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Fuel additives how often should you use them

I am planning to start using seafoam in my gas and oil ,how often should you a add it an how much.The label isn’t to clear about it.

Why are you planning to use an additive? Are you having a problem? Frankly few cars need or will benefit from additives.

That said, I would suggest starting by reading the car’s manual to see what it may say and second try reading the instructions on the can.

I generally use one bottle of a diesel additive to my VW diesel every year, at the beginning of winter to provide some anti-gel to prevent problems if we get a early cold spell. In over 45 years of driving, that is the only regular use a additives I have used and I have never had a problem that could have been eliminated or reduced by any additive I know of.

Modern cars, oils fuels etc. seldom need special help.

As Joseph stated, modern cars, oils, fuels, etc, seldom need special help.

Unless you have a specific problem that you’re trying to get an additive to address, wouldn’t you rather not waste your money?

I add a can of Seafoam or Chevron Techron once a year or so on my cars and trucks as preventative maintenance. My rule of thumb is to add roughly 1 oz of additive per gallon of fuel.

Ed B.

I do the same about every 6 months. I have no idea if it does any good, but it doesn’t hurt at that frequency.

If you were to call the folks at SeaFoam they’d tell you to use it as much as you want (not surprisingly).

Ijust bought my car an when I changed the air filter there was a lot of black stuff in the throttle body an thought Ineeded to try an clean the rest of the motor out.Idid clean the throttle body out an it definitely helped.

Definitely helped WHAT?

The throttle body on almost all cars is dirty to some extent. The dirt is only a problem if it makes the throttle stick or causes some other driveability problem.

So what did cleaning it help?

I’ve used Seafoam for forty years. And if you want to add it to the engine oil to remove sludge and clear out the PCV system, pour half the can into the oil and the other half into the gas tank. We call this the Minnesota Tune-Up. This will not harm the engine or fuel system in any way. I apply the Minnesota Tune-Up every six months.


When the next step is sending your car to the scrap yard.

I think you find in 99% cases that pouring the equivalent amount of bottled water into a full full tank does the same thing.

When I was a kid, I heard the old timers talk about adding mothballs to the fuel tank of the Model T to increase the octane. One could then set the manual spark advance control (the spark advance was on the steering column) and the Model T would really fly–maybe as fast as 50 mph.

I doubt that the mothballs really did much good back then and I am certain that with today’s fuels, the additives do even less good today.

Agree with posters; today’s gasolines have quite a few additives already in them. We’ve driven cars to over 300,000 miles without any additives other than the odd bottle of “gasline antifreeze” in very cold weather.

Years ago I recommended an additive called “Karbout” to my father-in-law. He only did short stop and go trips in his carbureted Buick and ran a very rich fuel mixture. Today’s computerized cars with fuel injection don’t have those problems anymore.

If you are having problems with your fuel induction system, look for the real causes and fix those.

Modern cars need no additives beyond those already in the gasoline. I don’t even use winter additives. Since today’s fuel systems are high pressure and completely fluid filled all the way from the gas tank to the injectors, with no opportunities for ice crystals to form, drygas is no longer needed.

I do, however, use carb cleaner or injector cleaner in the gas I use in the lawn mower & snowblower. It really helps there.

the pick up speed and it pulls alot better

Think clean air, clean gas and clean oil.

If you use a Top Tier gasoline, a top grade oil and filter (like Mobil 1 synthetic) and change it regularly and replace your paper air cleaner every year or switch to a cleanable/reusable one like a K&N, you shouldn’t need to add anything to your oil or gas. The detergents in the gas and oil will keep sludge and varnish build up to a minimum. If you have direct fuel injection, a 20 oz. bottle of Chevron’s Techron to a tank-full of gas once or twice a year (depending on mileage) will help get rid of any build up in the injector nozzles. It is very important that the injector nozzles shoot an even spray.

Happy motoring

Does it have to be bottled water or can I use tap water??

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Unless the manufacturer specs it or under extreme conditions synthetic oil is no big deal.
Independent tests have shown those K&N filters let more dirt in.

Get online and access TSB’s for ANY (well just about) GM vehicle and read what GM says about top tier gas and fuel injection cleaning, it will give you some perspective on fuel system additives.

In my boat it is with all gas fills, in my cars about every couple of years I will splurge and put some in just for good luck. In the boat it has been an experienced necessity, in the cars I have no conclusion but do it anyway, superstition or real benefits I don’t know but that and providing basic maintenance for the cars I have had have never had an injector problems. Keeps tigers away too, and I have not seen any of them either.

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I’d use something like GUMOUT REGANE COMPLETE fuel system cleaner every 6months. It uses the same stuff as Techron.

Skip any solvents in the sump. Oils are great in terms of deposit control. If you develop a problem, you weren’t changing it often enough. Consider using Auto-Rx ( every 50k or so. All of your solvent type stuff usually acts as a thinning agent for the host oil. Auto-rx is composed of 3 esters, the main one being the same as Red Line’s base stock. The worst it can do is turn your oil into a more complex and expensive oil. The esters have a high polar attraction to metals. It basically displaces deposits from where they’re residing.

Found an interesting article on today’s gasolines and the fuel additives added:

Looks like most top tier gasolines already have it in there.

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