Super Tech or any other oil MUST pass the same API tests to be certified in a category such as the ST diesel oil.
If the ST oil has the API certification,it meets the engine manufacturers qualifications.
Spending more on a product doesnt mean that you are getting a better product but may only be the cost of advertising and the name on the bottle.
ST has been reported to be made by Shell,XOM and Warren Performance Products.
As far as the rumor that ST is used oil,that just doesnt sound right.
Here is the website of WPP:
www.warrendistribution.com
If it was,it still has to be refined just as crude oil does before it can be bottled and used.
It still has to meet the same API specifications that any other oil does.
All oils that have the API certification must pass the API standards,cheap or expensive.
It isnt just a bottle of used oil that has been filtered.
The American Petroleum Institute(API)would not allow such to go on.
The company that made such oil would face
several court proceedings for damaged engines.
Super Tech has shown over and over to be a good oil by people that are members of this board yet some keep saying that it is a bad oil.
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=22;t=000457#000000]
This Ford engine did fine on the ST oil.
7.3 liter