anyone...whats the minimum amount of mileage recommended prior to switching over to synthetic oils? thanks in advance, bobhttp://dieselplace.com/forum/smileys/Approve.gif

Bob,


No Minimum .. you can start using a synthetic HDEO at day one as long as the oil meets the specs for the Duramax... API certified 15W40 or 5W40 with CH-4 or CI-4 rating.


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I'm waiting until 10-12k before I make the switch.


Some people change sooner, some later. The Dmax seems to be all seated around 25k. I just picked 10-12k as a happy medium.


Vettes come with synth right off the line. Some OTR guys swear it's demon juice not fit for diesels.


We have big GM EMD emergency gen sets at work that run on Delvac 1300 or Delo 400.


We do oil analysis and can not justify the cost to run synth. (500 gal sumps).

I waited until 20k to switch my DMAX over. I guess I just wanted to do a few "flushes" with dino to make sure all the crap was out of the engine before doing 10k drains with synthetic.

Mobil used to recommend 6K before using Mobil 1. I haven't seen that advertised for a long time now.


Dave, we used IR synthetic with extended change intervals in our Centacs. We did oil analysis on a bi-annual PM. We had over two years on one running 24/7/365 when I retired. They always looked like new inside when we took them down for a rebuild. Later! Frank

Many new cars come with syn in the engine.

I would wait at least 5-10k with a diesel. I waited till 9200.

thanks guys..for all the valuable input and how you personally maintain your rigs...currently i am at 10500 miles..mostly towing my 9k fiver...its feeling better all the time...i justed changed my oil recently..using pennzoil 15 -40...will consider going to a synthetic in the future because of our cold temps in winter and i know it will flow faster...bchttp://dieselplace.com/forum/smileys/Geek.gif