Thin vs Thick Discussion Chapter 1

OVERKILL

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I enjoyed reading this so far, quite enlightening for me, a neophyte, on all the nuances of lubricants and their classifications. One thing I take away from this is the quibbling over the "W" as in 5W/20. For many years I believed it stood for weight and I see others here believe it stands for "winter". Winter is a subjective term that is interjected into all these tables of objective data and is useless in choosing an oil when I look at winter here in south Louisiana where we rarely drop below 32 degrees Fahrenheit and compared to someone who lives in Nome, Alaska who may see that temp in late spring. The only definitive answer for what "W" stands for in an objective measurement for the number the it follows is this quote posted by an earlier poster. So there it is, "W" means that the number preceding it is the viscosity measurement at -18 degrees C, (0 degrees F), a temperature I hope never to experience here in South Louisiana. :)
Now is it time for me to continue on to Chapter -2-.
View attachment 62221
Perhaps you missed my post on the first page of this thread that cited multiple sources including Castrol, Lubrizol...etc that all indicated that it stood for "Winter".

 

ZeeOSix

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Perhaps you missed my post on the first page of this thread that cited multiple sources including Castrol, Lubrizol...etc that all indicated that it stood for "Winter".

Valvoline who's been in the oil business for over 100 years also says the "W" stands for winter. But hey, what do they know? 😄
 
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I read this post (mostly) and I think its missing the point of Ferrari's oil recommendations. A lot of Ferrari drivers use their cars on the track. Ok maybe they drive to the track. Some Ferraris are not sold as street legal. Point is that oil is not just about flow when cold. You need viscosity to keep the oil on cylinder walls and such during high G turns, etc. Its a different engineering target than a commuter car with cold starts daily.
 
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I caught that too. I think he missed this part with his edit. This piece was written probably 15 years ago.
It was silly back then as well. I rebuilt a friends Pontiac 455 engine [stock rebuild] back then and on initial fire up up the oil pressure was over 80 psi on the gauge . One of the guys said watching said "you have too thick oil in the engine" I asked why he said that? The engine is at 2,500 RPM and the oil pressure should be 25 psi. I thought the guy read oil 101 and I was correct. The engine was running less that a minute.
 
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I've read a post on the toyotanation site on 0W-16 being speced for 2018+ Toyota Camry's. They have photos of the Toyota owner's manuals in Europe and Australia for the same engine specing 5W-30. High Temperate / High Sheer (HTHS) is connected with engine wear protection. The lower HTHS numbers the more engine wear. The HTHS numbers for 0W-16 are scary. Even the HTHS from 0W-20 are borderline.


When Ford switched from 5W-30 to 5W-20 years ago, they had a huge problem with increased timing chain wear.

The whole move to thinner oils is not to improve engine protection. Instead it's to save automakers money by reducing fines from the EPA over CAFE. The benefit in fuel economy is not measurable on an individual car, but the tiny fraction adds up over a fleet of hundreds of thousands of cars. The automakers don't care about engine wear after the car's warranty expires. They only care about avoiding the CAFE fines.

Thinner oils have much lower HTHS numbers. Thin oil's achilles heal is higher engine temperatures. Higher temperatures can occur when idling the car for extended periods on a hot day with the air conditioning on when the car is parked. Also, during extended stop and go driving on a hot day with the air conditioning on. Engine temperatures rise higher even with a healthy coolant system.

I understand and respect those people following their owner's manual recommendation on the ultra low viscosity oils 0W-16 and even 0W-20.

The best thing about car ownership is that you are the captain of your own ship, and you can make your own decision about which oil protects your engine the best.

I like to keep my cars for a very long time. I'd like to get 300k miles out of my cars, and protecting the engine is my primary concern.
After reading the entire toyotanation thread, and also after reading about the Ford Timing chain wear due to the switch to from 5W-30 to 5W-20,
I've decided to only use 5W-30 synthetic in all of my vehicles for better protection of the engine. It's such a great feeling of independence to ignore CAFE and it's forcing of automakers to go to thin oil at the expense of engine wear. It feels like July 4th, Independence Day!
 
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Nothing ventured ? I recently switched from 5w30 to 5w20 for the first time in my 07 4.0L gasoline Toyota FJ with 220k miles. I've posted 13 UOA here on the various oils I've run (extended) in it since 2010. The 14th UOA will be in about a yr. Heres the 13th: https://bobistheoilguy.com/forums/t...esp-5w30-10k-miles-on-oil.351353/post-6033835

Then, in our 07 Yukon Denali w/gasoline all aluminum 6.2L I'm switching from 5w30 to 0w20.

I like how the thinner visc oil flows more volume carrying away heat.

We'll see ???
 

ZeeOSix

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I like how the thinner visc oil flows more volume carrying away heat.
There is no more flow volume due to the fact that the oil is being delivered to the oiling system by a positive displacement oil pump. In fact, the PD oil pump might just be a little less efficient in pumping the thinner 5W-20 due to increased rotor slippage.
 
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There is no more flow volume due to the fact that the oil is being delivered to the oiling system by a positive displacement oil pump. In fact, the PD oil pump might just be a little less efficient in pumping the thinner 5W-20 due to increased rotor slippage.

An extreme example = pump honey then 0w20 thru the pump and the engine oil passages for 1 min and see which flows more volume, don't forget the thicker honey goes thru the bypass.
 

ZeeOSix

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An extreme example = pump honey then 0w20 thru the pump and the engine oil passages for 1 min and see which flows more volume, don't forget the thicker honey goes thru the bypass.
If the pump isn't in pressure relief (bypass) then the flow is the same if the pump efficiency stays constant. In order to get "honey", you'd have to be trying to start an engine at -25F with 20W-50, which isn't something should be doing anyway. Cold starting at any temp within the "W" rating of the oil, and not revving the engine very high until warmed up, should not put the PD in to pressure relief.
 
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If the pump isn't in pressure relief (bypass) then the flow is the same if the pump efficiency stays constant. In order to get "honey", you'd have to be trying to start an engine at -25F with 20W-50, which isn't something should be doing anyway. Cold starting at any temp within the "W" rating of the oil, and not revving the engine very high until warmed up, should not put the PD in to pressure relief.
Most engines I've owned go into bypass at idle when cold (<100*f).

My Yukon w/6.2L makes the same oil pressure(35psi) at hwy speed (2k rpm) at normal operating temp (210*f) with both 0w20 and 5w30. At cold startup (70*f) both oil weights make the same oil psi, 50 psi. I can rev the engine a little when cold and it doesn't go over 50 psi. Its in bypass.

My Toyota doesn't even have an oil pressure gauge?
 

ZeeOSix

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Most engines I've owned go into bypass at idle when cold (<100*f).

My Yukon w/6.2L makes the same oil pressure(35psi) at hwy speed (2k rpm) at normal operating temp (210*f) with both 0w20 and 5w30. At cold startup (70*f) both oil weights make the same oil psi, 50 psi. I can rev the engine a little when cold and it doesn't go over 50 psi. Its in bypass.

My Toyota doesn't even have an oil pressure gauge?
Is it a digital or analog oil pressure gauge? Lots of analog gauges aren't very accurate. What does the service manual say the oil pump pressure relief setting is?

50 PSI pump relief setting is the lowest I've ever heard of ... wouldn't say that's typical with the majority of engines. Most engines I've seen are more like 80 to 90 PSI to hit pump relief.
 

ZeeOSix

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Caps on all my cars say 5w30 and that's what she gets, no time for all the expert one-upmanship BS. :LOL:
🍿🍿🍿
What if it said 5W-20, but the previous years of the same engine said 5W-30 ... as in back speced?
 
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