Should synthetic oil be used in a diesel engine?

Is synthetic oil beneficial in a diesel Cummins engine, or is regular 15W40 weight oil OK?Should synthetic oil be used in a diesel engine?
Just make sure its rated properly. If its a 6.7 you need the CJ rating. With the 5.9 the CI+4 rating is great due to higher TBN but CJ rated will do just as good.





Just make sure the engine is good and broken in first. If you've towed a decent load a few times I'd say you're good to go. If you haven't ever pulled a thing it might not get broken in until 15000 miles or more.





Personally I run Shell Rotella 15W40 and the last changes have been CJ rated. I do oil analysis and everything has always came back great. I changed my oil right at 6000 miles last time and the report came back that my TBN had only dropped about 1/3rd of the TBN of unused oil. Basically this amounts to the oil still having a lot of life left in it and the additive package is still in good shape. They actually recommended that I could double my mileage before the next change.





A 5W40 synthetic like Shell's Rotella would really help during a cold winter start. I have a block heater on mine and it helps get the 15W40 heated up and the pressure comes up a lot quicker.





If you have a Dodge I highly recommend the block heater. Actually the truck already comes with the block heater, you just have to install the cord. You can order the cord from Mopar or buy a $15 universal one from Napa.





To install the cord, take the intake tract off between the airbox and turbo. The block heater is directly rear of the oil filter. It will have a black screw on cap on the terminals. You may have to use some channel locks to get the first turn off the cap but it will back off easily.





Screw the cord end into the termination and drop the cord down to the frame and run it to the front bumper.





Of all the things I've ever done to my truck, getting the block heater going was the absolute easiest thing I've ever done. It was also one of the cheapest and best things too.





Getting cab heat almost instantly is awesome on a cold day!!!





Should synthetic oil be used in a diesel engine?
Go to cummins.com and check out information on engines.....there is also a really good PDF on there about MPG....


They will illustrate that synthetics are nothing much more than expensive in the long run......


I would use a good oil like Rotella T, or Mobil Delvac otherwise.





I have a 2005 VW diesel I bought new....and have always used Mobil 1 or the Castrol equivalent synthetic....I love the stuff....and I also use Power Service year round in my fuel....Winter stuff in winter...Summer stuff in warm weather....No biodiesel either......you could get a bad case of algae in your fuel system in cold weather with this schitt....


Then big $$$ to repair.......


BTW, My employer just got me a 2009 Freightliner with a Cummins diesel....love it.....
I have an 04.5 and contacted DC and they said you can use SYN if you like but don't go over 10,000 mile per oil changes or your warranty is void%26gt; My friend has the same truck and uses SYN and I see no difference%26gt; except he pays $150. and I pay $60. your call%26gt; I use Rotella T
Personally, I prefer the regular oil changes that I do with regular oil. But as long as the oil is rated for diesel applications it should be OK
yeah