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What's the difference between gas cleaner, carburetor cleaner, injector cleaner?

Walmart sells its gas cleaner or injector cleaner for 97¢, injector & carburetor cleaner for $1.88; the prices for the STP are similarly proportional; the prices for the Gumout brands inverse. I’m no expert, but I always thought these were the same stuff with a different label. They list the same ingredients (‘petroleum distillates’ - not specific) and promise to clean similar surfaces.

When I re-built my carburetor earlier this year, the first time in 30 years, it looked clean. I didn’t even see varnish. I have used gas cleaner or carb cleaner about every year, but I expected some gunk to have accumulated.

If you use Top Tier gasoline, you don’t have to use those additives.

Most gas stations sell Top Tier gasoline.


You don’t need these additives unless you’re trying to deal with an operating problem on an old engine.
And you don’t need Top Tier gasoline either. I’ve run engines for hundreds of thousands of miles without problems on regular gasoline of the octane required by the owner’s manual.

One thing I do is to avoid stations that have very little business, and I fill up when the tank reaches half empty. That mixes whatever gets pumped in with the known good gas that’s in there. I have no way of knowing if it’s actually prevented any problems, but I’ve never had any fuel problems so I’ll call it superstition. But it’s worked for me for over 1/2 century.


if you drive 6-8-10-cylinders, TSB, then I can absolutely agree that likely you would notice not much difference if you engine is in top performance or not

my experience with “top tier” gas comes from my history running exclusively 4-bangers, mostly in 1.8-2.5 liters range… other there you really count every horse in a stable and feel if your engine is not at its peak

anyways, until I started to use “top tier” regularly, I would need to clean injectors every 2-3 thousand miles or I felt that engine is not performing. every time I would run additive through it, I would feel power surge… once Costco started selling “top tier”, I’ve noticed I do not need to use additive anymore, it kinda 'automatic" now

will you damage your engine NOT running “top tier” - DEFINITELY NOT

do you feel power drop not cleaning injectors on cheap gas - DEFINITELY YES

this is only from y experience, but somehow (?) it happens to match the marketing point as well as manufacturer advice

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I didn’t say I had to use those additives. I don’t say that they do any good. Considering the higher price of Top Tier gasoline and the inconvenience and expense of using a TTG station, 97¢/year for a bottle of additive is a bargain; 97¢/fill-up would be a bargain. I asked a technical question: what’s the difference between the additives?


from my prior experience, the cheapest one worked as good as a mid-ranged priced one, so likely the answer is “this is purely marketing to target all and any customers to get as much out of their pockets as they feel comfortable” :slight_smile:

The additives may be the same or some may be more concentrated. Sometimes you have to study the label’s teeny-tiny print. But, gasoline is definitely different, stay away from cheap second tier gas. First tier gas has the additives.

Looking at the safety data sheets of Gunk fuel injector cleaner versus Gunk fuel system treatment, the difference appears to be that the fuel system treatment has a solvent* in it that the fuel injector cleaner does not.**



Isn’t it frustrating that even a regular in this forum cannot get a direct answer to a direct question from other regulars?


So, that’s the definitive answer. Are they different? Well, yes. At least the Gunk brand is different.

Does it matter for your purposes? That requires a chemist’s opinion, and that sure isn’t me.

While I can understand completely the curiosity that makes you ask this question, there’s probably never going to be an answer that completely explains everything.

It’s like when someone cuts in front of you on the freeway, and then goes 55 in a 70 zone. What were they thinking? You’ll never know.


I tried to compare Techron fuel injector cleaner to Techron fuel system cleaner first, but I could only find one online. Maybe they’ve stopped selling two products or I am mis-remembering that they ever did.

If I want fuel cleaner I just pick up the one that says fuel cleaner, if I want injector cleaner I just pick up the one that says injector cleaner, do I care what the difference is , not at all.

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In addition if I need a maf cleaner I buy one, if I need a throttle body cleaner I buy one. I have heard throttle bodies coating can be compromised by using the wrong cleaner,

Thanks for the references:

	'Motor Medic Fuel Injector & Carburetor Cleaner'

   Chemical name                        CAS number     %              
   Petroleum Distillate Aliphatic      68476-34-6                 70 - < 80
   Kerosine (petroleum)                   8008-20-6                 20 - < 30
   NAPHTHALENE                         91-20-3                    < 0.3

' Motor Medic Concentrated Fuel Injection System Treatment'

   Chemical name                            CAS number                  %     
   Petroleum Distillate Aliphatic        68476-34-6                 60 - < 70
   Kerosine (petroleum)                     8008-20-6                 20 - < 30
   Solvent Naphtha (petroleum), Light 64742-95-6                  1-<3
   NAPHTHALENE                             91-20-3                    < 0.3

10% less petroleum distillates, 1-3% more naphtha - what difference does this make? Aren’t they all supposed to remove the residues left behind by burning or evaporating gasoline?

I’m not sure you can do more with the percentages than say that the two chemicals are similar. I think the spread in percentages of each ingredient is the prevent just anyone from making an identical chemical. It does not show the range of ingredients that could be in any given batch.

I wish I knew. I don’t have the scientific background to answer. I can only speculate that the additional solvent in the fuel system cleaner removes varnish left behind by ethanol and anything normal detergent in the fuel didn’t prevent or remove.

We have a Costco near us (which is Top Tier), and their gas is the same price or cheaper than non-top tier stations around. Top Tier isn’t always more expensive.


In my neck of the woods, Costco top tier fuel is even cheaper than Arco, and that’s saying something

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Are you planning to put some product in the gas tank to clean the fuel system? I expect all those product will clean the fuel system more or less equally well. Some of them may possibly not be fully compatible with the materials and sensors used in your engine, fuel tank, and fuel lines. I expect that’s the main difference, their compatibility matrix. Suggest not to add any of them unless there’s a clear reason.

Long time ago, when Costco was selling non-TT gas, I’ve tried filling up there few times, and every one of them my 2001 Focus would become sluggish and capricious to start in the morning, so I was returning back to Exxon and avoiding Costco.
Car had under 30K miles on it BTW, so it was definitely not about engine.
Once Costco transitioned to TT, I was always filling up there and so far I’m a happy camper.

Well, if Costco carrying Top tier branded gas is the difference, that settles it: it’s in your head.

Costco has, as I understand it, actually BEEN “top tier” for a while now. SOMEBODY owns the “rights” to the “Top Tier” slogan, and for the longest time, Costco felt that “paying for a slogan” was anathema to their mission statement.

At some point, however, Costco caved to popular demand, and started PAYING for the right to call their gas Top Tier. (The SAME GAS they had been selling for a while, mind.) So, if you noticed improved performance after the branding switch, we’ve ISOLATED the phenomenon to “inside your head,” as your car can’t be swayed by marketing.

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