View Full Version : NO oil war just info on dexos,please

10-10-12, 12:30 PM
hello everyone, i've been reading about GM's and dexos1,does anyone know if its good/bad/indifferent for a N* ?
just trying to increase my knowledge.... thanks Ed....if there is an old thread, please direct me

10-10-12, 01:29 PM
DEXOS is a GM oil/additive formulation spec that conforms to GM's latest thinking on engine lubrication coupled with compliance with the latest reduced numbers for EPA oil additive regulations. It carries a SN API rating and could be used in any 2010 (??) or later engine.

Your engine was built during the time of API SJ oil service designation, so you would be wise to do some homework and try to conform to that additive package in order to protect your flat-tappet cam setup to the max.


Manic Mechanic
10-13-12, 11:53 PM
Any engine I own that uses flat tappet lifters in the valve train like the early Northstar has gets oil that still has some Zinc in it. It protects the metal to metal wear points from galling. Any of the current oil that has the star seal that says "for gasoline engines" is very low zinc. The oils that still have a lot of zinc are labeled as "racing" or for Diesel engines or off road use like John Deere oil etc. I've had to replace a few LS V8 cams and lifters already due to the crappy oil in widespread use nowadays. Zinc when burned off in consumed oil can eventually coat catalytic convertors reducing their efficiency or killing them. But I would much rather replace a convertor every 10 years than an engine anytime.


10-14-12, 05:44 PM
Read up on API oil specifications and learn why the below quips..............

The EPA loves you ....the EPA says nothing ... the EPA hates your guts

11-07-12, 01:19 PM
hello, are you saying I should use diesel oil because of the higher zinc content?

11-07-12, 03:57 PM
No, I am not saying "use diesel oil" - I am saying "Check out the HD or Long Life conventional multigrade (10W-30) oils because they are formulated with the anti-wear/anti-scuff additive package that was recommended for your 1999 engine." Your API spec was SJ. Google it.

The old wives' tale that HD oils are exclusively "diesel oils" is patently false. For grins and kicks, get into the SOPUS (Shell Oil Products U.S.)(Pennzoil, Shell, Quaker State) and get to products, heavy duty, truck, and find the spec sheet for Pennzoil LongLife oils - 10W-30. We run tons of the stuff in a 15W-40 grade in all our GM 454 and Olds 455 marine gasoline engines. No tappet or cam wear - none, and the additive package will NOT affect catalytic converters from the mid 1990's through 2004.

If you want the cat's meow, contact Brad (C66Racing), our resident AMSOIL vendor - he can recommend oils for you or get into www.joegibbsdriven.com (http://www.joegibbsdriven.com) and look at their various oil formulations - products, street engines.

Your engine, and to some extent, mine - were not designed for the oils mandated by the EPA for today's emissions specifications. Your API spec was SJ, mine was SL - and neither has the reduced additive packages of today's SM and SN oils. I can get away with SN oils because of the roller cam followers - you have flat tappet followers and they need all the anti-scuff protection they can get.

11-07-12, 04:36 PM
Good info from both manic and sub.

Here is a flat tappet cam from a 82 vette that ran Mobile1:

We usually upgrade to a roller on classics going to be driven, but this one they want as original as possible so Brad Penn going intop it.

I also agree that a good Amsoil rep can match the best oil for your engine.