I seen this oil at home depot called “Powermate Non-Detergent 4-Cycle Engine Oil - 10W30” my oil knowledge is at a beginner level but I thought multiweight oils were a emulsion. How do they make a 10w30 oil if there is no detergent in it? heres the link
The presence or absence of detergent is independent of the viscosity specifications. Multi-viscosity oils often use additives (other than detergents) to change the way in which the mixture’s viscosity varies with temperature.
what kind of additives?
So if they are adding a polymer wouldn’t the oil I listed earlier “Powermate Non-Detergent 4-Cycle Engine Oil - 10W30” which is advertised as a petroleum based oil actually be a semi-synthetic oil?
The weights are basically a band of viscosities that an oil has to fall into when measured at a given temperature.
For example an oil listed as a Xw-30 means that at operating temp (100 C), the viscosity falls between 9.3 and 12.5 centistokes. The w number (say… 10 for a 10w-30) has more to do with other measurements like pumping and cranking than it does strict viscosity, but it’s a similar thing.
But, when all’s said and done, a higher spread between the low and high numbers means that the oil doesn’t thicken as much as it cools, which is kind of backwards from how most people conceive of it.
Think of it this way- when the engine’s operating, if it calls for 30 weight oil, you want it to be somewhere between 9.3 and 12.5 centistokes. That’s optimal. What you want then, is an oil that thickens less as it cools, and in general better cold performance equates to a thinner oil.
So you could say that a 5w-30 thickens less than a 10w-30 as it cools down, since they’re both in the same operating band temp.
All that being said, it may just be that the basestock oils used for that particular oil actually meet the 10w and the 30 specifications without viscosity improvers. It’s not at all uncommon for group II and higher base stocks to have performance similar to multigrades without actually being labeled as such.
Oh… synthetic/semi-synthetic has to do with the basestocks, not the additives, so no, adding VI improvers doesn’t change the synthetic/non-synthetic nature of the oil.
This may be a helpful overview of typical motor oil additives.
As for detergents, here’s how it was explained to me once:
If your engine has an oil filter, then you should use an oil that contains detergent. The detergent will cause the particulate contaminants (dirt and whatnot) to be suspended in the oil, which will later be “caught” in the oil filter.
If your engine does *not *have an oil filter, you do *not *want to use an oil that contains detergent. The detergent will cause the contaminants to be suspended in the oil. But because there is no oil filter, the contaminants will *stay *suspended in the oil, and eventually cause wear. Instead, you want to use a detergent-free oil. With a detergent-free oil, the particulate contaminants will simply fall to the bottom of the engine via gravity.
As applied to products you see on the shelf, “synthetic oil” is purely a marketing term.
Synthetic oil is used to suggest “this is a really awesome oil”.
Any number of oils marketed as fully synthetic are actually very, very highly refined conventional oils (called Group III by the industry) with additives. These oils actually perform in line with “true” synthetics.
Here’s a summary by Pat Bedard from Car and Driver:
http://www.caranddriver.com/columns/pat-bedard-synthetic-motor-oil-gets-all-new-semantics-column
All motor oils that you’re ever going to see nowadays have some additives, so by the logic you applied above, everything is at least semi-synthetic. That’s not how the industry chooses to label things, although frankly your thinking makes just as much sense as that of anyone who works for the industry.
Simple way to understand it: Mufti-viscosity oil contains additives which consist of long chains of tightly wound molecules. These chains stay wound tightly together at low temperatures, and begin to ‘unwind’ as the temperature increases. And when they unwind they increase the oil’s ‘thickness’ or viscosity. This is exactly what you want- oil that’s thin & flows easily when it’s cold, then thickens up as the temperature increases.
The greater the viscosity range the more additives you need. Straight 30W oil has none of these molecule chains, it’s always just 30W (so you’d only use it in very hot climates). 10W-40 used to be the most popular viscosity, but in order to get a range of 10 to 40 it required a lot of those molecular-chain additives and too much of them compromises some of oil’s other properties. That’s why it was replaced with 10W-30 about twenty years ago.
I believe true synthetic oils accomplish this without these additives. Consequently they perform even better (but are also much more expensive). Although they’re not a scam, unless you drive in an extremely cold climate synthetic motor oil is not really worth the extra expense.
Based on substantial reading, this is sometimes true.
Absolutely correct.
Even if you DO drive in very cold climates, there are some 0W30 products available that were basically conventional oils. I know that there were a few like this available in Canada 5 years ago… Esso IIRC.
Unless you’re running a trucking line or race team, if your manual doesn’t specifically say “use synthetic” then it’s not a good use of your money.
I remember the first time I saw an oil listed as “0W-something”. I was kind of like, “Huh?! We’ve achieved completely *frictionless *oil?!?” 