I was kind of out of it on Sunday when I was buying oil and picked up the case of 10W40 instead of 30. Im not really worried, I will just change it sooner than usual.

I know I've seen some guys running 5W30, mostly 10W30.

Who is running what? Just curious. Thanks.

Also, I seem to be putting in about 4.5 qts. Does that sound normal?

Your engine will suffer no harm from running 10W40. Maybe you can sell/swap the rest of the case to a buddy who drives a different make of car.

I use 5W30 "ordinary" (non-synthetic) oil. I don't have any particular brand preference. I usually use Texaco Havoline because it is often on sale in local stores.

The Owner's Manual says the capacity with a new filter is 4.25 quarts. I think you can trust your dipstick.

To properly "index" your dipstick(LOL) you should do the following.

1) Determine exactly how much oil you car needs. ie.. look in owner's manual etc.. Let's say is 4.25 qts like Mr. Martin says.
2) Pour in exactly that amount into the crankcase.
3) I would wait for xxx amount of time to make sure it's all drained into the pan. ie.. 1 hour.
3)After making sure your car is on level ground, take a dipstick reading. Note where the oil level is shown. Make your own mark if you have to. This is what exactly 4.25 qts of oil looks like. Most dipsticks are fairly accurate but this is one way to make sure it is.

I run 5W30 Mobil 1 Synthetic. I usually use about 4.25 quarts as well :)
-hype

Oil Type
 

As long as the oil brand has the little circle with the type "API SERVICE SH or SJ" then the oil is just fine. If it says it "energy conserving" then that,s even better. I only pay around 80 cents a quart for mine and believe me it,s just as good as the synthetic stuff that people are using just as long as you are changing it around 5,000 miles or so.

I follow Nissan's recommendations, "5W - 30 or 10W - 30 are acceptable, 5W - 30 is perferred," and I use the 5W - 30. I just changed the oil& filter and got 4 quarts 20 ounces in it. Right up to the full hash on the stick. (The car IS on level ground), so that's close to 5 qts. BUT, after I drained the oil, I jacked up the left side of the car and an additional half quart or so drained out. The drain plug hole is a quarter inch or so above the bottom of the pan to make room for the thread area of the plug hole.

you can also use mobil 1 0w-30 , thats oil is very weird. ITs from like -42 to something very high :D its temps are lower and higer then anything else i have seen.