FYI Synthetic VS Organic motor oil

I read on here that there is no “real benefits” to using 100% synthetic oil. That is simple not true. What I’m about to state are not my options but facts. 100% Synthetic oil last up to 20,000 mile. The problem here is that most if not all oil filters are designed for way less mileage. Solution to using 100% synthetic oil with an oil filer designed to be used with organic oil is to change the filter as you would normally do using organic motor oil. Viscosity is the same in organic oil and synthetic oil (apples to apples). If you have leaks, it’s not due to using one or the other. You can us both oils in old cars and new cars provded that it meets the oil specs for your year of car. You can switch from one type to the other when ever you want regardless of the milage on your engine and no harm will come to your engine.
Synthetic oil in general is a much better oil with long lasting (properties) viscosity and way better detergents and chemicals added in the oil with no harm to your engine. Anybody disputing what I have said, is without a doubt mistaken,misinformed, or just looking to be right about something they are wrong about here.

In closing:
I hope this will put most of the ppl who are looking for the correct answers on the right path of using what is right for them.
I have been manufacturing synthetic motor oil for year and have a PHD in chemistry. I dont sell oil or get paid for doing this type of stuff.
I’m simple doing this to give ppl truthfully facts and to let you make your own mind up what’s best for you living your life style.
Thank you and best of luck

While you are correct that you can (theoretically) go longer miles, you’re ignoring the manufacturer’s stated change interval. If under warranty, you’ll void it. If not under warranty, I’d only do this with the Mobil1 ‘long change interval’ oil. That way you’re covered by their warranty, such as it is. Or just stick to the manufacturer’s recommended change interval.

@mechanic12 You are partially right. While synthetic oils are more stable and deteriorate less under high temperatures, the additive package, which can be about 25% of the total is usually not significantly different from that in regular mineral oils.

The manufacturers of engines therefore are very cautious in specifying oil change intervals. Synthetic oils are just as much subject to sludge formation, and other forms of contamination caused by the combustion process. This is the type of contaminant not removed by the oil filter.

Synthetic oils really shine in maintaining their stability and design viscosity. Mobil1 is a great oil, but in European cars you have to a use Mobil1 Extended Drain oil which has a much higher additive package to get to that 20,000 mile drain interval specified by many European manufacturers.

If you, as a mechanic, recommend a 20,000 mile drain interval, with a special oil filter, in the US, you are not doing your customers a favor. City winter driving in Northern cities such as Minneapolis will cause significant sludging by 20,000 miles and have oil dilution of gasoline and water as well. If you don’t believe me try it for yourself and then test the oil in a lab.

This forum has had many oil posts and although you make some good points, the truth is that 20,000 mile oil changes with most US spec oils only work in constant highway driving at moderate speeds without causing excessive engine wear.

@mechanic…I think you’re misread many of the posts here about synthetic oil.

I don’t know of any post that says synthetic oil is NOT better then dyno oil. Can you post them. I’d like to see what I missed.

The people who I know who say synthetic oil is a waste…NEVER said synthetic oil isn’t better…it’s just that they see no need. There are people in this forum who have owned many vehicles with well over 300k miles using strictly dyno oil. The rest of the car is falling apart before the engine is. So it’s kind of a waste to use synthetic.

I personally use synthetic oil…but mainly because of the very cold winters here in NH and because I do a lot of towing during the summer. My wifes cars I use regular dyno oil. Last I knew her 96 Accord was well over 400k miles. Her 87 Accord was junked by it’s owner after it reached 500k miles. So tell me the benefit again of synthetic oil??

As for the 20k oil change interval. I suggest you don’t do that while under warranty. Manufacturers don’t make a distinction between dyno and synthetic.

