Why Do Knowledgeable Folks on Here use 20 wt Oil

[TurboZedd-R]

My K20 is probably ruined after 12k miles on a 0w20 at 3k intervals. Probably should run something other than what Honda puts on the oil cap.

 

[TomYoung]

Just sayin'

View attachment 264541

What about the thin domain?

 

[OCD-OCI]

For me, going up one grade removes any doubt that the oil is thick enough for my 2.4T motor. And I like the smother and quieter engine. No harm, no foul.

 

[DirectRejection]

Yes we understand that the differences in UOA analysis between 20 and 30 wt oil are slight. But we also know 30 wt protects better. The 3 factor Bearing Graph says that.

We also know that 20 wt. oil was first considered 20 years ago to improve gas mileage. It was shown that engines at that time would not last to 150 K miles as they would be required. So they lowered that requirement. And fast forward engines were redesigned with larger bearings and bearing surfaced to provide for less wear.

Still in light of this there is every reason to suspect that an engine will last longer over the longer haul and/or use less oil over that period by using 30 wt. oil. So do knowledgeable folks value the fact that engines will give 3% to 6% better mileage??

To answer the question asked in the thread title, it is because the "knowledgeable folks" are actually knowledgeable about the specifics involved.

 

[Runalot]

What about the thin domain?

Ahh yeah!

Maybe we create a forum using the thickversusthin domain and only allow thick v thin debates.

 

[Mackelroy]

I live in a state that has cold weather and we all know that much of the wear in an engine occurs at start up. Thinner oils flow better at low temps and may help my engines last longer.

Yes in freezing range temps, but also heavy oils (50 weights) in general tend not to run off engine parts as easily as thinner oils with shut down periods. Giving the thicker oil an equal chance with start up , cause of that heavier layer of protection, even though wont flow as fast on start up.



or atleast ive not seen a 50 oil weight engine, destroy itself via startup with normal temps. I have seen thin oil leave nothing but dry on lobes, but heavier weight its obviously holds there.

 

[Revving2Redline]

UOA's can't be used for that purpose.

No, SAE 20 grade oils have been around since before WWII. I've seen Gray Marine engines with brass grade plaques on the final drive that listed SAE 20, SAE 30, SAE 40 and the intended temperature range for each grade in the engine.

No, the wider bearing changes were made to accommodate oil grades BELOW the SAE 20 threshold; below the 2.6cP HTHS limit, which is where design changes need to be made. It was Honda, Toyota, Nissan...etc that were experimenting with grades that weren't even ratified in J300 at the time, but had HTHS viscosities below 2.6cP, that discovered the need for wider bearings, along with surface coatings and other mechanisms to keep wear to an acceptable level.

There isn't a 3-6% improvement in mileage going from an xW-30 to an xW-20, it would be much less than that, based on what Mobil shared with their AFE oils.

As long as oil temperature is properly controlled (and many applications that call for xW-20 have heat exchangers for the oil to keep it in a specific temperature range), xW-20 is generally safe (it is, after all, spec'd by the OEM). However, some applications, with fuel dilution and poor oil temperature control, I wouldn't feel safe running an xW-20.

So, for me personally, it comes down to application. Just like I prefer an additive package with non-neutered AW chemistry.

I like you more and more each day. Well written.

 

[OilUzer]

Re: Title of this thread

We have to leave some room for the possibility that "knowledgeable folks" may not be as knowledgeable as one might think! No?

 

[4WD]

Some run 0W20 + OEM approved under warranty …
Then bump to 5W30 with an engine that’s still in good condition …

 

[4WD]

Re: Title of this thread

We have to leave some room for the possibility that "knowledgeable folks" may not be as knowledgeable as one might think! No?

What did Clint pick with a fistful of dollars?

 

[4WD]

No, but the floor of 2.6cP for HTHS is the threshold where you need to make engine design changes, which I think is an important distinction. The old monograde SAE 20 oils had a higher HTHS, but there were other xW-20 grades available, probably the most common being 20W-20, but there was also 15W-20 and 10W-20 and even 5W-20 (the original M1).

Also consider that when some dropped to a 20 - that piston jets and oil coolers were added to the mix …
Overall, design/manufacturing technology brought 3D accuracy - and the need to stiffen up the lower end …

 

[Kalle.J]

Some run 0W20 + OEM approved under warranty …
Then bump to 5W30 with an engine that’s still in good condition …

Some = Some Americans.
This is not even an issue anywhere else.

 

[4WD]

Some = Some Americans.
This is not even an issue anywhere else.

Doubt you would know that …

 

[tolian21]

my car ends up with 4-5% of fuel, and UOA shows that Xw-30 oil thins to have the same viscosity ad Xw-20. In some cases thicker oil is just a way to offset viscosity loss

 

[PontiacHO]

Of course-my 5.3 should have blown up running 0W/20 pulling a 5,000 pound travel trailer up to 10,000 feet elevation on a 90 degree day.....

My 5.3 GMC has also had 0w20 towing my boat and numerous U-Haul moving trailers. 100k miles and counting….

 

[PontiacHO]

I am following Mexican owner manual for my Acura RDX that allows 5w-30, but the same manual in USA only has 0w-20. I am following the engineers that wrote Mexican manual. Is it wrong?

I would do the same in your case.

 

[Glenda W.]

I am following Mexican owner manual for my Acura RDX that allows 5w-30, but the same manual in USA only has 0w-20. I am following the engineers that wrote Mexican manual. Is it wrong?

Me too. The Mexican and Australian “engineers” do seem to write a good owner’s manual!!

 

[OilUzer]

What did Clint run with a fistful of dollars?

Dino and shorter OCIs with good results!

 

[TomYoung]

Yes in freezing range temps, but also heavy oils (50 weights) in general tend not to run off engine parts as easily as thinner oils with shut down periods. Giving the thicker oil an equal chance with start up , cause of that heavier layer of protection, even though wont flow as fast on start up.



or atleast ive not seen a 50 oil weight engine, destroy itself via startup with normal temps. I have seen thin oil leave nothing but dry on lobes, but heavier weight its obviously holds there.

Dry lobes when using 0 w 20 oil in the cold at startup. You’re going with that?

 

[SubieRubyRoo]

What about the thin domain?

It’s available!