15w/50 in place of 0w/20 WHY?

[hattaresguy]

I know its shocking but manufactures actually do a bit of testing. But of course hearsay and gut feelings are more fun and trump engineering.

I mean clearly Toyota never imagined anyone would take their pickup truck and hook a trailer up to it, and tow...in hot weather! The horror!

 

[Shannow]

Personally, if it were my vehicle, I wouldn't do it...there are plenty of 40s to go around, of all sorts of flavours.

That being said, risk of damage is next to nil, the the higher HTHS will provide greater margin before boundary/mixed everywhere it's (nearly) occurring. Thicker film MOFT all round.

I'd expect that he should be feeling the thicker oil on the butt dyno...I know that I did on 25W-70 one winter in my underpowered J-Car some winters ago...same time for oil light to go off, cams leaking oil through the lube holes virtually instantly at -7C.

 

[Garak]

Originally Posted By: Swifty
The UOA was to compare wear between the 50 and 30 weight as I said to him why not run a 30 weight in place of a 50. Hard to say if there would be a major difference in wear metals in the samples but I thought it might be fun to see.

As we know, UOAs are not a good way to compare wear between two different oils.

 

[demarpaint]

Originally Posted By: aquariuscsm


15W50 will work just fine in your friend`s car. Only negative effect it will have is it will hurt the 0W20`s feelings haha.


LOL. Yes 0W20 can be very sensitive at times. It hates being called thin. LOL

 

[Swifty]

Originally Posted By: Shannow
Personally, if it were my vehicle, I wouldn't do it...there are plenty of 40s to go around, of all sorts of flavours.


This was what I was trying to get at why not use a 30 weight or even a 40 weight. Plenty of good flavors for both that would serve anyone well in that car without killing the gas mileage as much and feeling as sluggish and still provide plenty of protection.

 

[Swifty]

Originally Posted By: Garak

As we know, UOAs are not a good way to compare wear between two different oils.


Your right a UOA is better used to see if the fluid is serviceable.

 

[Garak]

In any event, I don't doubt a 15w-50 would protect fine. There are other choices, though.

 

[virginoil]

FrankN4 used Mobil 1 15W-50 in all of his vehicles and I believe he is a credible poster.

Not as stupid as some of you that are thin from the neck up claim it to be.

Below are the links to a similar query thread from 4 years ago.

Try these links in Google as I could not get these to work in the post if are interested.

Top link doesn't work in the post but the bottom one does.

https://bobistheoilguy.com/forums/ubbthreads.php/ubb/showflat/Number/1599767/Searchpage/1/Main/115210/Words/15w50/Search/true/Re:_Mobil_1_15w50#Post1599767

https://bobistheoilguy.com/forums/ubbthreads.php/topics/1598148/1

 

[aquariuscsm]

What ever happened to Frank?? I haven't seen him on here in years.

 

[CATERHAM]

The main problem that hasn't been mentioner in running a 50 grade oil in a 20 grade application even when the oil is up to temperature is reduced oil flow at high rev's.
The oil pump will likely be well into by-pass mode. This is more of a potential problem under track conditions when high rev's are maintained.
The reduced oil flow often results in higher oil
temp's. Some engines tolerate this better than others but engine failure can result.

Running 2 to 3 grades heavier than necessary is always problematic. If you think you may need to run a heavier oil get your oil pressure checked first if you don't have an installed OP gauge.
Your OP will likely be well above the test spec' even at fully hot oil temp's on the spec' oil. That should be enough to disuade one from running anything heavier.

 

[kmrcstintn]

Quote:
The winter time needs quick lubrication, but in the summer it needs the 20-50 because of lubrication. It provides a thicker oil film between moving parts,


some motorcycle/scooter owners do this with their oil changes...thicker stuff in warm/hot weather and thinner stuff in cool/cold weather

 

[Shannow]

Originally Posted By: CATERHAM
The main problem that hasn't been mentioner in running a 50 grade oil in a 20 grade application even when the oil is up to temperature is reduced oil flow at high rev's.
The oil pump will likely be well into by-pass mode. This is more of a potential problem under track conditions when high rev's are maintained.
The reduced oil flow often results in higher oil
temp's. Some engines tolerate this better than others but engine failure can result.


