5w30 versus 10w30

[sawdust123]

OK, the manual calls for 5w30. But heck, I live in coastal Southern CA. I never see temps below 45 or over 100. It doesn't seem like 5w vs 10w is going to make much difference to me. Or, maybe I'm just trying to rationalize this because the garage I like to go to doesn't normally have 5w30 in stock. What say all of you?

[SuGamer]

I'd still go with 5w30, it's not as thick. My last oil change was at the dealership since they offered me every other oil change free, so I let them do it. Big mistake. They put in 10w30. I just changed my oil now and put in 5w30 Mobil 1, and you can immediately feel the difference. It idles so smooth, you'd think it was off.

[Mean Green]

My dealer uses 5W50 Castrol Syntec in my GT.

[quicksilverdon]

quote:Originally posted by SuGamer

I'd still go with 5w30, it's not as thick. My last oil change was at the dealership since they offered me every other oil change free, so I let them do it. Big mistake. They put in 10w30. I just changed my oil now and put in 5w30 Mobil 1, and you can immediately feel the difference. It idles so smooth, you'd think it was off.

Find it hard to believe it was due to the 5W difference unless you're in Cold country - suspect more of it was due to synthetic oil.
I think 10W 30 is fine for a car that won't see freezing temps.

[SuGamer]

quote:Originally posted by quicksilverdon

Find it hard to believe it was due to the 5W difference unless you're in Cold country - suspect more of it was due to synthetic oil.
I think 10W 30 is fine for a car that won't see freezing temps.

You're right Don, but you can testify how cold it's been in the tri-state area lately! [:0]

Tom, you're lucky you actually have a dealership service department that knows what they are doing!

[Gary04GT]

If you have a turbo engine then, IMHO, there is only one way to go: 5W-30 synthetic oil. I use Mobil 1--it works for me.

[SuGamer]

quote:Originally posted by Gary04GT

If you have a turbo engine then, IMHO, there is only one way to go: 5W-30 synthetic oil. I use Mobil 1--it works for me.

Once again Gary, you hit it on the nose!

[2step]

The first number has to do with the viscosity, the ability to flow when at a cold temperature. The second number has to do with the amount of protection when hot, the thickness of the oil film.
There is a common belief that the lower the "w" number, the better the gas milage. I'm not sure if that's always the case. I'm personally a believer that a synthetic will give better MPG than a non of the same weight. Especially if you factor in the fact that all oil will thicken with use but synthetic will thicken more slowly.

Here are a few of my opinions that are of course open to correction:
-Synthetic longer lasting than non.
-Synthetic less friction than non.
-A 10w in the warmer south will flow as well or better on cold start as a 5w will in the cold north.
-A 5w will drain off the engine parts more after shut down than a 10w, leaving less oil protection at start up. (I'm less sure about this one so flame away.)
-The difference in using a 5w up north vs. a 10w down south is minnor and will not be any harm.

[B)] or [|)]

[PT4U2C]

Great debate here, gang! Each of you make strong cases and each of you are right! It's all about what you believe, your experience, your perceptions. And there all yours. I agree with each of you and I feel in the final analysis, each of you will have super results. A more critical issue is keeping the oil as clean and as fresh as possible--more changes, better filters, warm -ups, cool downs(turbos). My peceptions, like yours. LESS FRICTION is the ultimate goal, along with coating of moving parts..less friction.

PT4U2C

[SuGamer]

quote:Originally posted by PT4U2C

Great debate here, gang! Each of you make strong cases and each of you are right! It's all about what you believe, your experience, your perceptions. And there all yours. I agree with each of you and I feel in the final analysis, each of you will have super results. A more critical issue is keeping the oil as clean and as fresh as possible--more changes, better filters, warm -ups, cool downs(turbos). My peceptions, like yours. LESS FRICTION is the ultimate goal, along with coating of moving parts..less friction.

PT4U2C

I couldn't have said it better myself! For me its Mobil 1 5w30 and a K&N filter every oil change. Makes my PT happy!