That's exactly what I was alluding to--not necessarily M1 being the 'best', it's what GM provides for our oil changes. I'm not brand-specific and have used various synthetic oils in the past.
(And BTW, what is this mobilE 1? )

 

Sorry, my fingers got ahead of the brain. (Happens more and more lately.)

Factory oil on mine was light yellow gold.

 

Speaking of Mobil 1...

This evening I was at the local BJ's and they have Mobil 1 on sale. Depending on the blend it's going for 26.99 or 27.99 per 6-pack; which not bad at all. The have 5-20, 5-30, 10-30 and I belive 0-20.

There is a 3 case limit, but that's easily gotten around.

I live in South Jersey so other areas may not have the same offer.

 

I use Castrol, but that's because I dislike ExxonMobil as a company. Yes I know Castrol is BP.

Anyway, GM has to give everything a fancy marketing name, the average customer doesn't understand what "Meets or Exceeds GM 45234566" (insert random number for some GM spec)

 

Please post a copy of your degree in petroleum engineering if you hate Dexos.

 

I had a longer, more technical post up for an hour or so, but deleted it as being too much. Instead, I’d make the following points. First, I agree that there are no longer any oils with 100% of what used to be called synthetics, namely group 4 (poly alpha olefin) and 5 (ester) base stock. But while the lawsuit allowed group 3 base oil to be called full synthetic, it did not ruin synthetic oil, nor does it mean that there are no longer any group 4 or 5 synthetics in today’s oil. While some full synthetics are indeed all group 3, many like Mobil 1 and Amsoil are blends of group 3 and 4, while others like Redline are blends of group 3 and 5. And group 3 is by no stretch bad. With the ultra-severe processing it gets, it’s more like 90% of the distance between group 2 “Dino” oil and groups 4 or 5. Realistically, today’s additives are enough better that even a pure group 3 full synthetic today is probably better than the pure group 4 or 5 synthetics of 10 years ago. In contrast, a synthetic blend, minimum spec Dexos oil is 50% dino oil and 50% group 3 synthetic, so that makes it about half way between dino and group 4 or 5. That’s still not a bad oil, and as many have said, under all but the very most severe driving conditions, you will not have any oil related engine problems with minimum Dexos spec, synthetic blend. Even dino oil isn’t terrible with today’s additives. True, it has some low quality aromatics and sulfur, but the levels are not killers for routine use.

Pennzoil Platinum is a special case, essentially equal to group 4. Group 4 is a poly alpha olefin, man-made from ethylene, while Pennzoil Platinum is an isoparaffin, man-made from natural gas. But the poly alpha olefins in group 4 are hydrotreated to isoparaffins before going into lube, so they are very close to the same thing (slightly different isoparaffinic structure, but both excellent lube base stock), simply generated by different man-made routes. I do not know whether Pennzoil Platinum also has some group 3 base stock. If it doesn’t you could argue it has the best base stock of all, because it wouldn’t have even the small quantity of naphthenes that group 3 oils contain.

 

Good post. You actually know what you are talking about as opposed to some posters on this thread. I currently use Penzoil Platinum Ultra in my 2014 Ram. Hard to find but worth it. May switch to that for my next C7 oil change.

 

Dealer put Kodexos in my 2014 Z51. Saw Dexos on my receipt when I got home. Took it back the next day and got a free oil change with Mobil 1. Hope he did not spit in my oil. Explained Mobil One only for dry sump Z51. "I don't need no stink'in Dexos."

 

Never meant to imply group 3 is necessarily "bad." But most people don't understand what "Full Synthetic" does and doesn't mean any more.

The truth is that all of today's high quality oils offer excellent protection. Mobil 1 isn't the best oil you can buy, and if you run Dexos blend in your car, and change the oil when needed, the rest of your car will wear out before the engine. But to read this forum you'd think Mobil 1 some magic elixir that will eliminate engine wear where a "synthetic" blend is evil and your engine will burn up if you use it.

All of them meet GM requirements.

 

Thanks, always appreciate your posts on oil. Nice to see an expert provide accurate info to put the oil "issue" in perspective.

 

Is Mobil 1 15w50 a group 4 or 5? I've heard that 15w50 has more zddp and therefore better wear properties.

I'm no expert, just repeating a few things I've heard.

 

First, thanks in return to Jerry U and BladeSilver.

As far as this question, I didn’t work for Exxon/Mobil, so don’t have insider knowledge of their formulations. Last time I talked to someone who did was about 4 years ago, and at that time, all Mobil 1 auto varieties were blends of groups 3 and 4. Only a few of their specialty products for aviation were pure group 4. Nothing I've seen suggests anything has changed since then, but I don't know for certain. As far as group 5, not many oils use it. While there are probably others, only Redline comes immediately to my mind. Group 5 is a tradeoff. It has some good points, but also some bad. I don’t want to get into that debate.

Comparing ZDDP to other EP (extreme pressure) additives is somewhat like comparing group 3 to groups 4 or 5 synthetics. Yes, ZDDP is very good, but just like allowing group 3 under the full synthetic label didn’t ruin full synthetics, limiting ZDDP didn’t ruin EP additive effectiveness. So unless you are running a high lift, flat tappet cam at high RPM with extreme valve springs, I don’t think you should worry much about it.

