Motor Oil Myths & FAQs – Synthetic vs Conventional

Motor Oil Myths & FAQs – Synthetic vs Conventional


Hello everyone, and welcome. In this video, we’re going to be discussing frequently asked questions and myths surrounding motor oil. Now rather than me blabbering and trying to convince you of what is true. I’m going to be asking Shanna Simmons, who is a research engineer for Shell. Who has access to the information and research needed to answer these questions. And hopefully she can put some of these myths to rest. So my first question is, “I put 5W-30 in one of my cars. What does that combination of letters and numbers mean?” Let’s discuss what a multi-grade viscosity really means. So, the 5 is the viscosity grade when it is cold. So, remember the W stands for winter. The 30 is the viscosity grade at the engine’s operating temperature. Engines operate at around 212°F (100°C). Okay, so why should I change my oil? As an engine burns fuel it deteriorates the motor oil. Changing your oil helps to remove harmful contaminates and it replenishes the additives that have been depleted. So, what is the typical composition of motor oil? So this chart shows the typical composition of motor oil. So depending on the formulation, the motor oil will be about 75-90% base oil. The other 10-25% will be additives. So the base oil determines the fundamental properties of the motor oil and the additives help to enhance the base oil, help to protect the base oil and help to protect the mechanical equipment. Ok, now you mentioned oil additives. Are aftermarket oil additives something I should be using? No! Branded products already contain carefully balanced additives for optimal performance. And I’m sure that same logic can be applied to many brands of oil out there. Now, alot of people debate about conventional and synthetic oil. Before we get into that, what is the difference between these two terms? So the base oil can either be conventional or synthetic. If the base oil is conventional it means it’s only been refined from crude oil. If it is synthetic it means it has been through an additional chemically engineered process to give it better properties for use in a motor oil. Okay, so is synthetic oil compatible with conventional oil? And can the two be mixed? Yes. Motor oil labelled a synthetic blend already contains both synthetic and conventional base oil in the formulation. We also carefully test our motor oils with other motor oils to ensure compatibility. A lot of people debate whether or not you can use synthetic oil to break in an engine. Can you? Yes. In fact, a majority of vehicles manufactured today are factory filled with synthetic oil. And many race teams also use synthetic oils to break in their engines. Now, sludge is a term often brought up when talking about engines and oil, what is sludge and what causes it? So, every time your engine is running by-products from combustion build up and contaminate the motor oil. If contaminants build up inside your engine they can set a lot and form sludge. Using low-quality motor oil, neglecting to change your oil and maintenance issues can all lead to sludge forming inside your engine. Now I often get the question, can I use this certain viscosity grade even though the manufacturer suggests another viscosity grade? Why should I use the viscosity grade that the manufacturer recommends? Your engine was designed with the specific viscosity grade in order to lubricate menchanical parts properly. If you use oil that is too thin, you may run into wear issues. If the oil is too thick, engine efficiency may decrease. Always follow your vehicle’s owners manual to determine the correct SAE viscosity grade to use inside your engine. So, a huge thank you to Shanna for helping answer some of these questions and as always if you have any questions or comments feel free to leave them below. Thanks for watching.

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  1. I guess one question I have is what is really the best motor oil out there? Some highly recommend Amsoil, others recommend Mobile 1 and others recommend Royal Purple. Are there any peer-reviewed articles pertaining to which is truly best?

  2. Only a petroleum engineer is qualified to giving advice about the finer qualities of oil. Videos done by mechanics are generally useless.

  3. Everybody knows that women can't have any idea about technical issues. How can you believe somebody who isn't able to get a small car in a parking lot?

  4. I hear all the time that older vehicles that have always used conventional oil should be kept with conventional oil. Is there any reason not to switch to synthetic on a 30 year-old car?

  5. For engine upgrades, what is more important to change once power reaches a certain level (say, for example, a 1.8ltr NB MX5 when the engine power is doubled) to maintain effectiveness? Oil viscosity or oil cooling?

  6. Hi. Does manufacturer recommended oil viscosity have anything to do with ambient temperature of the location you drive your car?

  7. with that  being said what about for older vehicles which most mechanics seem to recommend using a higher viscosity oil for that vehicle say originally a vehicle is supposed to use 5w-20 but after 150K miles the mechanic recommends using 5W-30 would that still cause an engine deficiency issue or not?

  8. Ford recommends 5w-30 (preferred as per the owner's manual) for my car but 10w-40 (A5/B5 specs) is also an acceptable grade. I live in the desert where the temperatures rise up to 50degC (120degF). Do you think it is better to use 10w-40? or I should stick with 5w-30 as it is the manufacturer's preferred choice. The temperature never dives below 15degC (60degF). I am trying to understand the relation between the ambient temperature and the engine oil grade.

  9. Love how that "Shell oil expert" reads off the piece of paper she's holding. I use Amsoil, and don't worry about a thing. Oil companies like Shell don't make a good synthetic. Their bread & butter comes from crude and don't really want you buying Synthetics, so why would they make the best synthetics they could?

