Straight out of the 2005 FSM:
An SAE viscosity grade is used to specify the viscosity
of engine oil. Use only engine oils with multiple viscosities
such as 5W-30 or 10W-30. These are specified
with a dual SAE viscosity grade which indicates the
cold-to-hot temperature viscosity range. Select an
engine oil that is best suited to your particular temperature
range and variation. For 3.7L/4.7L engines SAE
5W-30 engine oil is recommended for all operating
temperatures. For 5.7L engines SAE 5W-20 engine
oil is recommended for all operating temperatures-
.These engine oils improve low temperature starting
and vehicle fuel economy. Refer to your engine
oil filler cap for the recommended engine oil viscosity
for your vehicle.

 

and hence MY reason for this post! My owners manual AND cap say 10w-30, I've always used 10w-30 either Mobil 1 or RP. I take advantage of a dealer coupon because of the free rotation I was due for and they stick in 5w-20 (not even one grade thinner 5w-30) and tell me Chrysler "changed" the specs.

I still ain't crazy about it...

 

If Chrysler released something to that effect, they should be able to produce the bulletin stating so.

 

yeah, I was not gonna be a ***** and go back and question it further, but then again, hey if the shoe fits...

 

I had mine changed at my dealer today. 7qts of oil and Mopar filter with coupon cost a total of $19.40

I asked them and he said the same thing, they have even switched their bulk oil tank from 10w30 to 5w20. It's all they use now in all late model Mopars per Chrysler.

 

My 4.7 HO oil cap says 5w-20. I can't imagine there would be any adverse effects to using it, especially if it's full syn. Unless your engine already has a sludge issue, and the thinner oil breaks it up and carries to, and clogs up oil passages. You may also want to keep an eye on the oil level, as the thinner oil can get by the rings a little easier....but this is usually very minimal. Also, if you have a seal leak, it will intensify that problem.

I really wouldn't worry about any blow by. The benzes and bimmers that use 0w eat a rediculous amout of oil. Just keep an eye on that level until you know what to expect from it.