is at that mileage though. I’d rather just change it.
In a modern engine, the only real source of contamination for the oil is the oil itself. Fuel injected engines running properly have almost no “gas wash-down” and with modern air filtration, outside contaminants can’t get in.
If your engine is equipped with gapless rings, I’d agree with you but most production engines still run rings with gaps so there is always combustion blow-by.
Good point. In another post I indicated that frequent oil changes cost about $100 per year more over the life of the engine than the absolute minimum required by the manufacturer, but they make the engine last its full design life of 350,000 + miles without internal work.
However, if you own a fleet of 500 cars, oil analysis on a random basis will determine what is the most economical interval. You can afford a few premature engine failures if you are saving $25,000-$50,000 per year on reduced oil changes. An individual owner cannot take this risk. Nor can the military, for obvious reasons.
So taxi fleet drain intervals are misleading because they are economically determined as per the above process. And the driving pattern is very different from a private owner’s.
"That’s why they use conventional oil in all those race cars, right?
For pete’s sake! I do alot of driving, and I have never once seen a Toyota Sienna run at 15,000+ RPM at full power for any length of time. Minivans do NOT have racing engines in them and do not generate the range of heat that would require syn. oil unless you drive it like an absolute maniac!
The specified oil and filter change interval for all 2007 Toyotas is 6 months or 5000 miles, whichever comes first. OP, your standard filter is OK for at least 5000 miles; where did you get 3000 ???
Toyota used to have 7500 miles until the sludging occurred. Then they cut back.
Once more, fooling around with an extended drain oil, no matter how good, WILL VOID YOUR WARRANTY!!
Agree double clutch. Good racing oils are normally single grade and synthetic to withstand the incredible temperatures and bearing loads imposed on racing engines. These oils are drained at 500 miles, so THEY DO NOT NEED ANY ADDITIVES!! Racing is a different world.
Using a typical racing oil in your car in Minnesota in the winter will quickly wreck the engine!
You missed the point. Yes there is combustion blow by, but it is far cleaner than it was many years ago. It doesn’t contaminate the oil as much as it used to.
What kind of driving do you do?
For example if I had my old commute of 50 miles each way with one stop light no traffic I would not hesitate to try 12k intervals(every 6 months) with the product.
I ran a 95 Civic using bulk dino with 7500 mile oil changes(spec’ed in manual as normal) during that old commute. It was sold running perfectly at 225k miles but well worn out(seats, suspension, body creaks/rattles) with engine never opened except for one timing belt. The next owner is approaching 300k currently.
Sending oil out for analysis…is it proving anything to you??? Are you able to achieve 500k miles while I only get 350k miles?
You listed two sources of oil contamination but did not mention combustion blow by so that is why I mentioned it. It’s not the same issue as gas washdown. Of course, combustion efficiency has improved over the years but it can’t be discounted as a primary contributor to oil contamination IMO. Soot and particulates are still generated by the combustion process, albiet at a reduced level with modern fuel injection and engine management systems. This is where we differ, I think.
I was alluding to OP’s original idea of changing oil at 15,000 miles. That would get him certainly only 150,000 miles of engine life, as well as void the warranty.
I usually do one or two oil anlysis ($15) to test whether the interval makes sense; in my case it was too often and I stretched it to 4000 miles. This is standard industrial practice to determine the optimal interval. As lubrication engineers will tell you, lubes and changeouts are “operation-specific” and “site-specific”.
The car we did the test on was sold in 2004 with 320,000 miles on it, did not use oil and is still running around town without blowing blue smoke. So you might conclude that you can get 500,000 miles out of a standard engine with dino lube oil and not go broke changing oil.
I sold another small block V8 car with over 150,000 miles and it still had 100% of compression in all cylinders and did not use any oil.
The 350,000 miles I referred to in my post is what the average driver might expect from difficult driving conditions (cold weather, traffic) compared to the 150,000 miles under those conditions with bad maintenance and very long oil change intervals.
Why would Mobil sell Mobil 1 oil filters and proclaim their extended mileage oil - 15,000 miles - is good for 15,000 miles if it isn’t so? Seems there are a lot more scientists working on Mobil 1 that know a lot more about that product than someone who speaks only urban legends about synthetic lubricants. I feel sorry for the Sienna owner. Sounds like Toyota is using some of the same tricky, sneaky, tactics that made Detroit car companies so loved (not) by the American people. Could Toyota have been taken over by American marketing types? Hmmmm.
Soot and particulates go out the exhaust. Blow by, if it is significant enough superheats the surface of the oil in the pan causing gray smoke. Its not common for a new engine to allow that much blow by. Simply, blow by is not a significant contributor to oil break down, and what is does contribute is not contaminates, but heat that breaks down the oil, the oil is still the source of its own contaminants.
An oil analysis allows people like me to have an idea how the engine is doing.
I have done an oil analysis on my '07 Altima with every oil change I have done on the car since I bought it new.
I got to find out several things about the engine and the oil that Firestone was putting in my car with every change. One of the most important things was when the break in period on the car was actually over, and all the silicon that is associated with the original engine assembly is finally out of the system.
Another important thing I learned is that the oil Firestone uses (Kendall) is considerably better than the stuff that Nissan put in from the factory. I have that in writing in one of my analysis reports.
I also just bought a Porsche Boxster a couple months ago, and just did my first oil change the other day. I am sending out a sample for it to see what condition it is in internally.
Mainly, I would rather know ahead of time that something is going wrong with the motor, and what it might be, instead of assuming everything is fine, and being blind sided one day by an engine failure.
Also, I know for a fact that you can go between 7500 and 10k miles on Kendall 5W30 Semi Synthetic oil in an '07 Nissan Altima. My last oil change was with Kendall Full Synthetic, and I’m curious to see if its any better than the Semi-Synthetic.
BC.
Bladecutter; it’s nice to learn that you are being methodical about optimizing your oil changes.
As per a previous post, your oil change interval will largely be a function of your driving pattern. Any driving pattern where the engine thoroughly warms up and spends little time idling will allow you to stretch your oil drain interval. Since you analyze your oil, and are going for 7500 miles, your driving must fit into the “easy” category.
I used semi-synthetic when living in a very cold area, it allowed easy starts and low engine wear in cold weather, but I did not extend the drain interval(4000 miles) because it was semi-synthetic. You will likely find that full synthetic will give very similar results to semi-synthetic. However, if your new Boxter is turbo-charged, you will likely need a full synthetic meeting Porsche’s specifications.
Car manufacturers have no idea how an owner is going to use the car, so they should err on the safe side with oil change intervals, by stressing “severe” driving intervals. In reality, nearly all US driving fits closely to the severe category; mostly city/commuting with many cold starts. This is the main reason why we see so many lubrication-related engine problems.