5W40 or 15W40 in 6.7 CTD?
So the owner's manual in my 2015 Ram says to use 15W40 oil in the 6.7 Cummins diesel, unless the temp is going to routinely be below 0*, in which case you should use 5W40. Here on Long Island, the ...
Forum Discussion
BurbMan wrote:
This is what the owner's manual says:
I went down the same path wondering which to run when I first got my Ram. The easy answer is run synthetic 5W40 since the arrows point to infinity in each direction. When I first got my truck I went to my local dealer for some Jeep parts and while there asked them which oil they use for servicing Cummins engines. The guy turned around and pointed at stacks of Rotella T6 5W40 on the shelf and told me that's what they put in every single 6.7L truck. I know, DEALER can be a 4-letter word, but if they are using this oil for trucks under warranty then I'll go with it.
Another point for me is oil change frequency. The manual says to change oil every 15,000 miles or 500 hours and I don't even come close to that mileage in a year. So, I just change my oil once a year and with the 5W40 I'm covered for any temperature range and I don't have to worry about it.
KJ
