Gas treatments, additives, cleaners...do any of them work?

My grandpa swore by Gumout bottles and when I first started driving in the Navy in the 80's he always had a bottle or two as gift when I came home to visit. I remember high school friends liked 104+.

I've heard arguments for and against gas treatments, fuel system is closed loop and doesn't need it, gas is already clean, some gas isn't best quality, etc etc...

Any viable knowledge on such things? I keep wanting to dump a bottle of something in Subarust, at 150k miles, but just can't decide if they're worth it.

I run seafoam at every oil change. Don't know if it actually does anything, but I never have fuel system problems.

Way back in college, I worked for Chevron, where we tested them. Yes, they worked.

But I only saw the actual Techron additive being tested- which did work. Our work was more on the core fuel additive, and at the time, Exxon had the best one (which they actually bought from Chevron, who, then, couldn't use it...)

Bear in mind, this was almost 30 years ago, detergent package laws have changed, as have the ability to make interesting chemicals. I'm sure things have progressed.

Man I almost accidentally canoe'd on instinct here. Realized my manager wasn't within ear shot so I caught myself.

I dont really care for them but earlier this year I had an old Mercedes with Bosch CIS fuel injection that had a slight miss at idle. I bought this guy

BG44K

It transformed the car. This is not the type of additive you use regularly, but should only use once or twice a year tops.

Its expensive but it was well worth it on a high mileage engine.

Techron is the only one that works. Keeps the valves clean, I'm fairly certain this is Shells nitrogen enhanced fuel since they are now owned by chevron. Costco treats their fuel with techron.

As far as gas treatment goes, you can't add a small bottle of snake oil to bad gas and make it better, you just get a lighter wallet and a fuller tank of bad gas.

Octane booster is more smake oil. The marketing dweebs have taught everyone the more octane = more power. But it is actually the opposite. In fact too much octane will cause a loss in power.

To get a power increaSE you have to change the motor to take advantage of the fuel.

Many times I have seen family, myself or friends get a "misfire on cylinder 3" code and a bottle of injector cleaner was the cure.

The Chevron stuff worked for me. When I got the X type it had a stuck injector. I let the tank get to 1/4 and then put two bottles in and drove it about 50 miles and then let it sit overnight. The next day the injector issue was solved.

My current understanding from friends in the industry (an understanding which is about 5 years old since I last thought ask them about this) is that Techron is the industry standard Top Tier grade core additive of nearly all U.S. pump gas. If it isn't rated as a top tier fuel, it might not have Techron in it. That said, the Techron concentrate (at AutoReillyVance, etc.) is probably the most effective if you want an occasional cleaning boost. I was told to use big bottle, even in cars with a smaller fuel capacity.

I feel like Seafoam has helped my various derelict vehicles in the past, both in the oil and in the gas tank and sucked through a vacuum fitting. However, the placebo effect is real so without instrumented tests I don't know how to back that claim up.

I had a Volvo 850 that was neglected when I got it. It ran very rough. Sea foam helped smooth it out but MAF cleaner and new inter cooler boots helped a lot more. If I'd done the MAF and boots first I don't know if the sea foam would have helped at all.

Oh, and here is my problem with "Techron is the only one that works:" if one cleaner works then it's possible for another one to work. It's unlikely that there's one specific chemical formulation that would work well while every other one has no benefit. I could see one being the best - for now - but not being literally the only one that works. That makes no sense.

Any injector cleaner that contains PEA will work as a cleaner. Of course, on cars that don't sit much and are generally fed clean fuel, things seem to stay pretty clean without help.

I know lots of people with older fuel injected cars that swear by Marvel's Mystery Oil to keep pumps and injectors quite.

Seafoam through the intake, followed by an Italian tune up has worked well for me a few times, but I think if the Italian tune up had been done sooner the seafoam wouldn't have been needed.

How has e10 fuel changed the gas additive game? Ethanol is a solvent, and was an ingredient in many past additives.

I've cleaned carbon off pistons with Seafoam and a toothbrush - and I've cleaned gas varnish out of old carbs with gumout or denatured alcohol but I don't normally add things to my gas or oil. If I buy a sludgebucket that sat for a long time I will flush the oil with ATF for 30 minutes and then change it, and run a tank or two of Techron thru it but I've never poured a can of Marvel Mystery Oil into anything.

HappyAndy wrote: How has e10 fuel changed the gas additive game? Ethanol is a solvent, and was an ingredient in many past additives.

