Why HTHS 3.0 Minimum Is Preferred By Many ?

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Through various threads here an "HTHS 3.0 minimum reference" is stated as the base line minimum for engine protection . That would then seem to render HTHS readings below 3.0 (i.e. 2.7) to be inferior or at least less than desirable in engine protection . Perhaps stated another way : "What makes an HTHS of 2.7 less desirable than an HTHS of 3.0 and above ? ... Are their tests of HTHS 2.7 and HTHS 3.0 run side by side in the same temp , load , RPM , etc. conditions that show a clear difference in protection ?
 
I suppose that oil that evaporates and shears less under load is desirable but unless coupled with other attributes may be meaningless. For example: an oil that has a high HTHS but say a cold pour point of 40 degrees F probably would be harmful to engines anyplace except the tropics. Many modern oils have given up some HTHS for a lower viscosity and improved economy. With the right add pack and other attributes the HTHS seems less relevant than your hard and fast rule would seem to dictate. Most of these new 16 weight motor oils have relatively low HTHS numbers.
 
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Originally Posted by ChrisD46
Through various threads here an "HTHS 3.0 minimum reference" is stated as the base line minimum for engine protection . That would then seem to render HTHS readings below 3.0 (i.e. 2.7) to be inferior or at least less than desirable in engine protection . Perhaps stated another way : "What makes an HTHS of 2.7 less desirable than an HTHS of 3.0 and above ? ... Are their tests of HTHS 2.7 and HTHS 3.0 run side by side in the same temp , load , RPM , etc. conditions that show a clear difference in protection ?

Your Korean engines-designs desire more frequent oil changes. Buy a brand name that you like - in the viscosity range of your owners manual and keep rollin'.
 
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I don't think there would be a difference in wear or protection for the average driver. For me it's an insurance policy. I keep my vehicles until I die. If the vehicles die I fix them. I like to stay in the 3.0 to 3.5 range.
 
Originally Posted by ka9mnx
For me it's an insurance policy. I keep my vehicles until I die. If the vehicles die I fix them.


Hope your insurance policy has great life insurance coverage. Do not die on us ka9mnx.
 
My opinion has been-use what the manufacturer suggests, as long as the mfr. seems to know what they're doing, and the engine doesn't wear enough that oil pressure starts dropping. Unfortunately, with CAFE going a little wild, I'm not too sure some of the manufacturers really know what they're doing (I'm looking at you, Hyundai/Kia & FCA [Ecodiesel]}!
 
Originally Posted by ChrisD46
Through various threads here an "HTHS 3.0 minimum reference" is stated as the base line minimum for engine protection . That would then seem to render HTHS readings below 3.0 (i.e. 2.7) to be inferior or at least less than desirable in engine protection . Perhaps stated another way : "What makes an HTHS of 2.7 less desirable than an HTHS of 3.0 and above ? ... Are their tests of HTHS 2.7 and HTHS 3.0 run side by side in the same temp , load , RPM , etc. conditions that show a clear difference in protection ?


Well, as you know, HTHS is pretty much the true measure of how much oil is actually flowing through where it is supposed to go at temperature and when it is hotter than blazes outside etc. The synthetics don't shear down. This site is cool and all, but it is still comprised of humans, sometimes, experts! Source: Them - that have their own individual attitudes and other things towards brand, how to measure oil, how to prop up their own oil, how to tear other oils down, ..in some threads, good base stocks make the oil. In other threads, they then don't matter.

If the HTHS is consistent with the SAE grade it says on the engine cap for your car then you should be great, and the rest is just healthy discussion in a good spirit and not nasty bickering about what might not even be applicable law.. the HTHS of an oil that meets the grade supposed to be in the car more than likely specified in something such as 5W-20 is not a disqualifier of that oil.

In conclusion, the minimum HTHS of a 5W-30 is 2.9, so having an oil with an HTHS 3.0 is probably indicating some kind of sweet spot of a Thick 20 if you wanted to say, I was not aware of the statement people prefer an HTHS of 3.0 although I can see why that would be attractive. Would have to indicate that it is all relative, as to your post.
 
I lost trust in what the manufacturer suggests when Ford back-specd my 1960's designed 300ci inline six to 5w-20. I tried it and it wasn't pretty.
 
Originally Posted by ka9mnx
I lost trust in what the manufacturer suggests when Ford back-specd my 1960's designed 300ci inline six to 5w-20. I tried it and it wasn't pretty.


Yeah, the back-spec has also had spectacular badness on Volkswagen etc. What happened to your Ford?
 
I also tried the back spec'd 5W-30 once in my old 1992 Escort which was originally spec'd for 10W-40 or 15W-40, never again.
The engine and specially the hydraulic lifters hated it with passion, it sounded horrible, put 15W-40 HDEO back in it and guess what i had a smooth running quiet engine again, expensive Mobil 1 too, proverbially down the drain with just 250 miles.
 
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Originally Posted by talest
ka9mnx said:
I lost trust in what the manufacturer suggests when Ford back-specd my 1960's designed 300ci inline six to 5w-20. I tried it and it wasn't pretty.

Why would you want to do that?
 
Originally Posted by talest
Well, as you know, HTHS is pretty much the true measure of how much oil is actually flowing through where it is supposed to go at temperature and when it is hotter than blazes outside etc.


