These engines don't have any fancy gizmos like variable valve timing that require a specific oil pressure derived from a specific oil weight. The spec for my 300 is 20W or 30W depending on the weather, so really you can throw in whatever oil you feel like using. For good bearing life, I wouldn't use anything thicker than 10W when cold, or thinner than 30W when hot. So, personally, I'd use 10W-30 or better.

Your biggest issues is going to be the lack of zinc in the oil.

 

I would think straight 30 would be too thick for Reno in the winter, no?

 

My truck is from 1969 when variable viscosity oils weren't really around quite yet. I do not recommend a straight up 30W for any engine. I don't even think you can find 30W engine oil anymore.

 

Well, I guess there's no standard answer here. Auto Zone had 30w on sale for $1.99 per qt (not nec. why I bought it). Just because of my slight oil leak...I thought it would be good to use something a bit thicker then 10 w 30.

I did find a recommended oil weight sheet for the 300/4.9L...I will post it when I'm not on my phone. It shows 30w for use between 32 and 90 degrees. Thanks for all the replys!!

 

"Well, I guess there's no standard answer here." Correct. There is no standard answer anywhere.

"...use something a bit thicker then 10 w 30." Straight 30 is no thicker than 10w-30.

And this is why I referred you to the two sites/forums where the 'oil wars' are permanently fought. When one wants to cuss, discuss, agree, disagree or otherwise see what everyone is using and not using in the way of oil, go to one of those sites. Even with the plethora of BS prevalent on those sites (any site discussing oil) some interesting information can be had at times.

 

I just didn't want to join another forum just to discuss oil...I know there could be several answers for me...depending on where I live...summer/winter...mileage, etc...but was just hoping to hear sure straight 30 is ok LOL

 

Straight 30 is just fine especially for summer use...the straight weight oils were all that were available for years and many an engine went many miles on them. A multi-weight might be better in the winter time especially for cold starts and short trips. it all comes down to your preference, your choice.

 

Well, now with winter coming up...maybe I shouldn't use it now (it doesn't get much colder then about 30 here though). I was hoping to find something for all year use and a bit thicker/heavier then 10w30 due to my slight oil leak...so I don't loose quite so much oil in-between oil changes.

 

Winter in Nevada sounds like a summer in Canada...

Once your engine is warmed up, the 30 wieght oil should be in it's operating range. using too thin an oil might cause problems once it's warmed up.

I tl;dr this so going back to read about the zinc as I just stuffed a new rebuilt engine in mine and don't wanna mess it up like I did with the old ones

Edit: Okay, going to look for some synthetic diesel oil. I really like synthetics as it gets kinda cold where I am (-40 don't matter if F or C)

 

You know he means 30 Fahrenheit, right?

 

Oh, thought he was about using 30 weight oil

 

Yeah, winters in Nevada are fairly mild. I'm from Michigan, so I know how winters can be. Yeah, the zinc thing is a whole different thing...just one more thing to figure in I guess :/

 

Even diesel oil since about a year ago has highly reduced amounts of zinc. Just go buy whatever oil and then add ZDDP.

 

Whats the recommend weight, brand w/ the right amount of zinc in it??

 

At least 10W-30 oil and then ZDDP additive.