Engine oil 'Explained' & Engine Oil Viscosity 'Explained'. (by Craig Kirkman)

[@johnfranklin5277]

You are a very good teacher, easy to understand you. I have been driving 45 years. Most of the time I've used 10 30, or 10 40 in my cars. I've put over 340.000 miles on several of them, all bought brand new, with no engine issues. I purchased another new car in 2017. Its got the 5 20 oil deal on the cap. When I got home after driving about 20 miles from the dealer, I opened the hood to hear it run. It sounded TERRIBLE!! I've never had an engine sound so bad. Even my old high mileage engines sounded good. I'm in Southern California and it was purchased in june and already having 90 deg f heat. So, after 400 miles I dumped the 5 20 junk, and put 5 30 in. WOW, the engine quieted right down. I run 5 30 November to June, then in june I run 10 30. We have summer temps average 110 to 125! Car has 73.000 miles now, and purrs like a kitten, very quiet at idle.i change my engine oil every 3500 miles, I always have. I should add, the owners manual said that depending on climate, 5 30 or 10 30 is acceptable . I run 10 40 in my 58 cadillac year round. Been doing that for decades, my parents bought it in 1960. Thanks for your interesting tutorial.

[@TheRepairSpecialist]

Thank you so much for the nice feedback. I really appreciate it. Craig

[@spelunkerd]

Yes, the scale used is confusing if you carefully think about it. The warm test uses a different scale compared to the cold, so the two scales are not comparable. The key point is that all automotive oils will have lower viscosity at higher temperatures. Multigrade oils simply have a more gentle downward slope of the viscosity to temp curve, compared to monograde oils. One day I tried to add a litre of 5W30 oil at -40 deg C ambient temp to a warm engine. Molasses through a funnel, it took 20 minutes to drip through.

[@piecetoyou8285]

I would best explain it as; The oil gets stronger and the (strength) increases the hotter it gets, molecules become stronger more held to gather which makes them bond ie cling more to each other and stick to the metal better due to its elasticity, but stays the same in thickness , cold less bonding hot better bonding,

[@Middle-of-nowhere]

These numbers are really confusing The number before W expresses the internal friction of the oil due to external force called dynamic viscosity Can we pump it or can we stir it Can we get it to move On the other hand the number after W expresses the kinematic viscosity of the oil due to gravity I really thank you for such videos If you can make a video about HTHS Viscosity and why it’s getting momentum lately

[@thomaslau8806]

Thank you for the good explanation!!

[@TheRepairSpecialist]

You are welcome! 👍👍👍

[@petemoss9693]

Very Good Video -

[@DG-od4si]

nice video, thanks

[@woozyinyahead27]

Awesome knowledge. Always enjoy

[@elvinkasumovic3296]

Can you explain fuel viscosity and coolant viscosity propertis? What hapens if external liqueds meat ore match same oil viscosity propertis? Wuld they bound?

[@AbderrahimSeck]

What oil index is to use in hot weather (15c° to 34c° in winter and up to 25c° to 48c° in the summer) for a toyota corolla 2018 model as the manufacturer recommends a 0w16 ? Is it possible to use a 5w40 or a 10w50

[@BrainHurricanes]

Thanks for explaining more. So a 5W30 has a SAE of 5 when cold, and a SAE of a cold 30 that is now hot. I still think they used a confusing method. It's feels like comparing apples with oranges.

[@TheRepairSpecialist]

A cold 5 and a hot 30

[@BrainHurricanes]

@@TheRepairSpecialist Now you got me really confused. So the oil is indeed thicker when hot ? I'd like to see that in a rundown. Cold vs hot side by side, and the cold is going to finish first ? Thanks for explaining, my brain does not want to co-operate.

[@TangoNevada]

@@TheRepairSpecialist Thought I would ask directly - With this in mind, what does the Zero mean in 0W-20 for example? Does it mean, there is no difference between the oil when it's cold vs Hot? Thank You

[@GarthThomson]

Can I ask if it’s fair to say that the base oil is a 5 and though it would thin out as it gets hot the additives in it thicken as it gets hot and the result is the multigrade oil /additive mixture maintains it’s viscosity and stays at a cold 5 equivalent which is very close to the viscosity of a hot 30?

[@GarthThomson]

What is really interesting is that a cold 5 weight oil (as you pour it from the can) is thicker than a hot 30 weight oil! It’s certainly very thin as it pours from the sump plug hole when it’s just warm. A hot 5 must be crazy thin.

[@TangoNevada]

What about 0W-20? Does that mean there is no difference between the viscosity when cold vs hot? Thanks

[@johnfranklin5277]

Did you watch the video? Cold, 0 w , hot becomes 20 wt. If there was no difference. Would just say 0 wt, period.

[@TangoNevada]

@@johnfranklin5277 Wow, you take oil very seriously.

[@gotj]

Something is wrong or missing in this explanation my friend, because cold oil is never thinner than hot oil.

[@TheRepairSpecialist]

Did you get my last message to you with a link to an explanation??