Oil viscosity - more difference than I would have thought

[i-DSi]

Originally Posted by theholycow

When you think about it that way, I wonder if the change in fuel economy indicates that the old oil was not doing its job at all and the metal was riding directly on metal instead of having a film of oil sandwiched between to reduce the friction.

Not in my case. The 'old' oil had a very constant fuel economy from the first day I bought the car (2 months after previous owner let the oil change).
And very big coincidence: I change to 0W20 oil and my mpg rises like hell from the very first tank. As already said: long term will tell. Right now I'm recovering from an operation so not many miles last time. I'm curious.

[bowtieguy]

fantastic Bob! the bottom line is what we all want to see/know.

here it is in regard to lube...0w30 is the superior oil under ANY condition in a well maintained engine. there is debate about using thicker oil in worn engines, but that's another discussion.

0w20 is acceptable for cooler climates, less severe driving conditions, winter driving(most climates), etc. it could possibly yield the best FE and emissions compared to heavier weights of conventional oil, but has yet to be determined to better that of a good 30 weight synthetic, especially a 0w30.

it's pretty simple guys, you'll use it or you won't. my question would not be one of everyday lube or FE, mine would be how will my oil stand up to severe conditions like summer, overheating, etc.

again, if you live in a cooler climate, knock yourselves out. i've seen first hand what florida heat and humidity does to inferior oils. you want to use them, and change them sooner, then fine. i'd use a true synthetic tho. there's a local, reputable, and long time mechanic that has reported on engine wear on vehicles that are recommended by the factory to use 0w20.
__________________________________
ya know, i've got an experiment that illustrates tire pressure up to a certain point caps out it's gains in FE. in MY app, it seems that higher pressure does not have much affect(to a point). but, i'm not going to debate it, i will or i will not over inflate.

[bobc455]

Originally Posted by theholycow

When you think about it that way, I wonder if the change in fuel economy indicates that the old oil was not doing its job at all and the metal was riding directly on metal instead of having a film of oil sandwiched between to reduce the friction.

I'm doubting it:
1) The oil I was using previously was thicker, and theoretically should have been protecting better
2) If there was actually metal-to-metal contact that drew that much energy, I would assume that there would be rather extensive wear occuring (to the point where my engine would probably be defunct by now).

I might try some 5W20 or 0W20 this winter. But in summer, I'm sticking with the 5W30.

As an aside, while I was on vacation 1100+ miles from home, I was victim of the GM Dexcool curse and had to spend a day replacing my intake gasket in a storage bay. The nearest parts store was about an hour away. But it was cheaper to buy $250 of parts, supplies, and tools, than to have a garage do the work (besides they'd be closed on sundays).

-BC

[GasSavers_BEEF]

i-DSi,

maybe my comparison is flawed because I am speaking of american vehicles. even our small economy cars have almost as much torque as they have HP. also, our torque is in foot pounds vs newton meters.

it may be just on the newer cars too.

[bowtieguy]

Originally Posted by bobc455

I might try some 5W20 or 0W20 this winter. But in summer, I'm sticking with the 5W30.

As an aside, while I was on vacation 1100+ miles from home, I was victim of the GM Dexcool curse and had to spend a day replacing my intake gasket in a storage bay. The nearest parts store was about an hour away.

once again you're a voice of reason here Bob.

doubters have refuted the dexcool issues as well. it seems you found out first hand the truth. my source, btw, on the oil recommendations(anti-0w20) is the same mechanic that lead a class action lawsuit against GM in the dexcool debacle, not to mention the same in toyota'a sludge issues.

disclaimer: it should be noted that GM's intake design was a factor in that suit in addition to the ill-advised 100k coolant exchange recommendations.

and toyota's block issues were a factor in their suit in addition to ill-advised extended oil change recommendations.

[slurp812]

Originally Posted by bowtieguy

not likely, especially soon or immediate evidence of such. i wonder how much engine life is SHORTENED by using 20 weight in warm climates, excessive idling, daily a/c usage etc?

shortened or premature is relative to be sure. 100k? 200k? 300k? what is fully mature?

We shall see. I run 5-20 all the time in my car, 125,000 and counting. Still runs like new...

[add|ct]

Originally Posted by bobc455

I'm doubting it:
1) The oil I was using previously was thicker, and theoretically should have been protecting better
2) If there was actually metal-to-metal contact that drew that much energy, I would assume that there would be rather extensive wear occuring (to the point where my engine would probably be defunct by now).

I might try some 5W20 or 0W20 this winter. But in summer, I'm sticking with the 5W30.

