Synthetic vs. Petroleum-based oil?

Which is better?

There are at least 30-40 threads on this subject in this forum. The search key is your friend.

Agree, but synthetic oil is ALSO petroleum-based! The molecules are just more uniform, making the oil more slippery and more stable.

Synthetic is better or Wal-mart would not sell it.

Absolutely right. Wal-mart sells a lot of stuff that most people don’t need.

Maybe so, but slogging through just the first 100 posts didn’t reveal anything related to my concern. Care to weigh in?

There is a special place for people to obsess about Motor Oil. Here, Motor Oil is taken to a completely different level. The fun starts with German Castrol and it goes up, way up, from there…

Keep in mind that anything petroleum-based will degrade latex.

Just use what your manual recommends in spec, type, and grade. Also more most important is to change it in timely fashion for your driving type. Lastly check and top it occasionally.

If you do all those steps you likely will never wear your engine out in your ownership period.

I obsess, but not about motor oil; I’m trying to settle a husband/wife dispute, so I need the most accurate information.

Thanks for the link–I have a feeling I’ll find a solid answer there.

Thanks for the link–I have a feeling I’ll find a solid answer there.

As Caddyman noted, motor oil is taken to a completely different level on that site. It’s easy for a novice to lose perspective.

In a nutshell; synthetics excel under severe conditions, such as EXTREME HEAT, EXTREME COLD, high loads and some engines, such a s many European and turbo equipped, HAVE to have synthetic.

Synthetices DO NOT extend your drain interval; that’s a function mostly of the additive package, which is about the same for both types.

So, if your driving is normal, and you live in a climate without severe conditions, and you don’t drive a car that needs synthetic, you are wasting money.

The secret to long engine life in an ordinary car is changing oil more frequently that the manual calls for, as many of our poster haves demonstrated.

Changing “dino” oil at 3000-5000 miles will make most engines outlast the rest of the car, while using synthetic and draining it at 10,000 miles or more will likely limit it to 200,000 miles at most, while incurring twice the expense.

I could give you a detailed chemical analysis, but I’m sure that’s not what you’re after. So forget any long life claims from expensive oil sellers who sell 15,000 drain intervals. Things are different in Europe; the oil spec is very different there, and most oils HAVE to be synthetic to meet the requirements.

P.S. Your one line question does not reveal what your “concern” is. Please explain, and we can help you.

What Does It Say In The Mazda Protege Owner’s Manual About Recommended Motor Oil ?

My Owner’s Manual
Inside my car’s Owner’s Manual the manufacturer says that “SAE 5W-30 is best for your vehicle.” They go on to say that if the temperature stays above zero F degrees and 5W-30 is not available then it’s acceptable to use 10W-30.

I change oil and filter every 5,000 miles. When my car’s odometer ends with 0000 or 5000 I change the oil.

Why do I run synthetic oil in this car ?
I use synthetic oil because it handles temperature extremes better. This same Owner’s manual goes on to say that, “If you live in an area of extreme cold, where the temperature falls below -20F it is recommended that you use either an SAE 5W-30 synthetic oil or an SAE 0W-30 oil. Both will provide easier cold starting and better protection for your engine in extremely low temperatures.”

Going By The Book
Several times every winter our morning temperatures dip below -20F and many times the temperatures are near that. Rather than trying to time oil changes or remember to switch from 5W-30 to 0W-30 and then back again, I run SAE 5W-30 synthetic oil every day of the year.

I wonder about those -15F mornings and those -10F mornings, too. If synthetic is better below -20F then what about at zero ?

On those cold mornings, ?You’ve got to ask yourself one question: ‘Do I feel lucky?’ Well, do ya punk??


Here are the details:

I recently read in a “green living” book about asking for synthetic oil when you get an oil change on your car.

The book said synthetic oil (versus petroleum-based oil) lasts 8 times longer than a traditional oil. Does that mean you can go 24,000 miles before the next oil change?

Therefore (if this is true) you save money and it’s better for the environment.

However my husband counters that petroleum oils can be recycled and reused whereas synthetics can’t. He also believes that synthetics are made out of plastic-type polymer and therefore they are not “organic” matter whereas petroleum is.

The book said synthetic oil (versus petroleum-based oil) lasts 8 times
longer than a traditional oil. Does that mean you can go 24,000 miles
before the next oil change?

If your owners manual says the oil should be changed every 5000 miles, and you go beyond that because you believe synthetic allows you to, then you just gave the manufacturer a solid reason to void your warranty.

It would be very risk to leave any oil in a car for 24,000 miles.

If you’re goal is to find out which cost less money for maintenance and long engine life, dyno wins hands-down. Just follow the owner’s maintenance schedule.

As Docnick said, there are extreme situations where synthetic is beneficial. Also, some vehicles require synthetic. In those cases you have no choice.

Excuse me pleasedodgevan2, but the fact that Walmart sells synthetic oil only means selling synthetic oil is profitable. Any other information you gleam from the fact that it occupies shelf space at Walmart is only an assumption.

Whether or not synthetic oil is better depends on the engine it is used in. Some cars can benefit from it, and some cars can’t. For many cars, synthetic oil is a waste of money, but it makes the owners feel better about babying their cars.

Most of the cars out there that use regular oil will never suffer an oil-related failure, that is as long as the oil gets changed on time.

Thanks for the detailed answer. What is dyno?

The only oil related failure I have EVER seen was when:

  1. There was no oil in the engine or it was allowed to get more than 2 quarts low.
  2. The oil had not be changed over an extended period of time…

I have seen MANY more engines suffer premature wear and failure caused by:

  1. No air filter, incorrect air filter, torn air filter, leaky air-filter box/housing.

Oil wackos can PROVE synthetic is “better” by testing it under conditions THAT DO NOT EXIST IN REAL-WORLD OPERATING PARAMETERS…

He meant “dino” which is short for dinosaur (regular non synthetic oil)