I'm the last guy in the world that would fall for gimmicks, after all, I've worked as a development engineer in automotive powertrain (GM premium V8s and diesel group) up till I retired out several years ago. I still work in automotive but now with a supplier in body electronics. While I'm thinking of it, all those who create and propagate those automotive conspiracies, keep them coming cause we always need material to laugh about at the water cooler.
I never paid much attention to Seafoam until recently, in fact last summer. I read here what you folks thought of it and I was tired of spending so much time trying to start my two cycle engines, I gave Seafoam a try. Guess what, it worked, even after extended off times, the weed whacker, chain saws, they all start after two or three pulls. I add two ounces of Seafoam to my one gallon gas/oil mix.
My Tahoe (2003) developed a lifter tick at 130K miles when first started, after two oil changes using a high detergent oil, the tick remained. On the next oil change I added 9 ounces of Seafoam to the oil and after 5K miles, the tick went away. I am now at 185K miles and still no tick.
Now I am a fan of Seafoam, I don't care what ingredients in Seafoam make it do what it does, I am going to continue to buy and use Seafoam.
As far a diesel fuel treatments here is what I've learned by asking. My tractor dealer (a Kubota dealer since the early 70's) said not to add any treatments, it is not needed. The fuel terminals add what is needed for our area. I have three diesel utilities I use on my property and all of them run just fine. The
B3030 and the RTV900 are used thought the winter and start and run just fine. All three are Tier 4 diesels.
I called a friend I worked with at powertrain and asked him about additives for the latest versions of GM's diesels. He consulted with one of the staff chemists and told me the same thing my tractor dealer told me.
There you have it, like it or not, my experiences and qualified opinions.