I've searched but I just don't see where anyone has actually answered this question before. Is there any real reason that I shouldn't use 5W30 synthetic in my 2008 Ram 4.7? I know the owners manual and the oil cap both say 5W20, but will 5W30 cause a problem? This isn't a Hemi, so there isn't any MDS to worry about.

5W30 has been easier to find than 5W20. That may change, but for now it's true. And it allows me to keep the same oil for both my trucks. They use the same oil filter, so using the same oil would be nice, too.

 

And take a look at the green underlined text, like 2008 Ram and oil filter. If you point at the Ram text, you get an ad for Chevy Silverados! I thought this was a Dodge forum!

 

In the 4.7 I don't think it's that big a deal, although modern engines are a lot pickier with their tolerances in oil grades than they used to be.
Back in the day, when most called for 10w-40, I'd put 20w-50 in anything I had after the odometer hit 50k, or if there was a hint of a slight oil loss problem (burning or leak).
If the owners manual doesn't specifically say "use this grade or else" kinda like the MDS Hemi's say, I think you've got a little play of at least one grade plus or minus.
I run 5w-20 in my '04, even though the manual calls for 5w-30, because the '05s call for 5w-20 and there is no difference between an '04 & '05 and I run a cooler thermostat, so my engine doesn't get as hot as stock, thereby, allowing for a slightly thinner oil. Since my '02 4.7 H.O. in the Grand Cherokee calls for 10w-30 and I don't want to run that in the truck, it's no case quantity purchases of RP for me anyway...

 

i know there were some old yota engines that required 10-30, and were later approved for 5-30 or 5-20 by toyota, many years after they were created. you might just be ahead of the curve if you use it.

not saying this will happen, but automakers don't always consider all the options, benefits, and consequences.

 

since the differences are so small
in terms of MPG
or max power at wide open throttle
why not stay with the recommend viscosity
at least until the warranty expires?

 

If you can wait for an answer until Thursday night, I play golf in a 9 hole league with the GM of a local Dodge dealership and his service mgr. I'll post the question to him. (don't worry, they are used to it, they ask me to help them with their game and I ask just as many truck questions...)

 

No problem there. It'll be awhile before I change it again.

 

Well, I'm playing golf with them if the tropical storm moves completely thru. Now they are talking like it's gonna emerge over the atlantic off the florida coast and maybe stall...

 

I haven't had any problem finding 5W-20. Walmart carries it in Mobil 1 and many other brands.

 

Walmart has anything!!


My g/f's 99 mustang calls for 5w30 or 5w20, i dont remember which one. But anyway, it loses about a quart or oil between oil changes, seems to be burning it off cause it doesnt leak. So i grabbed some 20w50 that i use in my 70 Nova and poured that in her stang. The car knocked like crazy till it was warmed up. I drained it, and added 5w30 and its stopped knocking. I was actually surprised cause the car has 170k on the clock. Its still somewhat tight for a high mileage car. I have to give ford credit for that one, they must be doing something right to keep tight clearences...

I would try to run the 5w30 and see what it does, if you hear anything. Just drain it and add the correct stuff.