You've mentioned two sorts of failures that you've seen 50s do on the racetrack....

this one, where the overly thick oil gets too hot, causing the engine to fail, and the other one, where the overly thicvk oil starves the engines of oil

Have asked a coupleof times for the specific examples and the evidence for each, but you seem to lack the time to provide the data.

Originally Posted By: CATERHAM

Your OP will likely be well above the test spec' even at fully hot oil temp's on the spec' oil. That should be enough to disuade one from running anything heavier.


There's that pressure equals lubrication thing again

 

[CATERHAM]

Originally Posted By: Shannow
Originally Posted By: CATERHAM

Your OP will likely be well above the test spec' even at fully hot oil temp's on the spec' oil. That should be enough to disuade one from running anything heavier.


There's that pressure equals lubrication thing again

There's your ridiculous strawman argument again.
As anyone with half a brain can see, I never said "pressure equals lubrication", those are you words. OP is a proxy for operational viscosity, nothing more.
And since you think it is such a good idea to run 1-2 grades heavier that spec' for the additional "head room" (gotta love that scientific phrase) it provides, I doubt you even have a clue as to how much of the time your engine is operating with the oil pump in by-pass (which you claim is so "bad") or how high the oil temp's have to be before you're out of by-pass.
For someone with such a pedantic bent, it's funny that these little details are obviously lost on you.

 

[Gokhan]

Lowest viscosity recommended by the manufacturer is the correct viscosity for most driving conditions, as lower viscosity has so many tremendous benefits (more flow, less pressure and strain, cooler oil and engine, better fuel economy, perhaps even better cleaning, and so on).

However, for severe loads (high speeds on uphill grades, wide-open throttle, towing, etc.), higher viscosities will potentially result in less wear or offer a larger margin before accelerated wear starts.

 

[Shannow]

Originally Posted By: CATERHAM
Originally Posted By: Shannow

There's that pressure equals lubrication thing again

There's your ridiculous strawman argument again.
As anyone with half a brain can see, I never said "pressure equals lubrication", those are you words. OP is a proxy for operational viscosity, nothing more.


Repaeatedly, I have agreed with you that OP measures operational viscosity

Your technique is measured in the high shear enviromnment...however (and obviously), it is measured in the unloaded area of the bearing

I have stated that this technique does NOT demonstrate, and you have never countered, provide cogent argument, or even a link to
a paper that this operational viscosity is sufficient to provide hydrodynamic lubrication in the bearings

You are measureing one thing (oil pressure), correlating that to operational high shear viscosity (correctly), and then stating that it provides adequate protection, which is not a a logical conclusion that can be drawn

In arithmetical terms, your equation for viscosity is
CHoperational viscosity is proportional to pressur
Protection is related to CHoperational viscosity

Therefore, you are arguing directly that oil pressure tells you if you have lubrication...



Originally Posted By: CATERHAM
"head room" (gotta love that scientific phrase) it provides


I'm glad tha the term brings you joy

When I first started using the term, I was in "debate" for want of a better word, with a technically inept individual with zero training in such things...Concversation became mired in "don't believe" (scientific principals), "do not feel" (engineering basics),

Said individual was becoming increasingly obstreperous, so in trying to bring in terms that the individual COULD understand, I likened the safety margins to "headroom", a term that I thought the poster could understand

You may remember the thread when it was first used, as you were a major contributor in that thread

At least it sunk in

As to the rest (and continuation of) your assertions of what I sate and beleive, most of which you make up to suit yourself, I'll leave them for now

But obviously, as you'v got some time on your hands, how about you dig out the details of the pile of failed engines that you've personally seen on the racetrack, and the forensics that diagnosed the thick oil issues...and revisit the scientific analysis of how viscosity index is calculated, error bands, and what an acceptable range of numerical outcomes from such an investigation should yield

I beleive that task sits within the realms of YOUR qualifications, however, you are even arguing against statistical techniques these days.

 

[CATERHAM]

Nice obfuscation (dodge) of the issue. You're very good at it, I'll give you credit for that.
I'll ask you again. What do you "feel" you're achieving in running 1 to 2 grades heavier than specified? Are you actually seeing very high oils temp's? Do you even know what your oil temp's are?

