Motor Oil Myths & FAQs - Synthetic vs Conventional

Choosing the best, whether synthetic or conventional, engine oil is highly controversial and debated. Motor oil is surrounded with myths and questions. Shell helps answer the following:
- What does 5W-30 mean?
- Why should I change my oil?
- What is the typical composition of motor oil?
- Are aftermarket oil additives needed?
- What does synthetic oil mean?
- Can you mix synthetic with conventional oil?
- Can synthetic be used to break in an engine?
- What causes sludge?
- Why should I use the viscosity grade that the manufacturer recommends?

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[foguandme]

Conventional vs synthetic

Conventional: Refined crude oil
Synthetic: Highly refined crude oil
True Synthetic oil: PAO base motor oil created in lab

The US Supreme Court's (Mobil 1 vs Castrol) stated that "Synthetic Motor oil is nothing more then a marking term". Castrol won the lawsuit against Mobil 1.

For years Mobil 1 was selling PAO base oil (true synthetic oil) as synthetic. Castrol decided to jump into the game and sold conventional oil as synthetic.

Castrol raised the price of the conventional oil significantly to maximize profits while still less over all price then Mobil 1's PAO based motor oil.

Mobil 1 couldn't compete and sued Castrol for fall advertising. Castrol had lobbied Congress for years and ultimately won after a ruling that "synthetic motor oil is nothing more then a marketing term".

The US doesn't have a "Synthetic moor oil grade". Which ultimately means ANY company that sells motor oil can legally label it as synthetic. If I sold a 5 quart jug of oil for $1.50 at Walmart I could legally call it synthetic.

However since the US doesn't regulate synthetic motor oil their is a company that does APi "American Petroleum Institute".

The grades are
Group 1: Crude oil
Group 2: Refined crude oil
Group 3: Highly refined crude oil
Group 4: PAO based oil "true synthetic motor oil"
Group 5: GTL "gas to liquid" and all over types

Groups 1-3 all start off as the very same thing. They are all crude oil, the same oil thats used to make gas is used to make conventional AND "synthetic".

Since Group 3 oil is cheap all major motor oil manufacturers sell Group 3 as Synthetic. While Group 3 is of a higher grade then Group 2 the quality difference is marginal at best since there is no way to remove all the impurity's from crude oil. On an atomic level Group 3 oils are unstable and deteriorate significantly faster then Group 4 PAO " true synthetic oils".

Group 4 PAO oils cost significantly more to manufacturer and are far better quality then Group 3. Since Group 4 oils are manufacturerd in labs they have 0 impurity's which means they are far more stable and capable of running much longer at much higher temperatures with out the risk of deteriorating.

They also significantly reduce the risk of sludge since they are pure oils to begin with.

Group 3 are refined to remove (what they can) that are bad for engine.
Group 4 is pure so you do not have to worry about contamination since you only add to the oil what you want in it at 100% pure state.

Mobil 1 vs Castrol (source).

[mandablyatskayapizdo]

It was like reading a label on a bottle of motor oil.

[TautologyTechSystems]

Maybe I'm crazy, but I think they could be related. Or maybe it's just him in a wig?

[junoguten]

Ooooh, she's giving us the sales stare over at 1:50 .

[darrenberkey]

I didn't see any myths presented here, just general questions. Good answers, at least.

[piccolo]

I was actually hoping for a little more in depth review of different grades of oil and how API and SN standards were made.

[starrtile]

Always leaves me skeptical when there is sponsorship

[Kenichi_one]

all these keyboard warriors using Google to try and prove the girl wrong. Yeah I think I'll believe the person with the Engineering Degree

[Fsilone]

This video brought to you by Shell Oil Company. Not Just Oil, Pennzoil™

[japatel]

I am a Chemical Engineer and I worked at a major oil companiy's R&D lab for 30+ years. Of these almost 10+ years were in the Lubricant Research with primary expertise in base oils. As far my experience goes, the only advantage synthetic base oil (Poly Alpha Olefin - commonly referred to as PAO) has is its' low temperature properties. So, if you are living in extremely low temperature regions like in Alaska you need to use synthetic oil. The detergent package and viscosity index improving components are exactly the same in conventional oils or synthetic oils or synthetic blend oils.
I only use conventional oil in my luxury cars.

