so why do they recommend 5w20 on our cars if 5w30 would be better all around?

 

a higher weight has littel modern significance as to how well it protects. people are still thinking with a "1971" mentality about oil.

the facts are that ALL oils you will buy will be rated the same (its difficult to find oils NOT rated by the API). They pass the same tests, and will protect the same.

and the primary reason to use a 5w20? Fuel efficiency.

 

the advantage of synthetics is mostly marketing. Not all of it, but a lot of it.
first, synthetic oil is in fact mineral oil based.. its not some type of magic oil manufactured completely in a labratory.
Second, the best time to use synthetic is when your engine is subjected to ultra-high temps. It comes as a factory fill ONLY on high performance cars/trucks that are expected to reach oil temps in excess of 300+ degrees (like the EVO, corvette, etc).
During normal driving, it doesnt do anything better than normal petrolium oil. Its marketing that makes people believe it does.
It protects better in extreem heat, and flows better in extreem cold. thats about it. The "long interval oil change" is bunk, too, as the reason to change oil is from contaminates (metals, acids, etc.etc).. they are still quite present when using synthetic (oil analysis will show you this). Also, if you read the "fine print" on the bottom of any bottle of synthetic oil, it says "follow the manufacturers quidelines". I GARANTEE the oil maker will not pay for anything that fails on your engine if you change the oil only every 15000 miles.
I also GARANTEE one thing. Drive 2 identical cars, changing the normal dino oil in one every 3750, and synthetic in the other one every 15000 miles, and without a doubt the dino oil engine will be in far, far better condition.

 

You know, the advatage of full synthetic is hot climates that just never seem to end (Florida, Arizona, Cali, Texas, etc) is, as pointed out, the resistance to viscosity breakdown due to high heat. I think that is an asset in hot, traffic jammed days and driving up the mountains.

I also find the quicker flow of the synthetic in freezing temps to be an asset as you want to minimize the "dry starts" and get the oil going to the engine asap.

Correct if I am wrong, but even if I drive in heavier traffic, I should beok doing oil changes on my '07 Outiie at the 7,500 mile mark instead of every 3,250 with regular oil , right??? That way I still keep the Mitsu warranty and don't push the oil's viscosity past what Mitsu recommends.

Dude, doing 2x oil changes per year is nice, I will most likely go synthetic on my first oil change!

Ps. Why in the world would a dealership (other than in hot states likeFL or Hiawaii) change the manufacturer's recommended 5w-20 to 10w-30?? Won't that be an issue if your engine goes 'kaput' and Mitsu goes "why did you use a different oil"??

Ps#2. This is a bit off topic, but why didn't Mitsu use a timing chain on the Outie instead of a belt??! I dislike timing belts, timing chains are better, don't you think?

 

Wait something just hit me. In cold weather a 5w-20 and 5w-30 would flow the same way, however you get more viscosity protection during the FL hellish summerswith the 5w-30???

Now if you were to compare a 5w-30 regular oil against full synthetic 5w-20, which would would fare better in 90+ degree weather in traffic??

Now, I cannot see the use for 10w-30 in colder places up North, it just seems crazy to me to do that.

Oh, I am planning on getting the Penzoil Full Synthetic... anyone think that is an OK choice or is it crap oil?

Thanks for the input!

 

I decided to go with my gut and put in 5w20 mobil1 on it, its still cold here in the mornings, but it gets hot as the day progresses.

 

wow, thread number 2568 about oil... lol
short and sweet. Switchin now wont hurt your motor a bit. I just did it the other day,