I ran across some information on the manner of identifying oil weights, or at least means of classifying weights. It seemed in the early 1990's or their about there was some studies on oil recommendations that specified that the Viscosity Weight of the oil would be redefined to be a recommended minimum weight. For a variety of reasons but much of it due to the emphasis at the time of improving Café fuel economy largely for some (at the time) government edict or another.
While there is an element of truth to improved fuel economy as a function lighter engine oil in the real world it is difficult to measure any relative results. And if any and done incorrectly, engine reliability becomes a serious problem.
Fast forward another 10 years there were additional studies done to ascertain the extent of engine reliability and initial tests using recommended oil viscosities of that time such as the 5W20 Oil early (and maybe all I am not sure) but early Saturns anyway were OEM specified to run. There were unable to establish initially a base line for comparison purposes as engine failures existed to the point where the compression rings were to become stuck in the lands and oil consumption increased drastically with early on engine failure as a direct result.
And low and behold, that is the reputation that early Saturns had.
As this was in part at the time I was chasing things down only a small part of what I was looking for I lost all references to where I was looking at the time. But did note while scanning the information that the early on results of being unable to establish a base line lead to further re-defining of engine oil viscosity not only by definition but by formula also.
There are an awful lot of what I would call a "TOO" light weight oil being specified for use in a variety of climates that range from below zero F or for that matter Zero C too and temperatures of 212F or 100C as multi-weight oils kick in heavier weight characteristics for heavy duty work or working in high temperature ambient environments, but apparently todays oils are better suited for the job then they were in the period of the early 1990's
A lot was said about Multi-(viscosity) vs Mono-(viscosity) as a comparison. It seems that oil technology like everything else has gotten pretty high tech in the last couple of decades. And of course the variations in performance of synthetics and the way's the chemistry of them can be varied.
A whole lot different then when I first started to drive and it was simple. You ran straight 20W detergent during the winter and straight 30W detergent during the summer and detergent vs non-detergent kept the gunk cleaned out of the engine and deposited into the oil filter. In an era where an oil filter was an option on a number of engines.
It was interesting and needs further research to follow the thread a little closer but for the first time I actually read some positive information as to why early Saturns, a vehicle designed wholly by General Motors a company that has been no slouch at the time in designing some of the best cars and engines in the world. Why that engine seemed to go so wrong if the Factory recommended oil was used during it's life time.
And many of us have fed the things at least something like a 10W30 and had wonderful reliability for a minimum of 100,000 miles.
At least mine has been that way.
Of course a lot of sitting has been done lately and I discovered today that the head lights would not open. I think the contacts in the steering column switch have become oxidized and are making poor contact.
Another project for my round tuit list.

 

Nice write up, Unc. Good luck with the headlights. I hope Val is continuing to improve and recover from her transplant surgery.

 

My car is one of the last S-series to be made (2002), and the oil cap says 10W30 on it. I suppose I should be feeding it synthetic to get the best protection for such a high mileage engine (200k). But, dino oil has worked just fine, and dino oil is still cheap per bottle. I'll keep feeding it dino oil because it seems happy with it.

Anyone run synthetic? Tangible benefits? Still consuming oil?

 

consumes less oil but costs more so which one matters more? Neither

 

As automobiles are my hobby along with a necessity as required by the demands of life I have played "car" for years. And at the moment have a fleet I guess that is genuine overkill.
I have Synthetic oil in my Chrysler (which I just wrecked this week - don't ask!) with 114,000 miles on it and while I think synthetic oils are the premium oils of the era at the moment I do not run them on anything that I did not start out that way with. Running an acceptable weight oil as determined by the Oil weight vs ambient temperature charts seems to give acceptable performance and also did so when I was in charge of a fleet of mixed vehicles run in an environment where triple digit temperatures were often seen. And this was using dinosaur sourced oil. Having run a few engines up into close to 300,00 miles with no problems I personally believe either oil works about the same when regular recommended oil change intervals are followed. And keeping in mind, Mobil 1 which I use is recommended to change the oil filter at a given interval and add the amount of oil lost with the change and there is a recommended mileage interval you change everything and when that is followed the cost of using Synthetics vs dinosaur oil is almost exactly the same.
As I have not had an engine consuming oil since 1976 when I left the snow belt and started living in the SW I agree if consuming oil it costs more to feed an engine synthetics. but I have not had an oil consuming engine (yet).
I am assuming the recommendations of all synthetic oils are similar. And there are a lot more of them then there were when I started using Mobil 1.
Interesting that the last of the SC series engines have a 10W30 oil cap on them. I did not know that.
My Chrysler (a 2007) and my Saturn (a 1994) both have a 5W20 recommendation which I personally have ignored from the day I purchased them.
Now if the insurance people will put my Chrysler back together I will be thrilled. The adjuster will be by today about 10:30. Whoopy-ding. And it is my birthday.