The other thing I’d mention is that unless you are on the track, 15W-50 would be a fairly serious mistake, too heavy both for cold starts and street driving. It also has the disadvantage that with that wide a spread between W and normal number, it would need to use VI improver additive, which is among the least stable of the additives. When you get right down to it, the biggest single advantage of synthetics is higher base oil VI. The natural spread of a full synthetic is about 25, so for example, you can make 5W30 or 15W40 full synthetic without VI improver additive. Going over 25 requires VI improver even with a full synthetic. The natural spread of dino oil is zero, so any multi grade dino oil needs quite a bit of VI improver additive.

 

Thank you for a great explanation.

I run 15w50 for warranty reasons on the track and at auto crosses. Do you risk damage for street use or is it just not ideal for non-stressed driving?

I owe you a beer for all this great info!

 

I wouldn't run 15w50 for autocross. The runs just aren't long enough to heat the oil to the point where you'd need that. In fact, if you're shutting the engine off between runs, you're probably harming your engine, because the oil won't get and stay hot enough.

 

Just saying autocross doesn’t really tell me how heavily you are using your engine, but Meyerweb may be right, 15W50 may be overkill for you. The key is oil temperature, so set your instrument readouts on that, and see what it runs during your autocrosses. If your oil temp never goes above 250 or 260, you are ok with 5W30. Track use, where 15W50 is recommended, will send it to the upper 200’s for extended periods of time. Obviously there’s a lot of gray area in between those two. If it’s just an occasional burst of a few minutes here and there into the upper middle 200’s, I’d still stick with 5W30. A possible compromise if you are in the middle of the gray zone is 5W40. You could get by on that ok on the street without too much risk. The trouble with 15W50 is that it’s clearly too heavy for street use, so you’d be in the dilemma of wondering whether to change your oil back and forth all the time.

The underlying problem is that you want your oil viscosity at running temperature to be in the range of about 7 to 15 centistokes. With 5W30, that corresponding temperature range is about 170-250. With 15W50, it is about 230-300. So on the track with heavy engine use, you will be above the upper limit on 5W30, but on the street, you will be below the lower limit on 15W50. Unfortunately, the word “limit” in this case is a relative term. It’s not as though a few degrees inside the limit are perfectly ok, and a few degrees outside the limit are disaster. There are gray areas in life that you have to deal with, and this is one of them.

 

I've have seen and often contemplated a synthetic straight 40 oil. A GM field engineer turned me on to the possibility but he quickly reminded me that 15w50 was recommended for track use and would be looked at if warranty were to become an issue.

The autocrosses yield mid 200 temps pretty regularly. The tracks bring out upper 200's. I don't shut the car off between runs because I like to get the coolant back down under 230 after a run.

 

I don’t think there is such a thing as straight 40 weight full synthetic. A full synthetic should have a natural spread of at least 20, and really more like 25 even without VI improver. So it ought to be at least 20W40, if not 15W40. If it’s truly a straight 40 weight, I’d have to wonder if it’s really dino oil using some creative definition of synthetic. A better compromise in my view would be 5W40. That way you wouldn’t have to worry so much about taking it easy during warm up. The down side is that it would use some VI improver additive, so might be a bit iffy to take all the way to 10000 miles. But with conservative change intervals, it should be fine.

 

[QUOTE=LDB;1591023345]I don’t think there is such a thing as straight 40 weight full synthetic. QUOTE]


I think you are right. In fact, the only synthetic straight weight oil I know of is Amsoil Synthetic 4-Stroke Small Engine Oil. It is rated as a 10W-30/SAE 30 Grade Oil. Fantastic stuff by the way. Use it in all my small engines (whole house generator, pressure washer, etc.).


I would be interested to know if anyone else knows of any other synthetic straight weight oils.

 

According to the Amsoil site, that oil meets both 10W30 and straight 30 specs. But any multigrade with the last number of 30 will meet straight 30 specs, so that’s not saying much. The old straight weights were all measured at 100C (212F), but the W grades are measured around 32F, the exact temp depending on W grade. All multi grades ending in 30, as well as straight 30 are about 12 centistokes at 212F. But at 32F, straight 30 is about 2500 centistokes, 10W30 is about 400 centistokes, 5W30 is about 150 centistokes, and 0W30 is about 70 centistokes. All are thicker than ideal at startup temp on a cold morning, but you’re obviously less bad off with one of the W grades than with straight 30.

When you talk about VI (viscosity index), the higher the VI, the less the viscosity changes with temperature. Multi grade oils have higher VI than straight weight oils, which means their viscosity doesn’t change as much with temperature. Before synthetics, there were only two ways to make multi grade oil. Almost all of it was made using VI improver additives. A small amount was made from ultra high quality crude oil from an oddball region in Pennsylvania, which is where the names Pennzoil and Quaker State came from. But almost all of that crude is gone now, so even those brands now must use VI improver in their multi grade dino oil. Synthetic components have higher VI, so you can make multi grade oil from them without VI improver.

With that background, the only reason I can think of for Amsoil to call their oil 10W30/SAE30 relates to the high temps in air cooled engines. That is very hard on VI improver, and VI improver isn’t all that stable even under ideal conditions. So you don’t want a multi grade dino oil with VI improver in an air cooled engine. If/when the VI improver degrades, then dino oil degrades to the viscosity of the W number, so for example, 10W30 would degrade to straight 10. Perhaps Amsoil means to imply that their oil has no VI improver, but that’s a pretty meaningless claim. No 10W30 full synthetic would need VI improver. Anyway, bottom line is that for your air cooled stuff, you should either use straight weight dino oil, or multi grade full synthetic with no more than a 25 spread. That way, you won’t be getting any VI improver.

 

[QUOTE=BladeSilver2015;1591025251]Yup, I messed that one up. It's 0W40 not 40.

Mobil 1 0W40