bigalbac

I was given a case of Amsoil 10w30 full synthetic motor oil about 10 years ago. Back then, I had no vehicle that used synthetic, but now I have a base 08. Can I use the 10w30 even though the manual recommends 5w30? Bottles say they meet GM4718M spec. If so, any problem with using 10 year old oil? All bottles are sealed-never opened.

enventr

Call up Amsoil they will let you know for sure

Patsgarage

I would have no problem using oil that old, after all it was in the ground for 1,000,000,000,000,000,000 years. I would not use 10w30 if your car calls for 5w30 however.

Bruze

Unless things have changed recently, there are no engines "that use synthetic." Synthetic is a superior lubricant compared to dyno juice and is better for any engine. There is a story about synthetic causing seal and gasket problems, but it is mostly an urban myth I think.

I don't think using 10-30 in your Vette is a big deal, especially if you aren't running it in cold weather. Instead of needing rings at 200,000 miles you may need them in 190,000.

buckmeister2

Hmmmm...I've been using synthetic since '94 or so...guess I was ahead of my time.

Do any of you know when Corvettes started coming off the assembly line with Mobil 1 Synthetic Oil?

Answer will be added tomorrow...

CHEV AGAIN

>>10w30 full synthetic <<

Was never in the ground.

Mark

CadVette

Use it during the summer. The 5W or 10W means the viscosity of the oil during the winter months when it's cold. Ten year old oil in sealed containers will not affect it's ability to be any different as to when it was new in the case. Otherwise you would see an expiration date.

919cw313

1993

When the brainwashing began.

CadVette

Synthetic motor oil is more likely to find a place to leak out of, but it will not cause seal or gasket problems.

LDB

Neither the viscosity nor age give clear yes/no answers. On viscosity, all oil is too thick on startup, which is why you take it easy until the engine warms up. 10W30 is slightly worse than 5W30 in that regard. As one other poster said, if you are in a cold climate, it would make that problem worse. There’s also the more subtle and counterintuitive problem that at very high oil temps such as on the track, 10W30 is slightly thinner than 5W30. That’s because the “10W” vis is measured at 32F while the “30” vis is measured at 212F, so the slope of the line connecting those two points is steeper for an oil with a smaller spread between the two numbers. Since it’s the same at 212F (due to the same, “30” designation), the steeper slope for 10W30 means at temps below 212F, it’s thicker, but at temps above 212F, it’s thinner. Since the difference is small, neither of the vis issues is a killer that means you are in grave danger of ruining your engine, but both are in the wrong direction.

On age, the issue is not the base oil. Whether synthetic or dino, it should be ok for 10 years in a sealed container. The questionable part is the additive package. Those are the anti-oxidants, corrosion inhibitors, pH stabilizers, EP agents (extreme pressure, as in valve lifters or gears), and so forth. Those chemicals are in general, less stable than the base oil. I’ve seen shelf life studies that say they are ok at 2 years, but I’ve never seen any studies as far out as 10 years. So while I can’t say you are in serious danger, you are certainly pushing the envelope beyond where it has been tested.

Bottom line, it depends on how you view risk. Odds of causing a problem are low, but not zero. Savings for using the old oil are small in comparison to the cost if there does turn out to be a problem. I wouldn’t use it in my own engine, but neither would I call you stupid if you decide to use it.

AORoads

1992

Agree w. LDB above re relative risk. Matter of fact, I believe Mobil 1 now states a "shelf life" for unopened cans of oil.

cclive

Just use it in the summer and it will be fine. I wouldn't put it in and then be starting the car in zero degree weather every morning.

windyC6

LOL....hate to open this can of worms, but have to hear the opinions on this one >>> Unless we are talking way down in the 20 - 30 below temp category, is there really enough of a difference in 5-W and 10-W to honestly worry about ? This kinda seems along the lines of back in the day when they said NEVER combine syn and dino or your motor will melt into a big pile of goo. LOL....now you can buy them already mixed....whod a thunk it.

RagTop69

Contact Amsoil to insure the oil is OK to use at 10 years old (I'm betting the answer is yes) and then find a friend with a car that uses 10W-30 and have him buy you an equal number of quarts of Mobil 1 5W-30. Make the trade and he gets a better price on the Amsoil than he would normally and you get the oil prescribed for your car.