 

Happy Bday, UNC! Hopefully the adjuster will give you what you want for your birthday.

I think you mean 5W30 not 5W 20 for the 94 Saturn.

Interestingly, the way they achieve the higher viscosity oils today (10W40l and above) involves starting with a lower viscosity base mixture, then tossing in a bunch of additives to ensure the viscosity vs temp behavior is correct for the oil weight in question.

The potential problem is that the additives may begin to break down, esp the ones that maintain desired viscosity at elevated temperatures, leading to you essentially putting in say 20W50 and, as time passes, having it change effectively from a 20W50 to the equivalent of a 10W40 or 10W30 based on the overall usage type and environmental conditions. This is especially true for today's synthetics.

I'm not saying this is universally true today. I'm not saying dino oil behaved that way back in the days before all these additives were developed as the formulations were different and I believe the visc vs temp profiles were obtained differently back then.

I'm just saying it can happen with anything 10W40 and above in today's oil landscape.

This all comes from an article I read about six months ago. I will try to find and post the link.

 

[QUOTE=derf;52370]Happy Bday, UNC! Hopefully the adjuster will give you what you want for your birthday.

I think you mean 5W30 not 5W 20 for the 94 Saturn.

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Nope I mean 5W20.
Both my Saturn and my 2007 Chrysler clearly states to use 5W20 motor oil on the oil fill cap. And when I bought my Chrysler I went to the optional "take care of your new car" seminar that was offered and when I raised the question of synthetics I was clearly told that would violate the terms of the factory warranty.

So when I got the car home I decided that that violating the warranty was safer than using an oil recommendation that stood the chance of wearing the engine out as it was common pretty much after WWII at 100K oil consumption was about equivalent of that of the alcohol of a drunken sailor (something I was some what accustom to as being a sailor) I immediately changed to oil to 15W50 Mobil 1 synthetic and never bothered to tell them.

And yup the adjuster said the fixing my Chrysler was a financially responsible decision. (Happy dance) and it will go to Bill Luke , the Chrysler dealer where I bought the thing.
Costs will be my 500 deductible and the about $400.00 ticket I got for having the accident.

And oh yuh
Merry Christmas

 

Derf
I think that from what little I have read recently on oil formulation that there are a number of things going on in the chemistry as to Viscosity is determined both short and long term.
The concept of an average thickness or viscosity as it act and how temperature ranges effect things, cold starts vs hot environments.
And add to that F.I. is pretty much a start and drive mode of operation where a carbureted car needed to be warned up before it ran worth a darn. (A problem when a today's hobbyist restores a carbureted car and then is disappointed in how it runs until it gets warm.
Also you have todays Computer assisted machining which can and does not only hold tighter tolerances part to part but has the capability of manufacturing complex parts that were not available years ago.
For example and just one of them, many if not most engines including all number of cylinders are 2 bolt mains, a 4 bolt main engine is considered unusual and generally applied to heavy duty usage motors racing and performance specifically but todays LS1 Chevy V8 has 6 bolt mains which when assembled makes a pretty tuff block assembly yet that engine in not only a performance engine but found in trucks.
A performance engine in the distant past would or could or did use ball or roller bearing main bearings and the offy 4 cylinder engine the main bearing assembly was installed with an interference fit by heating the block as the crank was installed with the main bearing holders assembled on the crank shaft.

Obviously it was a marvel in precision manufacturing at the time, but it was assembled with an acetylene torch applied to the block to expand the bearing holders so things fit. A production technique not adaptable to mass production.

And todays motors use adjustable cam shaft timing which is a method known for shifting performance rpm around but only when installing a cam leading or trailing a bit. Todays taxi cab motors do that automatically now using oil pressure. A function in part of the viscosity of the oil of course which places new demands on things.

The subject becomes fraught with variables!

 

I wholly agree that there are many variables that may come into play when trying to evaluate the performance of today's additive rich oils. My comment was directed at the overall outcome of those interacting variables MAY be a significant decrease in oil viscosity (behavior and property wise)/for the higher weight oils vs those oils with less additives.

I am in no way implying that every crankcase full of 20W50 turns into 10W30 in 300 mi. I'm simply pointing out that, based on current formulation techniques, this behavior MAY be seen. You are quite correct in noting that a zillion variables will affect the oil's behavior as a function of time, temperature, etc. I was simply trying to broadly describe a single well known phenomenon that is known to occur.

 

Happy Belated Birthday, John. Did you go out and party? Get s*%t face drunk and pick up a prostitute? Wait a minute, I'm thinking about goalieo. Never mind. LOL