  10. So it seems if you were to use additives such as Lucus, this applies to those who use cheap oil within their oil changes. Another thing that I got was to change your oil& filter more often than not.

  11. We are factory of motorcycle engine oil. If you want to wholesale , pls contact me on whatsapp +8618689280424

  12. Your almost sending people in a bad direction!!! Synthetic oil has lots of detergent to act as a dispersant . As filtration technology became better in the early 80s they started adding detergent to lock on to the particulate to make the mass of the combined material bigger so that the filter element could lock on to it and retain the contaminate removing it from the engine. Back in the day it was common practice to remove the oil pan and clean the contaminated sludge off the oil pan. Back then filtration was not that good so the used a straight weight non detergent oil so the contaminant would settle to the bottom. Now days the good stuff in oil like ZDDP aka zinc is being removed because it’s bad form the catalytic converts . This means oil company’s are more worried about O2 sensors and catalyst filters then the proper lubrication to the engine. It’s also VERY IMPORTANT to understand that detergent being a dispersant also means it will not allow the good stuff like zinc to adhere to the friction surfaces. This is why when breaking in a older flat tapped or even roller lifter engine it’s best to use a non detergent oil. By using a straight weight NON detergent oil and mixing the ZDDP zink additive to it will greatly help the break in period . To my knowledge except racing oils there are no straight viscosity synthetic oils that have low levels of detergent . To recap oil company’s and fuel company’s are more worried about emissions and mpg…than protecting engines . Honestly the 3 best oil brands you can run are… red line oil because the base oil they use is super high end and found in transformers on telephone pols used to cool. The red line oil resits burning considerably better than any thing else out there. This is very important in my line of work to combat the driver burning to death, but also is important in high performance engine with high cylinder pressures because of induced detonation due to oil getting in to the combustion chamber . Combustion technology’s aka Clean boost oil is right there with red line. The owner of clean boost was red lines head chemist for manny years. There’s also Mr Race Oil . A new company doing very great things in the high Perfromance field. I love your vids and your a smart kid. I think the older you get you will start to realize there’s a lot more out there to learn then first thought as a young man.

  13. I will tell you that Joe Gibbs driven break in oil is worth it’s weight in gold In my book. Brad Pen is also. There was a lot of nitro engines scuffing pistons on the warm up. By just switching oils to the redline nitro 70 weight all that went away. In my personal Diesel trucks I run nothing but Rotella . I have friends that run mini mod tractors with blow alky hemis that are sponsored by shell. The new race oil shell came out with is pretty unreal how good it is.

  14. ALL multi viscosity oils are a COMPROMISE regardless of type or brand………..And the wider the range, the worse the oil is due to all the additives used to try and immitate a straight weight oil………..

  15. Pennzoil is Shell with different branding for the US market. It is not considered a top tier oil here in the UK….. I will be staying with Petro- Canada Supreme Synthetic.

  16. There is no one size fits all motor oil……….As always, the type and viscosity of the oil you need to use varies wildly from one region to another and from one driver to another………The 0w-20 and 5w-20 oils stamped on the oil cap are merely CAFE compliant oils that should only be used if you live in the arctic circle……..Everybody else needs to use 5w-30 or or greater viscosities……..And those living in hot southern climates need to use a 10w-30 or 10w-40……….

  17. Red line or Clean boost oil is the absolute best. All you have to do it try to clean it. Spraying break cleaner at it is like water. Only race gas will break it down

  18. Does a diesel engine's oil break down less or none whatsoever over time due to its fuel being an oil versus gasoline is more like a solvent? Or is it due to diesels somehow having a tighter piston ring seal preventing fuel from entering crankcase and breaking down the oil. I've heard thats a major contributor to the longevity of a diesel engine. (other than lower engine operating speeds and block rigidity)

  19. If I mix 5w30 Amsoil with 5w50 Amsoil in equal amounts, will I get a 5w40 viscosity rating? No one on YouTube has addressed this issue, that I can find.

  20. OK… Now so since the first number is for winter viscosity… and since the other number is the viscosity at operating temperature, If I am doing an oil change during the summer and I know I will changing my oil soon again (long trip planned) could I use a 10w40 instead of a 5w40? They are both 40 at the running temperature…

  21. Synthetic oil was designed for people who go past regular conventional oil changes. It's recommended to change oil at 3000-5000 miles where synthetic can last about 2000 longer. Conventional oil is just as good as synthetic oil as long as your religious with your oil changes. Conventional oil has been used since the automobile and has done well since then. Keep your oil changed using conventional oil and you will not have any problems.

  22. You think l could use viscosity oils in my lawnmower? They suggested straight sae 30? Why not a thinner 5w or 10 w ?

  23. SHELL ROTELLA T6 5W-40 PROLY THE BEST TYPE 3 OIL IVE EVER USED. I PUT IT IN EVERY VEHICLE IVE OWNED FOR QUITE SOME TIME

  24. This is the most horrible editing combination ever… The guy sounds like he's in a closet and the girl footage is clearly another video the dude just recorded playing back on a screen… Both horrible.

