cyrnel

Right before an oil change...

Park outside. Pull the plugs and pour ~1oz in each cylinder. Cover the plug holes with a rag(s) and bump over the engine ever so slightly. Just a tap. (distributes the cleaner around the rings) Replace plugs and let sit at least a few hours. No driving. Next morning, warm the engine (still no driving) and draw dose in via vacuum hose or pour it directly into the throttle body - without stalling engine. Expect a cloud. Let it idle for 5-10minutes, shut down, change oil & filter. Really. You don't want the seafoam in your crankcase for any length of time.

Pouring it into the gas tank will help clean your fuel system, intake, and might do a bit for the combustion chambers. It'll also drop octane a bit which you may feel as a performance change for the better or worse.

Pouring a small amount into each cylinder and allowing a soak clean the compression rings and can make a big difference on higher mileage cars.

It all depends on the condition of the vehicle. If the car is recent or in great shape you may not notice any change at all.

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There are a vast number of people who are uninformed and heavily propagandized, but fundamentally decent. The propaganda that inundates them is effective when unchallenged, but much of it goes only skin deep. If they can be brought to raise questions and apply their decent instincts and basic intelligence, many people quickly escape the confines of the doctrinal system and are willing to do something to help others who are really suffering and oppressed." -Manufacturing Consent: Noam Chomsky and the Media, p. 195