I don’t think the full-flow oil filters used on most car engines do much other than remove any big lumps that have somehow found their way inside the engine…If your engine is shedding any meaningful amount of “metal particles” synthetic oil isn’t going to make much difference…A plugged up oil filter is a very rare thing simply because in a healthy engine there is nothing in the oil to plug it up…

Cars do not go to the scrap yard because their engines failed. Today, the engine is the longest lasting part of the car! RUST and transmission failure and the growing number of unfixable electronic problems are what sends cars to the scrapper today…

“I have been manufacturing synthetic motor oil for year and have a PHD in chemistry. I don’t sell oil or get paid for doing this type of stuff.”

I have been a mechanic for 40+ years and I will agree with you that, at least, in theory synthetic oil is better than dino oil. I believe that you are doing a disservice to many people who will buy your opinion that synthetic oil will last up to 20K. Even with the changing of oil filters…leaving any oil, synthetic or otherwise, in the crankcase of an engine for that length of time is bordering on lunacy.

I have never used synthetic and I never will since I live in a temperate zone. If I ever buy a vehicle that requires synthetic then I will use it. To paraphrase @MikeInNH…I know that synthetic is a waste of money if you don’t need it. That’s a fact. Thank you and the best of luck pushing your agenda.

Another reason to be very cautious when buying a used car with people thinking they can go 20,000 miles on an oil change. I use synthetic for the car that takes 0-20 but still change at 5000. I use dino on the others and change at 3,000. It just drives me nuts that people think the best benefit of synthetic is you can put it in and forget about oil changes. Penney wise and pound foolish, but we’ve been down this road before.

Several rifles and shotguns were cleaned and coated with 10W30 Mobil 1 oil and left in a storage cabinet. After 2 years they were pulled out to inspect and clean and the actions were gummed up with a shellac like coating. So even the top of the line synthetic will apparently gum up an engine and cause the rings and lifters to stick if left long enough. My opinion that it is worthwhile to start an engine somewhat regularly and change the oil after an extended time regardless of miles seems substantiated.

True statement.

I used synthetic oil(Mobil 1) my turbo Subaru legacy with 170k on original turbo/engine and at around 45k found it sipped a bit in my short 4k OCI making me need to top it off. So I stick with dino oil and no consumption. Maybe a fluke.

One of our regular poster stated it very succinctly: “I’m interested in maximizing ENGINE LIFE, not oil life”.

Mechanic12 seems unfamiliar with the various driving styles and patterns and the effect of climate. Yes, a long distance limousine and inter-city delivery vehicle will go 20,000 miles on a good oil, mainly because it is the ideal operating environment.

One of our posters lives in Mexico and Texas and drives a Toyota Sienna. He actually had his oil analysed and settled on 8000 miles between oil and filter changes for optimal engine life. He would not dream of stretching that to 20,000 miles.

I agree with your point about synthetics having better properties and so on.
However, there’s a lot of things that influence the condition of the oil which you have failed to address; either deliberately or through sheer lack of knowledge about what’s really going on under the hood.
Apparently you’re not familiar with oil sludging and oil coking which has caused the death of man an engine and/or turbocharger.

Factors influencing an oil change can be humidity, dust in the air, state of tune of the engine, condition of the crankcase ventilation system, and the driving habits of the car owner.

Unless you’re corner cutting for an internet post, your grammarin’ is a bit shaky for someone with a PhD (Not PHD) in Chemistry.

Is a Rolex better than a Timex? Will a Rolex outlast a Timex? Do I need a Rolex to make sure I am never late to important appointments?

“I have been manufacturing synthetic oil for year and have a PHD in chemistry”. Dude, you must have one hell of a kitchen set up to pull that one off. “I don’t sell oil or get paid for doing this type of stuff”. Your lousy writing skills notwithstanding, making synthetic oil isn’t something a fella would do in his basement as a hobby. It seems to me that it would be a muti-million dollar project to set up for such an operation. What the hell is the point if you don’t sell it or get paid for it?

