I always use Shell Diesel fuel in my 6.0 and I have tried a fuel additive a few times and noticed that my truck doesn’t run as well.
I don’t want to say the name of the additive in case it works wonders for others and I wouldn’t want to discredit the company but it is one of the Friction Modifier Type additives.
It could just be my imagination but when I use it as directed I notice my truck just doesn’t seem to run right and has power issues, sounds like an exhaust leak and much louder sounds under the hood from when I use nothing at all.
Any comments, advice, joke and insults are all welcome.

 

The only fuel additive I use is the Motorcraft Cetane Booster. I don’t notice a difference in terms of noise/performance, but I consistently get at least .5mpg better fuel economy with it.

I tried the Archoil Fuel system cleaner, I think it’s AR6400 or something. Supposed to use it every 5k miles. Didn’t notice anything during the first 5k miles, will try it again since I bought a few bottles of it 🤷‍♂️

 

Since I sell Amsoil I use the cetante booster and cleaner started getting about 1mpg better while towing. It could very well have been a dirty system and any fuel additive could have done the job of getting that 1mpg but we'll never know. Since I'm constantly hauling different trailers all the time now it's hard to do an A-B-A comparison anymore vs when I towed my own trailer on specific routes for thousands of miles.

 

Perhaps you used one of the two I'm going to mention but I respect that you don't want to mention names.

I only have about 11k use of using Hotshot's Secret Everyday diesel treatment. I have used their Diesel Extreme fuel treatment a few times as well. I purchased the truck with about 309k on it and decided to use the additive from the first day I got it. I also used their Stiction Eliminator formula as well as their Friction Eliminator for the next few oil changes.

Recently, about 1,000 miles ago, I changed oil to Ford Motorcraft 15W-40 (recently was using Super Tech 15W-40) and decided to try the Rev X oil treatment along with their Distance + Gold diesel fuel additive. It's about double the price for both (roughly) but I believe the fuel treatment is "supposed" to be double the fuel cetane so if this is true, then I guess it sort of works out. Is it double? I don't know. I don't have the know how or the equipment to test it like pretty much every consumer. Unfortunately for me, I have a few issues I'm dealing with since I got the truck that are coolant and oil or engine related (coolant puking out of degas at 17 or 18 pounds of boost or more and oil consumption issues). If you care to read about those issues, you can search my name I guess.

I monitor my fuel mileage very well and do my best to fill my tank up until it actually levels off and not just stop at the first or second "click" of the fill handle. Typically, I like to compare when I'm pulling trailers but since switching to the Rev X oil and fuel treatment, I haven't really been pulling anything too heavy or for long enough distances to really notice or compare fairly. When I'm driving out of town without a trailer, I unfortunately don't like to "take it slow" so I'm doing 85 to 90 mph and sometimes 95 mph so it's really not fair to do a mph comparison at those speeds. Plus, it's not a constant speed so it would be difficult to measure. At least with pulling trailers and going slower, I have a better way to compare since the situations are similar and speeds are lower and fairly consistent. For in town measurements, that's really hard I think. Since it was colder over the last few months, obviously your fuel consumption is going to go up if you're letting your diesel warm up (like you should) and/or idle more than if it was warmer like it is now. So, I don't know if you can do in town comparisons since so many variables change.

I don't know if the mileage has improved but I am seeing a difference in the oil consumption but that's a different discussion.

I don't know what to think about additive discussions or whether they are really "necessary". All I read about is how bad the diesel fuel quality is to the point that I'm scared of not using something. But, aren't the diesel fuel manufacturers "supposed" to be putting some sort of "additives" in their fuels as well? So, why are we needing to put additional additives in?

My wonder is: If I don't put the additives in, am I doing so much damage or increased wear to the parts/components that it's going to reduce the life of the engine by 100k miles or 30k, or 5k? If it's 100k or at least 30k, then okay. But if it's going from an additional 100k down to only 95k because I didn't put additives in, then I don't see how it's worth it to spend all the additional money on the additives.

As far as the performance goes, I don't know that it's any different.

