I would like to know what engine additive can I use
on a Volkswagen 2013 Jetta 2.0 engine?
Oil or fuel additive and for what purpose? I have never used any type of additive in any of my cars and, believe me, I have had many. Even if your VW is high on mileage and consuming oil between changes, I would just move to a higher grade oil. Manufacturers of car additives make lots of claims that, in reality, amount to nothing. A car with proper maintenance will last a long time without any additives. Example, my neighbor has a 2000 Ford Escort that just turned 200,000 miles, the car runs like day one and everything works, but it has received excellent maintenance as well as preventive mechanical service.
Additives are specifically prohibited by Castrol. A quality synthetic oil is formulated to work on it's own. Additives have been proven to harm vehicles. I should know. My Inlaws, own a huge oil company, and I'm good friends with the recently retired head of engineering, and emissions, for VW, Audi, USA. If your dealer puts an additive in your oil, no oil manufacturer will warranty your engine, because of engine failure. Total scam. Don't trust me. Call any oil producer. Dealer rip off, and against VW protocol. Spread the word.