What? No, HTHS is the measure of VISCOSITY (not oil volume) under high temperature (150C) high sheer conditions. Think of it is as the viscosity the bearings see.

Originally Posted by talest
The synthetics don't shear down.


Yes they do. There are VERY few monograde synthetics out there sold as multigrades. They may have LESS VII polymer in them, on average, than your typical "conventional" oils, but they certainly still contain it.

Originally Posted by talest
If the HTHS is consistent with the SAE grade it says on the engine cap for your car then you should be great,

And this is why we check the owner's manual. Typical HTHS for a GF-5 ILSAC 5w-30 for example will be somewhere between 3.0cP and 3.2cP. Typical HTHS for a Euro 5w-30 (same SAE grade) will be 3.5cP +. Like kinematic viscosity varies inside a grade, so too does HTHS, with ILSAC oils being on the low-end typically and many Euro examples on the high end.
 
If you are a Hyundai owner, which I am, you do have to concern yourself with what oil you use. Hyundai has crap oil You could be in the 14% of tanking your motor because Hyundai has been having an 8 year battle with oil film boundary layer issue that they semi falsely blame on a run of engines that did not have the machining chips blown out years ago. I had a 2013 Hyundai Elantra with a 1.8 liter that is not on the Hyundai motor list of recall, because it is on a double secret "warranty fix" list that they don't want the governments to ADD to the list of engines Hyundai can't seem to build correctly. Mine tanked at 14,000 miles, with very low oil change intervals (3,500) Mobil 1. One dealer had 200 plus cars waiting for new engines and had their sister/other brand name dealerships installing Hyundai engines because they could not keep up.

I am gambling AGAIN on a Hyundai as I bought a 2018 Kona AWD 1.6T which has been one of their better motors. It does "get used" since it has been Eibach lowered/new rims/tires and with AWD is a killer handling car. I was running 5w-30 Mobil1 ESP in the winters and now am using Amsoil 0w-40 SS in the summer. I change at 3,000 miles since I am a short tripper/ Minnesota winters=dilution and I am on boost more then average. All Hyundai turbo's are in LSPI warning zone since you get full boost (17psi) at 1,600 rpm in a 10:1 compression turbo motor. Even though Hyundai says 87 octane is ok, nothing less then mid grade sees my tank.

Hyundai has also moved up their oil grade on 2.0T motors from 5w-30 to mandate 5w-40 in those engines in a TSB. Again, trying fighting their oil film boundary layer issue.

.
 
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Is it law by the API that says each grade oil "must" be between the min/max hths or is it just a rule of thumb for manufacturers? Im not sure who drew this.

Engine-Oil-Viscosity-Classification-J300-.png
 
Originally Posted by GaryPoe
Is it law by the API that says each grade oil "must" be between the min/max hths or is it just a rule of thumb for manufacturers? Im not sure who drew this.


That's a chart of J300, which shows the limits for each grade. As you can see, the minimum HTHS acceptable for an xW-30 is 2.9cP with no maximum. For KV however, there is a max KV100 of 12.5.
 
Also, will the hthsv shear the same more/less than or be effected by dilution more/less than the other shear factors or vii's and what not. If I run a 5w30 with a hthsv of 3.0 for 10k miles, what will the hthsv shear to? Would more vii help protect the hthvs from shearing over time or would it have the same shear rate with or without vii all together?
 
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Originally Posted by Mainia
If you are a Hyundai owner, which I am, you do have to concern yourself with what oil you use. Hyundai has crap oil You could be in the 14% of tanking your motor because Hyundai has been having an 8 year battle with oil film boundary layer issue that they semi falsely blame on a run of engines that did not have the machining chips blown out years ago. I had a 2013 Hyundai Elantra with a 1.8 liter that is not on the Hyundai motor list of recall, because it is on a double secret "warranty fix" list that they don't want the governments to ADD to the list of engines Hyundai can't seem to build correctly. Mine tanked at 14,000 miles, with very low oil change intervals (3,500) Mobil 1. One dealer had 200 plus cars waiting for new engines and had their sister/other brand name dealerships installing Hyundai engines because they could not keep up.

I am gambling AGAIN on a Hyundai as I bought a 2018 Kona AWD 1.6T which has been one of their better motors. It does "get used" since it has been Eibach lowered/new rims/tires and with AWD is a killer handling car. I was running 5w-30 Mobil1 ESP in the winters and now am using Amsoil 0w-40 SS in the summer. I change at 3,000 miles since I am a short tripper/ Minnesota winters=dilution and I am on boost more then average. All Hyundai turbo's are in LSPI warning zone since you get full boost (17psi) at 1,600 rpm in a 10:1 compression turbo motor. Even though Hyundai says 87 octane is ok, nothing less then mid grade sees my tank.

Hyundai has also moved up their oil grade on 2.0T motors from 5w-30 to mandate 5w-40 in those engines in a TSB. Again, trying fighting their oil film boundary layer issue.

.
I'm still trying to see the logic on the grenading Hyundai engine issue-it takes 50K or more to kill one because of sloppy cleaning of the block?? How the heck does it ever make it to the first oil change?? I've been calling bull shiitake on it since DAY ONE!
 
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