I read it was a mileage thing aswell. It looks good if you can advertise a certain mpg figure but you have to use 5w/20 oil. At the same time the 5w/20 will cause more engine wear. I found that useing 5w/30 and 5w/40 wasen't a problem other than fuel mileage.
I have non mds hemi.

 

Thanks for all the replies. The last few make a lot of sense. I think I'll go a little thicker in the summer and thinner in the winter. Hemi's tend to drink gas like alcoholics so every little advantage helps.

 

Lighter oil is better, allway will be. I'm of the old school days, 10 w 30. 10 w 40, I had a old ford 400 ( LTD ) valve seals will toast, but when I ran the heavy est oil I could find, engine did not burn oil as bad as 10 w 30.

Times have changed, as well my thinking, a light oil pumps quicker, rolls of the cam lobes quicker, circulates threw the engine quicker, a heavy oil is harder to pump and will not pick up as much contamiantes as lighter oil.

Winter, or summer, lighter oil is better.

 

One thing I'm not sure anyone mentioned is that the lighter oil will provide more engine protection at start-up, where most of your engine wear happens. I planned on switching the truck over to Amsoil 5w30 synthetic which is comparable to a conventional 5w20 in thickness anyways. But, it sounds like most of you guys are running 5w20. You 5w20 guys using conventional or synthetic?

 

u could always go with those tiny crappy hondas where they are running 0/20....aka water pretty much...there is not much to that oil. That would be the last vehicle I would drive.

 

So does Mercedes in Europe.

I'm not disputing you man, just saying I know an 04 that has 5w-20 on the oil cap, I saw it myself.But either way I don't think either oil would hurt anything.

That could have been replaced in the last 5 years.

 

i can near garauntee that your engine could care less if you gave it 20 or 30. most of the guys on here that have opinions have just that, opinions. and i bet if you were to ask an engineer at chrysler it would be a guessing game. just use what you can find. i.e. amsoil doesn't make a 5w20, so use their 30 if you want to run amsoil.

btw, amsoil 5w30 is not like other 5w20s, its like other 5w30s...that's why its called a 5w30.

 

amsoil makes a 0-20, 5-20, 0-30 and 5-30. The 5-20 is the XL oil, good for 6 months or 7500 miles. all 4 are full synthetic.

 

Thats exactly right, thats why we have the OIL Thread in the FAQ section so we don't have ridiculous threads like this.
Believe it or not I realize this but all I was doing was stating that I had seen a 04 with 5w-20 on the oil cap. I really could care less if there was 20w-50 it. It ain't mine so really I don't care. I run what I run because it is my opinion that its what I should run in my engine. I wasn't trying to sway the OP to run any special grade of oil or trying to imply that he was wrong about what he had read in his owners manual.

 

It seems like people are getting a little testy now. Sorry for bothering anyone. Ya know, you don't have to post a reply if you don't want to. I think I'll unsubscribe to this thread now.