I will have to ask the lab on Monday.<br>But the general defiintion of silicon is that it is dirt of one sort or another. The lower the better. It is also known that in a test run by GM many years ago , that particles between 4 &amp; 10 microns were the most responsible for wear in a engine. But I will get a answer and post it

 

[quote author=Sierra Phil link=board=20;threadid=6455;start=0#60243 date=1036119314]<br>I'm using Pennzoil 15w-40. There are lots of good brands of dino oil available. I debating whether or not to go to a synthetic at 15,000. [/quote]<br><br>Phil, I know of the oil selection available, Pennzoil is one I'd steer clear of. It is common knowledge in the engine rebuilding field Pennzoil is not a very good oil. It has a reputation of doing a very poor job of holding impurities in suspension and engines run on it for a long time get very cruddy with deposits. At least this was true in the '80s, maybe the '90s, I don't know if that's still true though.<br><br>When my current truck was new, I ran Oil Tech from Walmart, oil sample on that change came back very good, very close to the numbers I was seeing on Delo 400 (my top pick for Dino oil).<br><br>I run Delvac 1 5W40 synthetic, great all-year-round oil.<br><br>Vaughn

 

Vaughin at what mileage did you switch to Delvac 1 and what improvement in fuel mileage did you see. Also how often do you change oil??<br><br>Thanks <br>BYURAM

 

If you buy oil at Wally World for your 2003, check the container carefully. Be sure you have the CI-4 oil Two thirds of the brands were CH-4. Of the Brands that were CI-4, they had some CH-4 containers mixed in. [undecided]

 

For the record<br>If you go to the API website you will find a motor oil guide and the definition of all the categories for diesel engines.<br>It states<br>&quot;CI-4 introduced September 5, 2002. For high-speed, four-stroke engines designed to meet 2004 exhaust standards implemented in 2002. CI-4 oils are formulated to sustain engine durabilty where exhaust gas recirculation(EGR) is used and are intended for use with diesel fuels ranging in sulphur content up to 0.5% weight. Can be used in place of CD,CE, CG-4, and CH-4 oils.&quot;<br><br>I called Shell Oil in Houston 1-800-782-7852, They stated that the Rotella-T does meet this spec and since the spec was just adopted offically on September 5, 2002 that it would take awhile for the old stock bottles, jugs &amp; whatever to show the new designation. But, that the oil does now meet this designation.<br><br>Also, Remember that Cummins/DC will not be introducing the EGR engine until at least mid model year. <br><br>End of sermon

 

API website address<br><br>http://api-ec.api.org<br>