  25. Should I ever use engine oil adaptives? “No!” Boi I’ve been using Lucas oil in my ford since day 1 and it’s been the best investment of 8 bucks I’ve ever gotten

  26. Usual Oil Additives in Europe is 10.6-13.7% and the USA has 5-7% Additives. Same oil can be of different quality in EU and USA market bc ACEA and API cant be compared directly. No International/worldwide classification exists. Here in EU we say that oil in API group III is "partly synthetic" and group IV (PAO) is ""fully synthetic" and oc group I and II is mineral oil. In the USA group III oil is often called ""fully synthetic" incorrectly.

  27. In 5W 30 , 5 is a viscosity reference at cold temp but at what temp ? 30 is actually a SAE30 again a number on viscosity chart at 212 F. When oil gets heated up usually they tend to become thin and viscosity decreases, but still we read 30 which is way more than 5 at cold condition. How will you explain that ? Viscosity is a viscosity ….whether cold condition or hot. Does it mean viscosity number chart is different for cold and hot condition ? There are so many videos where product seller is trying to show through pour test at – (minus) 10 or 20 C where the oil looks so thick and hence is must be high but yet number given is only 5. How do you explain that ? When oil gets heat up at 212 F it becomes 30 ? …..if 5 is so thick then what will be 30 ? Pls explain the logic behind it …..

  28. I switched to a 5w 40 synthetic oil in my 97 daweoo lanos without experiencing any kind of leaks will it harm my engine? (it used to run on a 20 w 50 conventional oil)

  29. And those of you trying to be as frugal as possible with your motorcycles, stop using automotive oil with friction reducing additives in your motorcycle that has a wet clutch and uses the same oil throughout.

  30. should have asked what the difference is between Advanced Full Synthetic, Full Synthetic and 100 percent full synthetic

  31. Why is the recommendation 5w20 synthetic blend in the USA but 0w30 synthetic in Europe on an exact same spec 2.0 focus? My guess is America’s outrageous fuel mileage requirements. Due to the oil difference I noticed a difference in change intervals also 1 yr or 10k in US And 1yr or 12.5 in Europe. FYI I did double check to make sure it wasn’t a km.

  32. Hello everyone, I accidentally overfilled my car with engine oil when i was doing oil change thru DIY,a half quarts less than, is it okay?

  33. So what would make my car seem to run smoother on conventional and run worse on synthetic. I have a 2011 subaru legacy 3.6r with 83k on it so it's practically just broken in. I switched to dino oil just to see how it would run and it was shockingly better. Btw I know I'll have to change it earlier than synthetic. I figure if it seems to run better shouldn't I use that from now on as long as i follow the severe maintenance schedule.

  34. Why does 5-30 fully symthetic engine oil turn red after around 2500 miles in a 1.6 litre vauxhall astra petrol engine. Vauxhall recomend fully symthetic oil In this car.

  35. Hi. My motorcycle uses semi 10w40 oil. I have in a quart a mix of liqui moly, Motul and Wolf Belgium semi synthetic on excedent from previous bottles when changing oil. Can I use this tree brand mix with identical API and JASO specs? Thanks in advance.

  36. Hey! A big issue I see with the Hondas and Acuras I service,,, I have found short trips not allowing the oil and block to reach operating temperatures allow moisture to contimate the oil leaving behind a YELLOW FILM. I would much like more information on this

  37. Hmm, so my bikes owners manual said I should put 10w40 engine oil, but I put 15w50 (fully synthetic) in. I didn't have the manual at the time. Is it a huge problem? Seems to run fine.

  38. Actually, the term "synthetic" has no legal definition when it comes to motor oil so it is all marketing hype.
    ……..
    Dino oil is being called "synthetic"
    ……
    And there is no legal definition of what percentage of mineral oil is allowed in "synthetic" oil.
    …….
    And ALL oil comes from out of the ground in some form.
    ……
    Even the holy grail of synthetics is in fact not created by man
    since it is in fact made from natural gas which came from decomposing dinosaurs and plants.
    …..
    So in the end, this is merely a way to sell the same old oil for 4
    times the price to the gullible millennials

  39. Disappointing. No questions about the best way to stop thin oil smoking above 100k & 200k. No clear ID for real synthetic.

  40. Why is she not making a sandwich? I’m not taking advice from a woman! It’s proven they have a smaller brain.

  41. On my Turbo car, I used Liqui Moly for many years, then changed to Ravenol recently. Both are same SAE 5W40. Why does the Ravenol make my engine noticeable more responsive and lighter when both are same grade ?

  42. Big question is why do mechanics recommend higher viscosity oils in high mileage engine compare to.manufactor that states to stay with same viscosity

  43. I wanted to hear answers regarding using different viscosity rating from the manufacturer depending on the type of climate one lives in, for instance extremely cold and extremely hot weather. Should one choose a lower before the W number viscosity for extremely cold winters and increase viscosity (2nd number) for really hot summers?

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