Originally Posted by GCoupe35

The initial guy told me that they dont use 5w-30 anymore because it gets too hot in Texas so they switched to 10w30. IS this correct or should I have stuck with the 5w30?

Originally Posted by tonke73

I've never used Chevron motor oil so i can't comment on that. 5w means the viscosity of the oil when cold. 'W' means winter. 30 is the viscosity of the oil at 100 degrees centrigade at operating temperature. 5w30 flows better when cold and flows (same viscosity) the same as 10w30 when at operating temperature.

They'll be plenty to chime in and correct me if i'm wrong. I personally use 5w30 in my G.

Originally Posted by GCoupe35

I will wait 3 months, I have 15k miles right now...Ill prob go Mobil 1 Syn 5w30 next change with the OEM oil filter....

I dont know if I can trust Infiniti anymore either.... I wont be going to the dealerships anymore which I always did more my oil changes =(

Originally Posted by tailwindK

Never go to the stealership for an oil change! I pay about $68 for Mobil 1 syn 5w30 for my G(not super cheap, but I dont have my ramps currently to change it myself). Usually run it for 5-6k before I change it. No problems at all, no oil loss really, and my G runs really smooth. Hope any of that helps.

Originally Posted by Resolute

What does the oil weight actually mean?
An oil’s weight refers to it’s measured viscosity at a given temperature. The temperature of the oil is important when measuring it’s viscosity because an oil becomes thinner, or less viscous, when it is heated. Conversely, oil becomes thicker, or more viscous, when it is cooled. Because oil viscosity changes with temperature, an oil’s weight is determined by the measured viscosity at a specific temperature (100 deg C). The unit of measure is called a centistroke (cSt). The higher the measure of viscosity at 100 deg C in centistrokes (cSt), the higher the oil’s weight. The following chart shows the viscosity an oil must be at a given temperature for each oil weight.


So how does that translate into the weight I see printed on the bottle, like 10W-30?
Some oils are straight weight oils, like a straight 30 weight oil. This means the oil is always a 30 weight oil at any given temperature. The oil still thins out with heat, and thickens up as it cools, but at any given temperature it will measure within the specs for a 30 weight oil at that temperature. This is not good for your engine during cold starts or in cold weather, because a 30 weight oil is very thick when it is cold. Thick oils are harder to pump and therefore don’t flow through the engine and lubricate very quickly. The solution is a multi-grade oil. A multi-grade oil is still thicker when it is cold than when hot, but not as thick as a straight weight oil. In the case of a 10W-30, the “10” refers to the oil’s “Winter” weight (hence the “W”). A 10 weight oil is thinner than a 30 weight oil at cold temperatures, and thereby flows easier to properly lubricate the engine upon start-up. As the engine reaches operating temperature, the oil thins out- but does not stay a 10 weight oil. It becomes a heavier weight, and in this case, becomes only as thin as a 30 weight oil at operating temperature. Here is a simple chart, courtesy of Noria, that shows how a 10W-30 compares to straight 10 and 30 weight oils.


What winter weight should I use, a 5W, 10W.. etc?
Since the majority of engine wear occurs during start-up, it is important to use oil that will flow well and lubricate the engine quickly during this time. Remembering that oil is thicker when cold, the proper winter weight is one which provides the maximum amount of flow for the given ambient temperatures when the engine is started. The colder the temperature of the oil, the harder it is to pump, so a thinner winter weight is beneficial during start-up. As ambient temperatures increase, the oil will thin out and start to get closer to its operating grade, and at some point, multi-grade oils like 5W-30 and 10W-30 will be close to the same viscosity for a given ambient temperature. This means that there is no harm in using 5W oil even in hot climates. As an example, the start-up viscosity of a 5W-40 and a 15W-40 may well be the same if the ambient temperature is hot enough. This also means that heavier winter weight oil (such as 15W-xx) may be used if the ambient temperatures are warm enough to ensure that it can be pumped quickly enough to properly lubricate the engine during start-up. The importance of selecting an oil with proper start-up viscosity is paramount, and is why auto manufacturers recommend winter weights based on the ambient temperatures with charts similar to this one:


Are 0W-xx oils too thin for my engine?
As discussed previously, multi-grade oils are designed to behave like two different oil weights at two different temperatures. Since an oil is thicker with colder temperatures, a lower weight oil flows better, and better protects the engine during start-up since it is easier to pump to critical areas. So, a 0W-xx oil is a better oil for start-up, especially in cold temperatures. When the oil heats up and starts to thin out, it becomes a heavier weight oil just like a 5W-xx or 10W-xx oil would. So, a 0W-xx oil is only a “thinner” oil when it’s cold- where it is a benefit. At operating temperatures, a 0W-30 is the same weight as a 5W or 10W-30, just as a 0W-40 is the same weight as a 15W-40, etc... Therefore, 0W-xx oils tend to be better suited for year-round use in any climate, since they flow better in cold temps but become as thick as any other similar grade oil when hot.

Originally Posted by BeerViper

Yeah 10W-30 is fine in the summer ... but read that part at the end about 0W-xx oils, for the life of your engine (at startup) it's always better have a "thinner" oil to better protect the motor at startup.

Also don't ever trust an oil companies marketing, just because someone claims "10 times better protection than Mobil 1" or something like that, that doesn't mean it's better for the VQ. The oil analysis thread shows historical data for hundreds of oil analysis' done on VQ's and you can see that some oils are FAR better than others. For example, Royal Purple synthetic (expensive) has been shown to provide less wear protection than some conventional oils. The Used Oil Analysis (UOA) is your only true test of what oil will protect your engine better than another oil.

Originally Posted by g35driver76039

and it never gets cold enough here in texas to change in the winter anyway.