It made drygas irrelevant, as the ethanol already in the fuel does the water absorbing job now. It also does have some mild cleaning effect.

For those talking about Marvel Mystery Oil, it's not much of a cleaner in fuel, but it's a light enough oil that it can be safely used to lube things. I've un-stuck a slightly sticky fuel sender float with it before (by dumping significantly more than the recommended dosage into the tank).

bentwrench wrote: Techron is the only one that works. Keeps the valves clean, I'm fairly certain this is Shells nitrogen enhanced fuel since they are now owned by chevron. Costco treats their fuel with techron. As far as gas treatment goes, you can't add a small bottle of snake oil to bad gas and make it better, you just get a lighter wallet and a fuller tank of bad gas. Octane booster is more smake oil. The marketing dweebs have taught everyone the more octane = more power. But it is actually the opposite. In fact too much octane will cause a loss in power. To get a power increaSE you have to change the motor to take advantage of the fuel.

Not so much looking for a magic cure for E36 M3ty gas. I'm thinking this sorta-high mileage rusty Subaru might benefit from something that cleans injectors, if such a thing really exists.

Two additives I use:

DieselKleen in my W123 to replace the lubricity that used to be provided byt he Sulphur in diesel. Made the engine idle much more quietly and smoothly, gotta believe it'll be good for the long-term health of the engine, too.

Sta-Bil Marine in the gas for my older cars (pre-1980's) and lawn equipment. Supposedly makes the fuel last longer and quells the Ethanol's appetite for destruction.

Just recently read about the whole Top Tier Gas thing and additive packages. Now I'm making it a point to only buy gasoline from name-branded station.

I used to work for Amoco Oil, now BP and one job I had was scheduling the delivery of the gasoline additive we used to each of the 150 or so terminal locations we used. During the time I handled this we purchased a custom additive made to Amoco's specs from Chevon/Ornite, a division of Chevron. Most likely also the division that makes Techron.

The stuff works. The EPA has set a minimum level of "detergent" additives in all gasoline but almost all major brands add more to their mid-grade and premium fuels. It's not a bad practice to top off a 1/2 tank of regular with the top grade to get the higher level of this detergent additive.

Lucas Oil Company also makes a good fuel additive. Since I DD a diesel I always add a diesel fuel additive and a lubricant to the fuel. Marvel Mystery oil is something I use. It's sort of a 2 cycle oil in that it burns clean but it's not as heavy as a regular 2 cycle oil.

Even a quart of used motor oil in a full tank of diesel will solve the lubricity issues. Many recommend just trans fluid, others use 2 cycle oil. Not sure if it is still an issue with the new common rail injection, I know it makes a difference with the old pump style.

Clean fresh fuel is best. It's best to discard old fuel than to try and use it. It tends to sticky up valve stems, to the point of actually not letting the valves close and causing chaos with the valve train.

bentwrench wrote: Even a quart of used motor oil in a full tank of diesel will solve the lubricity issues. Many recommend just trans fluid, others use 2 cycle oil. Not sure if it is still an issue with the new common rail injection, I know it makes a difference with the old pump style.

There was a test done somewhere (search online) that showed lubricity of low sulphur diesel vs the old diesel, and LSD with various additives. It also calculated cost/ gallon. One of the "additives" they tried was 2-stroke oil and also regular motor oil (though not used oil, new). The Diesel Kleen gave lubricity very close to regular old diesel (pre LSD) and also gives a bit of a bump of cetane, which motor oil doesn't do. It was within a few cents per gallon of the price of using motor oil, too.

I'd be scared of running used motor oil through my injector pump.

seafoam is my go to. I have seen it work its magic several times.

I too have seen a comparison where Techron was the only one that showed significant differences in the study. Everything else looked like you just ran a few tanks of clean gas in it.

I did notice that SeaFoam cleaner was not used.

This isn't saying that other brands can't work, just that Techron, and how it was tested, does work and much more so than primary competitors.
So I guess of the normal "pour it in the tank" kind, Techron is the stuff.

edizzle89 wrote: seafoam is my go to. I have seen it work its magic several times.

What sort of magic? Quantify please.

In the old days, gasoline would go bad, gum up an smell to high heaven .

So some of the additives worked and were needed.

Todays gasoline does not seem to do that, plus they have detergents added.

Our sealed systems seem to help too.

Remember when we had to add Dri-Gas to the tank, esp. in winter. to absorb the moisture? Ethanol takes care of that.