The smaller molecular structure of full synthetic oil allows it to get into places that a dyno oil can't, including close tolerance bearings and potential leaky gaskets. I have a '69 Mustang that has the original 302 in it and I'm not planning to switch from my good old Castrol 10W-30 dinosaur oil. I also kept my '69 Corvette 427 on 10W-30 Castrol. All of my newer cars over the last 20 years, however, had 5W-30 recommended and (with the exception of a brief romance with Redline in my LS1) I ran Mobil 1 in all of them. That included four different 4.3L Safari vans('95, '98, '01, '04), a'97 LT1 Camaro, a '00 LS1 Camaro and a '13 Nissan Altima 3.5L.

Red08

That would be a great question for Ask Tadge. How do they determine which oil viscosity is best? What can happen if the viscosity used is different than what GM recommends? In fact, I just may ask that question given the vast number of question of the forum related to engine oil

LDB

I could respond to that two ways. One way is to agree that 10W30 isn’t likely to ruin your engine. But the LOL kind of annoys me, as though no intelligent person could conceivably think it even remotely mattered. So the other way I could answer is to quote actual viscosities in centistokes, which gives a much truer indication of the actual oil thickness and thus how easily the oil flows than the SAE numbers that appear on containers of oil. You can then judge how loud your out loud laughing should be.

When hot at 212F, both grades are about 12 centistokes. At 90F, 10W30 is about 90 centistokes while 5W30 is about 60. At 60F those numbers are about 170 versus 100. At 32F, the numbers are about 370 versus 190. At 0F, the numbers are about 1200 versus 450.

The fact that there are substantial differences in the oil thickness during the warm up period doesn’t translate in direct proportion to rate of bearing or ring wear. Even thick oil is a pretty good lubricant. The point is, viscosity increases exponentially as temperature falls, so the actual viscosity difference for closely spaced SAE grades is bigger than the SAE numbers would lead you to believe, especially at low temperatures. So while I agree it isn't a killer issue in a moderate climate assuming gentle driving during warmup, I wouldn't laugh it off either.

windyC6

Well thats too bad that the LOL annoys you. You are correct, that is basically what it was meant to mean. We sometimes seem to want to go over board with all of our analyzing and use of super figures and words in an attempt to thump our chest or try and prove our intellectual superiority in certain fields when it comes to all this mechanical wonders stuff. If someone wants to lay out several paragraphs on why using 5 weight instead of 10 weight could be detrimental to ones engine, then so be it and they should be proud of their knowledge on the subject. As for me, engineering Einstein i'm not, but I got no problem using 5 weight instead of 10 weight because I know that in the real world the differences are minuscule and really not worth mentioning .....

HOXXOH

Since you posted a question, it indicates you have fears/concerns and are in need of advice to either go boldly forward of bail out now.

If after you've heard all the pros/cons and are still undecided, a solution to use 3 quarts of old and 3 quarts of new, might make it easier. Of course you might consider giving out a quart or 2 of oil as Christmas presents to several friends. You know a little bit certainly won't hurt whatever they put it in.

buckmeister2

Correctomundo, AO...it was 1992.

buckmeister2

Windy6,
After reviewing the article on the Amsoil page (http://www.upmpg.com/tech_articles/motoroil_viscosity/), it appears that each 5W increment lower results in about 9 degrees (F) better protection. 0W gives you the same "pumping max" pressure at -22 degrees(F)--that is 22 degrees below 0--that 5W gives you at -13 degrees.

FWIW, if you live in one of those extremely cold environments where -22 or lower occurs with regularity, you should be using 0W-15W during that time period (however, the 15W may not give much protection to an engine that gets heated to 210degrees) For every 9 degrees above -22, you can use the next-higher rating. For me, living in Las Vegas, we rarely get below 30 degrees (F), so even 30W is a sufficiently-low number. Still, I use 10W-30W because it gives me better flow at startup, and still maintains 30W viscosity at 210 degrees.

Now, if you understood that, please explain it back to me, because I am not sure about it....

So, yes, ?Windy6, it does make a diff if you are in a very cold climate.