Re: tcw 3 to diesel
Use the makers (OEM) fuel additive.
IMHO, Motorcraft has the best product, on the market, to fight poor fuel quality (an industry problem). It is known as ""best in class".
If the people that are PAYING YOUR WARRANTY BILL find TCW-3 in your tank (or any other crap), that COST will go DIRECTLY to you-JUSTIFIED.
AVOID alcohol based additives at ALL COST. Read the label.
You want to get your cetane rating to 45+.
The Motorcraft product will do that and NOT affect any warranty issues. However-again-I recommend your vehicles OEM product for cetane boost and anti gel.