[JoeOvercoat]

I put one bottle of Rislone oil additive in my baby Benz and that quieted it right up, where no amount of oil changes would quite do the trick. So yes, consider additives for high mileage vehicles.

[MrSlowestD]

Not tryin to be a dick, but I feel like she read the answers off cards, and I expected a bit better explanation from an engineer/researcher.  I thought the question about whether synthetics can leak more opposed to a conventional oil (the idea being because synthetic particles are smaller, they can weep easier) would definitely be on there as a myth or not.  Oh well.

Also, I disagree with her last answer, it's not all about 'what the engine was designed for' - 8 times out of 10 it is, but politics plays a role in engineering so sometimes it's not.  In some places you have manus using 0w20 in engines originally designed for 10w30 because of fuel economy requirements or other BS.

[lowerd]

Wish you would have asked about oil change intervals. Why do some car manufacturers say 3k, 5k and even 10k miles with the same oil?

[Aeonheart]

The questions you asked were poor! And the answers were the very basics of the basics since the questions were about the basics. 

Myths like "Will changing from a conventional oil to a fully synthetic increase the chances of oil leakage?"
Or FAQs like "Approximately how much does an engine load need to be increased on daily use for the engine to require higher viscosity oil?" 

Those were just examples but there are many other, better, questions which you can't really find an answer for without talking to the experts.  Expected more detail since these answers would have been easy to find from the web, but thank you for this video anyways. . 

[CodyKing]

A normal video with explanations from you would have been just fine.

[gavnonadoroge]

maybe she can do a review of different lubes

[therealb]

I kinda like her, the way she talks, the video quality, just makes it look EE accidentally interviewed a research engineer from the past like 90s!.

[johnabbott]

One thing not mentioned, when a mineral (conventional) oil is repeatedly heated and cooled, it will eventually lose its different viscosities, ie instead of 5w/30, it will degrade to say 15 or 20. A synthetic oil will always maintain the different temperature viscosities.

[ImportTunerRB]

There's so many things missing and wrong with this video. 
1. There are different grades of base stock ranging currently from 1-5.  1 being the most garbage poorly refined cheap crap you can buy from walmart, 2 being your average conventional, 3 being cracked conventional oil and what most people refer to as synthetic(even though it isn't truly synthetic by definition of the word since it's still sourced from dino oil) grade 4 being your first truly synthetically produced (amsoil) and grade 5 being an even better synthetic base stock (redline).

2. 5w-30 does not mean its a 5 weight when cold and a 30 weight when warm.  That means it will thin out no less than a straight 30 weight oil when at operating temp (remember oil is thicker when cold) and will thicken up no more than a straight 5 weight oil when cold.  It is NOT magically a thin 5 weight when cold and then a thicker 30 weight when warm.

3.When a manufacturer builds an engine with a certain viscosity in mind they set tolerances inside the engine to match the oil.  First and foremost bearing clearances, a light weight oil will squish out easier and will run a smaller clearance to compensate, whereas a thicker oil wont flow easy enough into a small clearance and will require a bigger one.  Also the valve seals are meant to let a specified amount of oil passed to lubricate the guides.  If you go too thick you're starving them of oil, too thin and you're burning too much off(which is bad for emissions). 

Also on a side note having slightly larger clearances and thicker oil is much better in terms of performance and durability in a high powered engine.  Thicker weight oil also handles heat much better than its thinner counterpart.  The down side a minute drop in efficiency since the pump and crank have to spin through a heavier oil.  I say minute since going from a 10w40 to a 0w20 only nets a very minimal increase in fuel mileage.

[WarriorsPhoto]

Very good video. Glad you brought someone on to help answer the questions.