Did any of you who have changed to the synthetic oil first drain your old dino oil, replace it with new dino oil, then run until hot, and then change to the synthetic along with a filter.

A friend of mine did this with his Dodge 5.9. He said he did not want to put in new synthetic with oil having 5K miles on it. He felt the diluted dirty oil would be bad with his new synthetic.

I'm ready to change with 29K miles and have purchased the Rotella synthetic and filter.....Thanks

 

Everytime you change the oil a little bit of the 5k used oil remains. Whats the difference if the new oil is synth? Just a waste of money.


Bill

 

You will never get it 100% pure. Don't worry about it. The 6.0 retains approximately one quart of the old oil everytime you drain it. No biggy!