quote:
Originally posted by Gene K:
Due to a decision awhile back Castrol was allowed to market Group III (Severally Hydrocracked Petroleum Oils) as Synthetic.
Over the last several years pretty much all the mainstream manufactures have swithched to a Group III Base for their Synthetic Oils. Mobil 1 being the obvious exception (Group IV/V).
A over symplification (There also certain viscosity index requirements they must meet):
Group I - Solvent Dewaxed Petroleum Base Stock
Group II - Severe Dewaxing or Hydrocracked
Group II+ - Moderate Hydrocracking
Group III - Severe Hydrocracked Petroleum or Slack Wax Feed Stock (Only recently allowed to be marketed as synthetic).
Group IV (PAO) - Isomerization of Feedstocks that are byproducts of petroleam production. (The traditional definiton of synthetic).
Group V (POE) - Esters from non-petroleum sources. such as Castor Bean Oil (Also considered synthetic).
What I/we were trying to point out was there are some cheaper oils out there that are better choices. MotorCraft is a Group II+ / III Blend that has a more sophisticated add package than either SuperTech Blend Group I / III or SuperTech "Synthetic" Group III and better base stock than the SuperTech Blend for less money. On the other hand if the "New" GF-4/SM version of Mobil DriveClean does turn out to be all low-end Group III as reported at $1.08 Qt it would likely be equivelent to the SuperTech "Synthetic" for lots less money.
For the dollar its hard to beat the Motorcraft 5w30 Synthetic Blend at the present moment. It cost $1.42 Qt at my local Walmart. It is produced by Conoco/Phillips a major producer of Group II+/III Basestocks with a new expensive form of Moly normally seen in Synthetics and some high dollar organics that can't be seen in conventional oil analysis. The Ford test WSS-M2C-929A is a double length tests that requires the oil to have twice the endurance required for API certification. I would look for a 5w30 that passes this test. MC 5w30 Blend does...
Just my opinion, that and a buck will buy you a cheap cup of coffee.
Gene