I would love to see a head to head comparison with a few different additives and see if there is even a slight improvement of say 1/2 mpg over another. The problem is, do you have to drive only one full tank to "flush out" the old additive and let the new additive work its "magic" or do you need even more than that and say it's 3 or 4 tank fulls? Also, it's virtually impossible to get the same conditions to know if it's different. You almost have to do a 200 mile trip one way and 200 miles back with one additive and then do the same trip with the other additive going the exact same speeds with the same type of wind (within 5 or maybe 10 mph max) and wind direction and temperature to do a fair comparison.

If you do the same trip back to back in a day, even then it's going to be difficult to have the same conditions. Either the wind will pick up one direction or the temperature will change by 30 degrees or more which will change things. I don't know. I have a good 200 mile trip I can take to compare so maybe I will one of these days.

 

Thanks Eldridge, very informative.
I will be reading your other posts concerning your other issues.
I fully agree that the Fuel manufactures are supposed to be adding something to the fuel but to get that information may be difficult and how do we know if its really in there.
It seems like another mystery with these engines as to weather to put something in the fuel or not.
For me the fuel scenario falls under a damned if you do and damned if you don't , complimented by I just don't know.
I do like the idea you suggest of making a 200 mile trip with one product and then trying another.
It would be nice if Ford or International chimed in on this forum but I doubt that will ever happen.
Thanks again for these great observations and ideas.

 

I wish I was more educated on these things but I'm just not. And even though I'm trying to follow things as best as I can in some other posts (regarding oil and its specs and so on), it's hard to know what to think sometimes. I'm like you for the most part. If you don't do "something" and you have a failure of an injector or a few injectors within a few thousand miles of each other, is it because you didn't do whatever that "something" is/was? Or, is it just bad luck with some injectors whose "time was up" or did they just have more faulty components than other injectors? Was the metal used to make their parts just a "wee bit" less strong so instead of that part breaking/giving up at 350k, did it decide to give up at 250k?

I don't understand all the testing and analysis of certain things to be able to figure it all out.

But, what I don't "get" is whether or not there actually is a minimum requirement or standard that diesel fuel has to meet as far as cetane rating and other things that matter that I'm not even sure what those things would be. I am assuming that no different than gasoline that has to meet a minimum required octane level as described on their label, diesel has to meet similar requirements for diesel fuels. Otherwise, what's the point of putting anything on their label? Surely diesel fuel has to be held to a certain standard or minimum no different than gasoline right?

So, if this is true, then why do we in the USA apparently have so many problems with the diesel fuel?

As for my suggestion about the trip, I'll say it again that I think it's going to be next to impossible to get a trip like that with damn near exact same circumstances. You would have to get super lucky to have two to 4 back to back to back to back days or nights with the exact same temperatures and wind in the same directions and that virtually NEVER happens anywhere in the world. But, maybe a person could get lucky. I don't know. But also, is a 400 to 450 mile round trip journey twice over enough to prove anything? Like I asked, do we need to do one 400 to 450 mile round trip with one additive (we'll call it additive #1) and then two 400 to 450 round trips for a total of 800 to 900 with the new one (additive #2)? And then, do we do another trip with the first additive to see if the results go back to what they were prior to using additive #2?

And then, by the time you get all these miles put on which is about 1600 to 1800 miles, are the conditions going to be the same or has the weather and wind changed dramatically?

I doubt Ford or International will ever chime in either.

I just don't know what to make of additives. I don't want to be a believer in "mechanic in a can" type of stuff but it seems as if we're doomed for some sort of failure if we don't.

I will say that I have run my truck down to zero fuel pressure more than I should be admitting and definitely under the 45 PSI minimum WAAAYYYYYYY more than a person is supposed to. Like a few 200 mile trips bad. And, my truck still runs fairly well with the exception of the "other" issues going on. So, perhaps I haven't been left on the side of the road (yet) due to the additives doing their best to save my injectors and extend their life just a little longer. I don't know. For all I know, they are on their way out and they are just disguising themselves as "decent" running injectors so in a few thousand miles, I'll be needing to find a new set. Obviously, I hope that doesn't happen. Only time will tell.