"What do the numbers on motor oil mean?"
By Steven Fletcher
"In the old days, oil was oil. Not so today.
What do the numbers and letters in a motor oil designation mean? Good question. Here's the answer.
First, there's a two-letter code indicating the type of detergent package that the manufacturer uses in the oil; this looks like SE, SF, CD or such. The S codes are for gasoline engine applications; the C codes are for diesel engine applications. The second letter is assigned in sequence as new levels of protection are developed; thus SF is considered better than SE, SE is considered better than SD, and so forth.
The more noticeable designation is the oil weight. This is either a single number (e.g., 30 weight) or a pair of numbers separated by the letter W (e.g., 10W30.) The latter type is much more commonly used these days, and are the only type that most automobile manufacturers specify in operators manuals. The first number in the designation (10W) is the apparent viscosity of the oil when it is cold; the W stands for `winter'. The second number (30) is the viscosity of the oil when hot.
There is a trick here; the oil doesn't actually get thicker (turn from 10 weight to 30 weight) as it gets hotter. What is actually happening is that when the oil is cold, it has the viscosity of a cold 10 weight oil. as it gets hotter, it doesn't get thin as fast as a 10W oil would; by the time it is up to temperature, it has the viscosity of a hot 30 weight oil.
Note that these numbers actually specify ranges of viscosities; not all 10W oils have exactly the same viscosity when cold, and not all 30 weight oils have the same viscosity when hot."
Now this I found interesting:
"Also the behavior of multi-grade oils is caused by additives, and it has been reported that some 10W40 oils do not retain their multi-grade characteristics well over time. But 10W30, 15W40, and 20W50 oils work fine."
From: http://rvtravel.com/publish/oil.shtml
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Today:
First thing, Ray painted the other side of the insert to the Grooming Room door. We wanted it to be dry enough to put it back together today. I didn't wanted to leave the foster cats locked up in their cages all night, so they were loose in the house. With the insert out of the door, they couldn't be contained in the Grooming Room last night.
So Prime slept in her favorite place on the back of the couch and Patches on the back of the recliner. (She moved before I could take a picture of her.)
I don't know why I put them to bed in the Grooming Room. Force of habit, I guess.
I have had some wild foster cats who loved to climb on shelves and knock knickknacks down, but these two don't. So my crystal glassware is held down with museum gel!!They get along with Paco, too, so no ruckuses there.
But with the painting going on, they were locked up in their cages this morning, until we had the door back together.
While the paint brush was wet, Ray painted the Dutch Doors between the Middle Room and the Grooming Room. It had been scratched up by boarders.
As all that was drying, we looked at a place on my front door that didn't look right, so we took that 9-light insert out and re-installed it properly, so I could put the clean lace curtains back up.
The City Hall of Cut and Shoot, Texas
Kenya was supposed to come by, but it was storming over in Cut 'N Shoot, where she lives, so it was postponed.
http://www.earlytexasfamilies.com/towns/cutnshoot/index.html
Then the rains came here. We really needed a taller ladder to re-install the cornices, which I had taken down, washed and pressed. But there was no sense in dragging in a wet ladder, so that got postponed, too.
After the rain, it was so much cooler that the cats could go out on the screen porch for the second time today.
Often, in the afternoons, Patches has sat at that door asking to go out there, but it was just too hot, until today.
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