Fuel injector cleaners do not really go bad. But, if they sit for a long time you should shake them since some additives will decepate and get seperated from the liquid can/plastic they are stored in.
Note: It might not be able to go “full strength” anymore.
So, can fuel injector cleaners go bad? If there are no expiration on it, and its unopened, then it should be ok. We recommend pouring it through a strainer before you put it in your tank too to be double sure there are no solids in it.
Does Fuel Injector Cleaner Expire?
As far as the bottles are sealed up, I would recommne dusing it. The worst case scenario is that you have the better volatile constituents that are missing and have heavy parts and they wouldn’t have harmed the engine once diluted in the tank.
Is the shape still in its original? That’s even better! Many additive bottles contain aluminuzed foil seal that prevents oxidation. So, you should always use injector cleaner at the gas pump and add bottle, then a whole fillup.
To get the best results, we advice driving without topping off until you get close to E, most benefits are had on a long road trip that burns that tank of gas in one stretch.
Optionally, you change fuel filter before using the injector cleaner as well.
ALSO SEE: How to Use Liqui Moly Fuel Injector Cleaner?
How Long does Injector Cleaner Last?
Specifically, a single bottle of injector cleaner can last 1,500 to 3,000 miles. A lot of drivers use fuel injector cleaners whenever they get an oil change, so it is simple to remmeber.