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Royal Purple vs Mobile 1

I’ve been hearing mixed reviews about which synthetic motor oil is better. Anyone have thoughts or prior experiences with one or the other? I’m trying to figure out which brand is better. Some say Mobile 1 EP, others are very adament that Royal Purple is the standard when it comes to synthetic motor oil. What’s your take on this?

I challenge anyone to produce an objective, third-party test that shows that either oil will result in any practical difference in engine life or efficiency. Changed at the proper intervals, either would be good for more than the life of the car. Of the two, I’d choose Mobil 1 based on price (the only apparent difference between the two).

Which oil is better? Neither is better. As long as you change your oil when you are supposed to, you won’t have any problems. Buy whatever makes you happy and you’ll be happy.

“the only apparent difference between the two”

What? Royal Purple is PURPLE and that obviously is an advantage over plain old brown oil!

I will have to agree. Neither one is better than the other. If your vehicle does not require synthetic oil then you are just paying extra to say “I use synthetic oil”. Does your vehicle “require” the use of synthetic oil?

It depends on what kind of vehicle it is being used in.

Each car has minimum specifications for oil used in the engine. The only way I would consider one oil superior over the other is if one meets those minimum standards and the other one doesn’t.

“Mobile” motor oil?
Does it move by itself?


I’m sorry, but I have a hard time accepting that people have driven past MOBIL gas stations for decades, but have never noticed that there is no “E” on the end of the brand name.

Anyway, as others have stated or implied, the frequency of your oil changes will probably have much more to do with the longevity of your engine than the brand or type of motor oil. Synthetics have a definite advantage in terms of consistent viscosity in extreme temperatures, but that is their only real advantage. Those who decide that they can drive their car for extended periods between oil changes with synthetic oil are not doing their engine any favors.

Buy an API-approved oil of the same viscosity and the same specification listed in your Owner’s Manual, and change the oil at least as often as listed by the car manufacturer. More frequent changes are beneficial if you do a lot of short-trip local driving.

Oil is relatively cheap, and engines are expensive. More frequent oil changes are better in the long run for your engine, as compared to extended drain intervals with synthetic oil.

My car is an older car, so while it’s not required, the good thing about synthetic oils is being able to protect and make older engines last longer.

"… the good thing about synthetic oils is being able to protect and make older engines last longer."
Please present the study that established that, because this is the first I’ve heard of it.

Yeah, conventional oil when changed regularly will do just fine. Many an engine has made it over 300k miles on a steady diet of conventional. I’ve also seen a few engines die with less than 200k using Mobil 1…When it comes to how long your engine is going to last, it is a quarter luck and three quarters maintenance, roughly. (scientific study pending)

Sorry…but that’s pure hype from the synthetic oil manufacturers. It has no basis in fact.

It’s a wash and an engine that uses regular old API certified dino oil will last just as long as an engine that uses either one of the two that you mention.

What shortens the engine lifespan is not checking the oil level on a regular basis and running them very low or out of oil or not changing it regularly.