Has anyone actually done a study on engine life and dino vs synthetic ?

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Jan 23, 2003
Leominster, MA
I did some searches but could not find any previous posts. Wondering if anyone has done a test with a fleet of identical vehicles (maybe several different car model fleets and randomized city/hwy miles) and compared engine life when running dino vs syth. I have seen the pictures and also wear analysis. I understand the auto mfg's target a 90% survival rate at 150K miles with the OEM recommended fill. Wonder if someone could say I would go to 250K w/synthetic ? Or have prove it out with testing ? This would include all internals including oil pump etc.. I guess there would have to be some pas/fail criteria, like blow-by, oil consumption etc..
Mobil has done several tests with 7.5 K oil changes and 15K changes and after 200 K there was "almost no wear" They ran the tests with conventional oil and there was significantly more wear. That was a number of years ago. Oils have gotten better. My gut feeling is that if you change conventional oil at 4K or so-an engine will go 200K and probably have more wear than with synthetic. But it probably isn't overwhelming.

But to answer your question-You won't find this information published anywhere-other than the information I gave you.
Al - The problem with that study was that there was actually no control done using conventional oil. In other words, it was completely unscientific.

There was also the often cited Consumer Reports oil test that found no significant difference in engine wear (after tear down)in NYC taxis running the same GMC engine using any of several major brands of oil including M1. There are at least 2 problems with that study: 1) there were relatively few cold starts compared to normal automobile operation and, 2) the variation in wear between individual engines was never reported. Since the cars were driven by different people with unique driving styles (anybody who has ever spent time in NY cabs will know what I mean), it is likely that this variable would have masked smaller differences in oil performance.
Yep, amazing what can be done in a "test" situation.

Mobil used to run a series of adds to prove how wonderful their oils were.

They took a car off the shelf, ran it in, changed the oil, then drove from Sydney to Perth and back, and again, and again, etc, etc. Analysed the oil, and gave the oils a thumbs up after the right number of trips.

From these "Super Drop", 20W-50 (SF in those days) was given "20,000 km of engine protection".

Mobil 1 was given "40,000 km of engine protection".

Everything in the add was probably true. However, the test was misleading to the average public IMO.
I believe that if the mineral based lubricants were matched to the ambient temperatures throught the testing, there would be very little if any measuerable wear difference between the engines.

Typically synthetic engine oils have the advantage of being the right viscosity for the job over a broader temperature spectrum than mineral based lubricants.

Winter will be at our door steps in a couple of months in northern USA and Canada.
At the moment I have straight weight mineral oils in a few vehicles, some of which don't belong to me.
I feel that as long as day time temperatures remain high, today over 95F, and trips are long, an SAE 40 is ok to use and MAY provide better wear protection than a multi-grade engine oil whether it is a synthetic lubricant or not.

BUT....All it takes is a few cold nights, and suddenly I have the wrong viscosity of oil.

The other end of the temperature spectrum is in mid winter when the temperature is at -40C instead of +40C.
At this extreme cold, a mineral 5W20 or a very good 10W may perform just as well as a 5W30 or 0W30 synthetic.
I doubt at this cold temperature the engine oil ever properly warms up, even on the highway, to the point the engine is wanting for a thicker oil.

Now I doubt if any oil company is going to start testing this theory on private passenger vehicles and risk killing off the lucritive synthetic engine oil market.
And I doubt if any one person is going to purchase two identical vehicles with twins driving them.
And, I doubt if many people would want to change out the mineral oil 6 times throught the year to optimise the viscosity to the ambient temperature, while the vehicle using a synthetic 0W40 can use the same oil all year round.
So we are back to square one.
I'll monkey with straight weight mineral engine oils, and perhaps a 0W40, or 0W30 for a few months, while you laugh and sit there with one multi-grade synthetic all year round.
The difference is....I'm paying $2.70 CDN a litre, and you are paying through the nose.
It all boils down to how many miles you put on your vehicle, and how much you want to pay to lubricate the engine over the same service life?
If you look at this oil analysis, I think it will help show the difference between the two. Start at the beginning and see how I used a synth blend, and moved over to a mineral and how the wear actually dropped, and by the last analysis, I had moved down to a thinner oil, compared mineral against the blend again, and no measurable wear to speak of. Yes,a good quality mineral oil if not pushed beyond their designed limits will protect as well as a synth.

Not a study but my Toyota Cressida has been 245,000 with Castrol GTX every 3000 miles. It burns oil 20w-50 at 1 quart per 500 miles. No leaks at all.
Miatadon has a Miata with 215,000 miles and has used Mobil 1 every 5000 miles. His car burns less than 1 quart of 10w-30 every 3000 miles.
Seems like a reasonable assumption Mobil 1 synthetic is better than Castrol GTX.
Not a "scientific study", but Mercedes found out the difference when many of the US dealers used non-synthetic when servicing the cars. The oil monitoring device was set for use with synthetics.
Cost more than a few engines.

Possibly some in-house studies done by the OEMs, who now factory fill Mercedes, Volvo, Saab, Corvette, etc with synthetic.
Wow, that link turned out to be about 45 minutes of reading, but in the end the Amsoil guys will still use Amsoil, the red-line guys will still use Red-line and so on.
The part that interests me the most is flow VS lead content in the UOAs.
That plays into the work I've been doing with posts in the loose tolerance engine and bearing film thickness threads.
Quite often you will see people saying to move to a thicker oil to raise the oil pressure.
In truth raising the oil pressure by increasing the engine oil's viscosity lowers the flow to the bearings.
If for example the oil pressure is dropping excessivly as the engine is warmed up to the point the engine is at risk, then measures to improve the oil supply should be the first course of action.
The first place to improve oil flow, and it showed in the linked test above is by switching to an unrestrictive oil filter.
In the race pits, we call those filters "just enough to catch the rocks and birds".
The second method of increasing oil flow is to install a better oil pump, wich was a partial fix for a few German import cars that were experiencing rod bearing failures.
In every test people will read the results to suit their adjenda.
For me, as the oil thickened and filters plugged up and became restrictive the lead increased in the UOAs.
That fact, I believe is so very important in high performance and race vehicles where rod and main bearing problems from lack of lubrication are likely the most common cause of engine failure.
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