I've "heard" that about 30% is typical.

Search the link below-

Here is a link that might be useful: BITOG

I fial to see much point in "Synthetic Blends" versus full synthetics. It's like buying Caffeine Free Diet Coke in my opinion. :)

I have to agree w/ c-tobio, why bother with blends. Just go with full synthetic. The engine will run cooler & it provides better lubrication.

That's the thing I don't get. Sure, it's a buck or two less a quart, but a) how much synth vs conventional content is there and b) is it worth the savings to not get the full benefit from a full synthetic.

I change my oil every 3000 miles and i know all the facts about you don't have to do it that often but I'm not going to change that habit. i use partial synthetic for one reason . It flows better than conventional oil in sub zero weather. if you don't believe that take a quart of dino oil and partial synthetic and pour them when it's 15 or twenty below zero. My oil changing habit makes full synthetic too expensive to use every 3000 miles (which can come every 3 or 4 weeks) but I get the benefit of easier startup and less engine wear at start up in the winter time.

ctpuritan- I can't remember the last time we had sub-zero weather here in CT, so the 15 degrees below zero test would be kind of hard for me to replicate. :)

Anyway, you are correct, synthetics pour better at lower temps- pour point is -54F for Mobil 1 5W-30m, while Mobil Clean 5000 5W-30's pour point is -33F. Most of us would not be testing this specification out.

You'll certainly do no harm, except to your wallet, changing your oil "too often".

It's been several years since I saw a "dissertation" on the synthetic% in a blend, but it was pretty obvious that one could "mix their own" for noticeably less money.
IIRC, the 30% "seems" right, but my memory isn't fool proof for sure. It might have been a bit less%????

I don't really see much difference in the argument of "real" vs "blend" than "real" vs "dino". How about "dino" vs "blend"?
Maybe the "blend" people are just trying to get along:-)

constantinotobio: I came from your neck of the woods(New Haven)to northeast CT about 37 years ago. i agree you do not see below zero weather very often. My personal low since i have lived here was -28 fahrenheit. Despite our recent mild winter the previous winter's low was -14. I also spend some periods of time in Northern VT in the winter where I have experienced -40 temps. I think I get some benefit from the blend and think my changing my oil frequently benefits the extended mileage i get on my cars. My wife's 1997 4cyl, bottom of the line, ford escort has 223000 miles on it and continues to have excellent compression. I run 4 vehicles in my household and they all reach the 200k mark or better.

You guys might be having an interesting discussion, but you haven't addressed Hercules' question. He wasn't asking what you think of blended oils. His question was, among oils that are labelled synthetic (not synthetic blend), how can you know whether they are pure synthetic? And if they are not pure synthetic, how do you know what percentage synthetic they are?

Bill in Orygun,

Thanks for the link. That's huge site....perhaps I can find an answer there. Thanks, too, for not giving me a lecture. ~grin~

Hal in Pennsyltucky

A big factor in oil change habits to consider is "How long is the average drive distance / run time, after the cold start-up"? The engine lube oil is subject to contamination from water and fuel wash-down (in the blow by gases) mostly in the time period from "cold start-up" to "normal operating temperature". If the engine is run for a significant distance / hours after start-up before being shut down, you can increase the mileage/hours between your oil changes, affording the owner a real benefit in $ saved without compromising the health of the engine. This could allow an owner to use a higher price per quart "Full synthetic oil" and still keep the "cost per mile/hour" about the same as using "cheaper" oil and changing more often. Example: Big, highway trucks will typically start up and travel 500 miles/10 hours in a trip (or even more with multiple drivers). These truck engines are using the same basic oil as your passenger cars (or garden tractors etc.) Most truck owners/companies change the oil in these engines at 25,000-30,000 mile intervals. These truck engines operating on this maintenance schedule will achieve lifetime accumulated mileages from 800,000 to 1.4 million miles (typically). If anyone "wants" to change the oil more often, they certainly have that right. If you operate your engine on short trips/short run times, you should change the oil more often. If you operate your engine on long trips/long run times, you can increase the interval between oil changes without fear or guilt. Please note that persons operating commercial lawn maintenance equipment that transport equipment to several sites in a day's work period, should change the oil often because of the multiple cold start-ups (and increased oil break down from blow by contamination these engines will be exposed to). This was just "food for thought" and I'm not judging anyone's personal maintenance practices.

montessa vr: My discussion with constinonobia put aside you need to read the original post again. The writer was asking specifically about the percentage of synthetic oil in blends and claims of superiority by manufacturers. He wasn't talking about full synthetics. I noted that one plus "blends" have over Dino is flowability in very cold weather and that is why I use it. As to individual formula's for synthetic blends I don't have that info and it hasn't shown up here up to this point.

ctpuritan,

Thanks. You are correct, of course. I didn't address montesa's post, for his basic point was that (except for two of you) most posters were not attempting to answer my question at all. I appreciated his intervention on that.

Not so very long ago a guy could ask a question on this forum and get a straight answer, even if it was "I'm not sure" or "try this". What's happened here? Now it seems that pontification is the norm. And that's a shame.

Thanks again for your post, ctpuritan. I really appreciate it, and will post back if I find the answer to my original curiosity question. That's how we used to share info on this forum, and is what made this forum so valuable.

BTW, I agree with your attention to detail with your maintenance schedules. Machine/vehicle longevity is money in the bank. You go, guy!!

Peace,

Hal

hercules, I see a problem with your question.

As I understand oils, None of the latest oils are natural. They could all be considered synthetic. They are all cracked (modified) after being pumped out of the ground. 50 (100?) years ago oil was pumped out of the ground and then distilled by its boiling point. Thicker oils boil at higher temperatures.

I have read that Amsoil and Mobil 1 oil is a PAO (type 4). Castrol (and most other synthetics) are type 3 hydrocracked. I think esters are type 5, but I don't know where they are used.

So most blends would seem to be a mix of cracked and hydrocracked. Mobil 1 should be a mix of cracked and PAO's. So I would think the question should be what type of oil AND what percentage.
I am not sure that it even matters which base is used. Perhaps we should look at the approvals on the back label. While the SL (and SM) oils have better testing and improved refineing to meet the testing, I have read that euopean standards are even tougher.

BTW.. I saw the evidence that mobil 1 was way better than valvaline 25 years ago. But then in 1990, mobil had a new formulation. then they came out with a new version in the late 90's. And now they are on their 2nd or 3rd version of supersynth. Other (conventional) oils have changed just as much, or maybe more.

Oh, As to mobil 1 pouring easier than valvoline, we had a winter in 1983 (dec) that had many mornings below -30. I took jars of 5w-30 outside and tipped them over several mornings. Both 5w-30 oils (valvoline and mobil 1) poured about the same. But of course they do, that what the 5w-xx means! The mobil 1 looked like a smooth honey. The valvoline looked awful, that would be cloudy and even chunky. I also had a 10-30, but it set up and wouldn't pour at all when turned over, hence its thicker rateing.

Further, In the car the valvoline broke down under pressure to be thinner much faster and let the oil pressure go down much faster than mobil 1. So mobil 1 gave higher oil pressure for longer. The valvoline reminded me of jello, poor flow, but little resistance to pressure.

JerryO

My goodness. What a cerebral treatise on synthetic oil!

However, I suspect its validity depends upon what your definition of the word "is" is.