Wouldn't it be better to switch to a synthetic blend for high mileage vehicles?..Not sure what the PO has in mine but that's what I will putting in it when the fluids get changed this weekend. Any brand Dodge likes best?.
I run full Amsoil and fully endorse it. I'm able to go 10,000kms between changes now running 5W20 in my HEMI. For your 5.2/5.9L tom's got the right advice.