Ken how do you know what it is doing inside the system.
It may cost you big money in the future.
What do you think Toyota's or Denso's reason for not doing it is?
Why do you need fuel additive?
Don't you think Toyota dealers would jump at the chance to make some more money buy selling you a diesel service/flush yearly or diesel additive every month or so.
Any other diesel engine they will say do it but not D4D's
This is why D4D's can not run on the old high sulphate diesel and why Toyota never bought in the D4D engines before.
I'm not against fuel additives and conditioners but when you see first hand the damage they cause on CRD fuel systems you would change your mind.
I think it is a fantastic idea to use fuel additives and conditioners in old style systems.Good luck
Ask Toyota about the warranty regarding CRD systems and fuel additives.
Their is no need for fuel additives in todays engines with better fuel but if it makes you feel all fuzzy and happy keep doing it.
You might think I very stern on this subject....if I can save people a lot of money and hardship from what i say then I have done well.
Remember to keep a spare $5,000 to 10,000 free for repairs that may not be under warranty.
To many people treat CRD fuel systems like the old dinosaur systems of yesteryear.
Have a look at this link and specially "pedro" reply from Toyota.
http://www.pradopoint.com/viewtopic.php ... uel+filterGood Luck