Anyone who manufactures his own motor oil as a hobby has way, way, too much time on his hands…The major oil companies have buildings full of guys with PHD’s in chemistry with unlimited resources to work with…I’ve owned MANY cars and NONE of them EVER suffered a failed engine…I change my oil every 4-5 thousand miles with whatever Wally World has on sale…I can change my own oil in 20 minutes, I don’t need to switch to some magic oil that claims 20K oil changes…There is a special forum for oil fanatics, See if you can convince THOSE guys…

@Docknick: One of our posters lives in Mexico and Texas and drives a Toyota Sienna. He actually had his oil analysed and settled on 8000 miles between oil and filter changes for optimal engine life. He would not dream of stretching that to 20,000 miles - See more at:

Guilty as charged. That was using Mobil-1 EP. There was still some use left at 8800 miles. I estimated at the rate it had deteriorated, it would have nicely gone 10,000 miles with acid resistance; etc. But, certainly not twice that. I change at around 8,000 to leave a safety factor.

And, that was with my mostly long distance driving outside the snow zone. And, a high mileage motor still in really good condition. Different driving patterns will produce different results. You need to test YOUR car under YOUR driving conditions to know what is happening.

Based on the oil test, I do not think changing dino oil every 3,000 miles would give any advantage whatsoever, except maybe some sort of emotional boost. Of course, I think changing dino oil every 3,000 miles would do as well as the Mobil-1 EP every 8,000 miles.

My suspicion is OP is probably a chemist who works for a large company which does produce synthetic oil. I have a 45 year old daughter with her Master’s Degree in Science Education, and she is dyslexic. She could be a good teacher and once was, until the administrators started telling the teachers exactly what to teach, instead of letting them use their natural skills. But, guess who gets blamed if the kids don’t learn well.

Someone commented on sludging. I did a lot of Internet digging on synthetic some time ago when the topic came up. Virtually every page I found said the first solution to sludging engines is to use synthetic oil.

I have no reason to use a synthetic oil. The conditions I drive under don’t warrant the extra cost of a synthetic oil.

My vehicles don’t have a turbo-charger, I don’t race the vehicles, I don’t do heavy towing/hauling with the vehicles, and the temperature extremes I’m faced with aren’t severe enough to warrant a synthetic oil.

Change the engine oil every 20,000 with synthetic oil? Not in my vehicles! I get 250-300K miles out of my vehicles using regular oil along with regular oil/filter changes. And this is done every 5,000 miles. The only reason I get rid of my vehicles is because their so rusted out that I deem them unsafe in the event of an accident. But the engines/transmissions still run perfectly.

Did you know that most oil filters sold today are by-pass type oil filters? This means not all the oil passes thru the filter media. Some of it by-passes the filter media thru a by-pass valve in the filter. So whether you use regular oil or synthetic oil it’s not 100% filtered.

And finally, oil contamination. Synthetic oil isn’t going to help if there’s coolant leak or fuel leak into the oil. Be it from a leaking head gasket or a faulty fuel pressure regulator. Once that oil is contaminated it must be removed and changed along with the filter. And when that happens, I like to keep my costs to a minimum getting the vehicle back on the road.

Synthetic oil is great in some applications. But not in all applications.


Except for turbocharge cars that require synthetic oil, I think the best application is a high mileage fleet that can reduce staff by changing oil half as often. Taxicabs and government motor pools fit the description IMO.

“You can us both oils in old cars…”
“I have been manufacturing synthetic motor oil for year and have a PHD in chemistry”
“You can switch from one type to the other when ever you want regardless of the milage on your engine…”
“I’m simple doing this to give ppl truthfully facts”.

Obviously, someone had to re-write your PhD dissertation.

Although my memory, like my good looks, have faded in recent years I recall that early on there were 2 methods to process synthetic oil. One method’s production caused seals to swell and the other method’s caused seals to shrink but someone had the brainstorm to combine the 2 and found the resulting mixture had no effect on the seals… VIOLA(sic)… Marketable synthetic oil.

Troll Alert, the OP has never responded. I have not done the calculations for extended oil change cost benefit of synthetic compared to regular, but I am so old we used to believe it is not the oil that fails but the particulate matter in the oil that accumulates necessitating oil changes.