I have a 91 D250 cummins with 118000 original miles. It is in unbelieveable condition. All maintenance has been done at a Dodge dealer according to the owners manual. I asked them about changing to synthetic oil and they said no. Should I start using it? and if so, what brand. I would appreciate all comments.

Thanks, Bob

 

can you use synthetics...yes you can. the best IMHO Amsoil, or Royal Purple. I'm running AMSoil in mine and am realy likeing it.

if you plan on doing the change yourself you will need to get atleast 6 gallons. dump the old oil, put in the synthetics. change the oil around 3K and you'l be good to go. I say thissince theengine has some miles on it there will be a good bit of sludge the synth. will pick up. changeing it will remove this. add in a bypass filter and you can go nearly 25K between oil changes.

 

Hey Drew I saw Steve's thread about installing an oil bypass system and if you don't mind think you could explain to me what exaclty the oil bypass does. See i'm looking at purchasing a CTD very shortly and i'm trying to learn as much as possible so i can care for my truck so that it will last me as long as possible.

 

all it does is filter a small amount of oil, under low pressure through a media that is packed MUCH tighter than a normal oil filter. the oil that comes out of this filter is VERY clean compared to the stock filters capabilities.