So I read a plethora of threads regarding 5w30 vs 10w30. It seems like the first gen G's could use a couple different oils i.e. 5w30, 10w30, 10w40 but our second gens should only use 5w30 (and the owner's manuals concur).

So I ask because on saturday I changed my oil and realized afterwards I used 10w30

I've driven probably 15 miles on it....the motor seems to rev a little smoother but it seems to idle a little louder (both can be a placebo, idk).

Should I change right away back to 5w30? Not looking forward to changing my oil again but the last thing I want is unneccessary wear or damage. Any assuring thoughts in either direction would be much appreciated.

 

You should be fine. Just go back to 5W30 on your next change.

 

10W30 is "thicker" in viscosity than 5W30. So you will see a decrease in gas mileage. In my opinion, you don't have to use 10W30 unless you are running on a FI setup or in a 100F degree zone.

 

how do you realize the wrong oil after you've pored 5Qts in? Don't think it'll harm anything but like suggested, just go back to correct viscosity for your temp on the next oil change. The book does recommend 10W 30 for a certain temp, just check if you fall within that criteria.

 

It's regularly 105+ degrees here, should I switch to 10w30?

 

Man that's a good question - it just occurred to me after I finished changing the oil to verify I got the right kind and lo and behold the empty container says 10w30. Doh. I'm prone to do dumn stuff. Not so much so that I'd let anyone else touch my car unncesessarily though!

I read the owners manual carefully and it said 5w30, any other types could result in engine damage. Maybe I missed something. I read an article that said with all the complex small parts related to valves/lifters/tming etc that 10w30 could cause damage since it doesnt flow into all the small nooks and crannys as easily as 5w30 (I realize they both act as 30 but right a startup, etc).

I guess I'm just still on the fence between changing back now or waiting til next oil change.

 

Just change it back! Just in case who knows......

 

When I was in California, I used 10W30. Then I moved to Minnesota and started using 5W30. Some information about oil so you can make a decision:
- Higher viscosity oil: higher protection, more stress on oil pump (harder to pump thicker oil), slightly reduce gas mileage.
- Temperature affect: higher temperature causes oil to flow better (wider space between molecules => thinner the oil) but also decrease the protective aspect of the oil.

 

I can't verify, maybe I confusing my M/C owners manual with my car's. I was certain i saw that chart in my G35 manual that shows temp, and the arrows showing you which of the 2 oils (5/30 10/30) to use. Maybe I'm all confused.

 

oil change is one of the easiest things to do on a car! just change it and relieve ur worries!

 

oil is all the same when warmed up. Its cold that 5w or 10w plays a difference.

I wouldn't worry about it too much. I did the same mistake but i have a first gen. I bought 2 10w30 for the parents and 1 5w30 for myself. I didn't think and grabbed one. No issues, no MPG lost.

 

It won't hurt. Go back to the recommended weight next change and call it good. Chances are (looking at the national map) that's it's still hot as the dickens where you are, so by 2500-3000 miles the temps will moderate and you'll be good to go.

If you can actually measure a significant difference in your mileage I'll be greatly, and I mean GREATLY, surprised.

 

5/30 is the best I swear by mobil 1