 

[jrustles]

Originally Posted By: Shannow
Originally Posted By: CATERHAM
"head room" (gotta love that scientific phrase) it provides


I'm glad tha the term brings you joy

When I first started using the term, I was in "debate" for want of a better word, with a technically inept individual with zero training in such things...Concversation became mired in "don't believe" (scientific principals), "do not feel" (engineering basics),

Said individual was becoming increasingly obstreperous, so in trying to bring in terms that the individual COULD understand, I likened the safety margins to "headroom", a term that I thought the poster could understand


haha ouch! i'd hate to be the subject of that lashing.

Originally Posted By: CATERHAM
What do you "feel" you're achieving in running 1 to 2 grades heavier than specified? Are you actually seeing very high oils temp's? Do you even know what your oil temp's are?


To be fair, I don't think anyone ITT suggested that using SAE50 (3 grades up) was something worth trying to achieve something.

However, alluding to the use of 30 and 40 grades (1 and 2 grades up) as being totally out of line, immoral, catastrophic or destructive is hardly reasonable. It's IMO this (classic?) knee-jerk reaction against the 'egregious' and 'decadent' use of 'molasses-like', 'virtually solid' 30 grades and 40 grades that is totally ridiculous, out of line and sensationalist.

These people are masters of logic(al fallacy) and so invested in their own theories, often backed by misappropriated science (if that), that they cannot fathom REALITY or just how off-based their viscosity fears are.

I think that's the crux of this issue; perpetuating disproportionate, unfounded and unreasonable fear. That has got to stop.

It's one thing to feel like we're advanced because we're on BITOG and chuckle at mere mortals who are misguided in their ways, but it's another thing to do that and ironically suffer from the same 'reality disconnect' as the person you're smugly mocking.

20/30/40 even 50 grades are so incredibly close to each other, in the realm of rheology. WHY is it so easy for some to overlook the fact that a common 0w20 is @40C (not cold at all) is `'4 times' more viscous than a hot 20w50. The low VIS "nationalists" would never refer to the 0w20 on hot sunny day as "molasses" ready to destroy cam phasers and piston rings, let alone that same 0w20@-25C.

If you want to make a case for destruction or disadvantages of 'non-optimal'(whatever that means) viscosity choices, then how about OBJECTIVELY and DIRECTLY addressing the SPECIFIC lubrication issues and mechanical disadvantages of the case you want to make.

That entails some type of documented support for cases of COMPROMISED WEAR protection by using a grade or two up, or damage to hydraulic components, etc. to whatever case one wants to make.

Protip: none of that relates to warm-up fuel economy optmization, THE goal and most widely acknowledged and documented driving force for investigating and developing low HTHS, high VI oils. Generally improved wear protection vs the current fluid is NEVER mentioned as being a criteria that drives development, JUST FUEL ECONOMY.

If anyone can find a proper example of an API, non-racing, low HTHS oil development being primarily driven by engine wear protection, by all means post em.

 

[yvon_la]

Does this mean i could have same expected effect from and oil that can only pressurize oil at say 8 psi vs car maker expected 10 psi?there must be a reason.otherwise all car maker would vouch for 0w20 and so far most vouch for 5w30 .synthetic or dino

 

[tommygunn]

maybe he has an oil leak?

 

[Ken2]

Quote:
I am currently having an argument with someone who insists on using M1-15w/50 in a vehicle spec'd for 0w20 (2013 civic si k24)and wanted to know why one would do this. I'm curious and want to understand! Supposedly this person has 30 plus years in engine R&D(which is oil related)including small engines, weed eaters diesel applications etc etc. He lives in a hot climate and all I could get out of him was friction equals wear.
Ask him how a 90,000 hp jet engine lives with 5 wt oil. How does a very large diesel engine making 7,500 hp per cylinder live with 30 wt crankcase oil...and this is a case where a crankshaft replacement is a mammoth job that is done only in the case of a casualty, never due to normal wear over the 20+ years of the ship's life. (Chevron Veritas 800 SAE 30 is one example.)