As an aside, while I was on vacation 1100+ miles from home, I was victim of the GM Dexcool curse and had to spend a day replacing my intake gasket in a storage bay. The nearest parts store was about an hour away. But it was cheaper to buy $250 of parts, supplies, and tools, than to have a garage do the work (besides they'd be closed on sundays).

-BC

Being that all of this is relative to application I thought thicker(relatively speaking) oil would indeed cause MORE wear(over measurable time; as in quite a few OCI or over a couple years of your engines life etc, if its thicker than spec for your car).

Why? Thicker oil is restricting oil flow(even if pressure is high that doesn't ensure 'protection', right?):

So, define protection. From one aspect, its adequate lubrication without interrupting; as it were, the normal operation of the engine.

Thus, allowing the longest life possible for YOUR engine is a result of minimized wear and 'other' protection from extreme environments(hot or cold) outside of just lubrication concerns. Thicker oil may increase oil pressure ya know, heh, and keep metal on metal from happening(quote un quote) but doesn't guarantee that compared to a thinner oil will protect the longevity of an engine if its causing more wear than the thinner oil. If the internal parts have to 'work' against the thicker oil compared to the thinner, you ultimately may have the car work itself 'to death', so to speak, or at least cause more fuel consumption(thus the FE gains over the long use of 0w oils etc)

The protection from metal/metal worry for a thinner oil is due to misinformation or a 'result' of just plain wrong use for a car's application. If you use any product right it will do the job its capable of. It's the users fault for letting it go too long of an OCI, driving habbits, changing oil grades outside of factory spec etc.

Just some thoughts and really statements open to being corrected, because I may be off base from what I'm trying to say. It's not my goal to blow anything out of proportion. If an engine is 'badly worn', you may be best with the 'thicker' oil if you have a relative drop in oil pressure using a thinner in this case below:

I've seen a few posters from muscle car forums that have more success with using thicker oils on their cars because its already having oil loss problems from engine wear/blow by/seals re-seating etc(most likely due to high rev/lead foot or other driving habits ...They also have issues with losing oil via PCV, the effects of this cycling oil into their car's intake and killing fuel octane(potential for issues there obviously the first being knocking) and thus the need for internal cleaning of the intake manifold/throttle plate/valve cleaning etc.

I'd venture to say that is more of a problem to create a 'need' for cleaners to a fuel line than any 'decent' gas stations gas being 'bad'...yet what is put in through the fuel system isn't really helping this problem. The last thought here is that I've recently used Amsoil's power foam(a top end cleaner), like the Mopar CCC, on the VX last week. It helped out the start and go immensely, certainly was a nice smoke show, and cleaned my throttle plate as well. The car drives so much smoother, makes me wonder how it felt when brand new from the factory? Anyway, got some video from a camera shot at my side mirror if anyone is interested, but not to get off topic. The point is if that happens on the intake of a car, from the oil fumes being put back into the intake via PCV leaving varnish on my VX, imagine a muscle car having problems with oil coming through the PCV and causing deposits along the intake. We're not even talking internal combustion chamber. Ugh...sorry had to rant.

Okay, back on topic.

[shatto]

So.....Mark Lawrence says:

Synthetic oils were originally designed for the purpose of having a very pure base oil with excellent properties. By starting from scratch and building up your oil molecules from little pieces, you can pretty much guarantee that every molecule in the oil is just like every other molecule, and therefore the properties are exactly what you designed in, not compromised by impurities from dead cockroach shells or whatever.

**Let us not overlook the fact that lubrication is done by those little molecules.
That is why we now use 20 weight oil and are transitioning to 10 weight and likely 5 weight oil. A definate case of "More is better' being worse because the higher viscosity oil does not get into the smaller nooks and crannies of a modern engine.

AMSOil, Motul 5100, Mobil-1 MX4T, Mobil-1, Redline, and Golden Spectro are apparently made with high quality additive packages, similar to the commercial synthetics. Personally, I would find it reassuring if these oils were CI-4 certified.

**Amsoil often does not meet the various 'certifications' for the simple reason that that certification locks the formula in place, which stops improvement. It costs money to certify, so each change in formula and resultant re-cirtification raises the price.

**The good doctor did his study in 2003. This means that the recently introduced European Formula and the motorcycle oils cannot be judged along with their other lubricants that "meet or exceed' manufacturer requirements.

Pretty good education in the article.

[bowtieguy]

this guy claims to be an expert, but i disagree w/ most of what he recommends...and so do chemical experts and mechanics i've listened/talked to.

http://www.nordicgroup.us/oil.htm#Follow the Money

[FrugalFloyd]

What do you disagree with, and why? Your link's author seems logical and factual to me.