Changing Oil

[Rock]

I just changed my oil over the weekend and went to pull the sticker off the windshield from the previous oil change.

I noticed that Castrol SY was the brand of oil used...assuming that "SY" is synthetic oil.

Rotella 1540 had been highly recommended to me and is the oil that I chose and is currently in the motor as you read.

I'm concerned about the fact that I'm going from a synthetic a non-synthetic oil. Did I just hose myself?

Please advise.

[mdrag]

Rock,

Welcome to the forums.

Your post didn't give vehicle/engine information. Since this is the Duramax 6600 forum, I will assume that your question relates to the Dmax.

Switching from synthetic oil back to non-synthetic oil will not cause a problem for the Dmax, as long as the oil meets the API rating specified by GM. Choose an oil with an API rating of CI-4. I'm not familar with either the Castrol SY or Rotella 1540, and can't verify that they are CI-4 rated.

A synthetic oil formulated for gasoline engines may not meet the requirements for diesels. For example, regular Mobil 1 synthetic would not be a recommended oil for the Dmax. Mobil Delvac 1 5W-40 meets/exceeds the API specification for the Dmax. Mobil 1 Truck & SUV Formula (http://forum.thedieselpage.com/ubb/ultimatebb.php?ubb=get_topic;f=3;t=007405#000000) is supposed to be relabeled Delvac 1, and is used by forum members. Shell Rotella T is another synthetic that meets/exceeds the API CI-4 specification.

Try a search in this forum for synthetic oil, you should find plenty of information. Good luck.

[DmaxMaverick]

You are not hurting anything by switching oil brands/types ocasionally. Most oils available use a near identical additive package. Just make sure the correct grade/rating of oil is used. 15W-40 with an API rating of CH-4 or CI-4 is recommended by the manufacturer for your engine. Extended time at/below 20 degrees F. may benefit from a 5W-30/40 oil, and is highly recommended below zero. Just make sure it is also rated CH-4 or CI-4.

Now, the arguments over dino vs. synthtetic could go on and on. My take on it is the best dino oil can't compare to a true synthetic. Most of the issues come down to economics. Keep in mind that the "cheaper" synthetics may not be synthetic in a true sense. A court order brought about by Mobil vs. Castrol allows some manufacturers to label their oil as synthetic (like Castrol and Rotella-T) because it is processed differently than traditional dino oil. True synthetics will generally be $4-$5/qt, and the "others" are less.

Hope that's not too much info....

[Rock]

MDRAG and DmaxMaverick...thanks for your timely input. Never had a diesel in my garage before and want to do everything in my power to keep her looking/running strong.

I checked the back of one of my quarts. It says Rotella T exceeds the req. of API CI-4 specification so I'm feeling much better.

This site is enough to drive a man crazy with all the information provided...I'm doing my rear diff fluid and Allison tranny filter next weekend.

Question: Can you remove the red Allison filter from it's mount without having to worry about tranny fluid running all over the place...if not, I'll seek the resources of the local dealer.

Also, in your experience with lubrication of the chasis...old grease gun didn't cut it. Had an oler Chevy that was virtually impossible to get to all the grease fittings. Do you think I'll need some flexible attachements outside the one provided at the end of the hose?

Thanks, again.

Great to be a part of such an informative sight. Thinking my relationship with this fine site is going to be rather one sided for quite some time though...all take and little give.

[mdrag]

Rock,

You will loose a few oz of tranny fluid when you change the Allison spin on - I'd estimate no more than 6 oz or so. Don't forget to remove and clean the magnet from the top of the spin on filter - then re-install the magnet on the new filter before screwing on the new filter.

Here is a link to a previous post detailing the location of the ZERKS (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=7;t=004803).

If you need to purchase the Allison spin on filter, check the ALLISON WEBSITE (http://www.allisontransmission.com/locator/index***p) for the location of an Allison Dealer, or check the Advertiser's link at the top of the page. These filters can be purchased for less than $10 each - much more $$ at the GM dealer.

[Rock]

Thanks, MDrag.

[Totljeep]

It is my understanding that if switching from non syn oil to syn oil, you much do an engine flush. Syn to non syn is a drain and fill.