Subaru discourages their use. See your Owners Manual.

• Never add any cleaning agents to the fuel tank. The addition of a cleaning agent may cause damage to the fuel system.

If you always use clean fuel from a busy and well-maintained station, a fuel system cleaner should be unnecessary. Fuel from vendors participating in the industry Top Tier program will already have significantly higher levels of cleaning additives, from the pump, than required by current EPA regulations.

 

Subaru discourages their use. See your Owners Manual.

If you always use clean fuel from a busy and well-maintained station, a fuel system cleaner should be unnecessary. Fuel from vendors participating in the industry Top Tier program will already have significantly higher levels of cleaning additives, from the pump, than required by current EPA regulations.

Then why does Subaru sell their own brand of fuel injector additive for fuel tanks?

 

If you are going to add anything to the tank, Techron every 15-20k miles as a cleaner to reduce fum and varnish in the fuel system. It will help reduce a small amount of carbon in the combustion chamber and valves; mostly the intake valves since gas flows over them.

High mileage and a good chance of heavy carbon, go with a bottle of Berryman's B12 in the tank at the same mileage interval. It's a bit more stringent.

What problems are you having? Most people with older cars don't look at this late in the car's life unless setting.popped up.

 

What problems are you having? Most people with older cars don't look at this late in the car's life unless setting.popped up.

My car is approaching 6 years old and 90,000 miles. These have been mostly freeway miles and and serviced every 5,000 miles with oil changes and tire rotations along with the 30 & 60,000 service. Now that I’m retired, the mileage will be less each week and mostly short trips to the store on country roads.
I was watching some videos on additives and there are many opinions on the subject.
I was just curious as I value this forums advice.

 

I only use the bottle of SA718 that Subaru supply me with each service - they do one during service, then and I add the other bottle into a full tank 6,000K's later.

 

Am I the only one who finds it odd that Subaru warns against using fuel-additives... but sells their OWN additive?

 

My speculation ... and it is only that ... is that the additive Subaru sells has been tested for compatibility with the injectors and other fuel system components used in Subaru vehicles. Other aftermarket fuel additives may or may not be compatible, but Subaru can't reasonably be expected to test them all, worldwide. I do know that many years ago GM had a problem with some fuel aftermarket additives degrading the insulation used on the solenoid windings of their port fuel injectors. YMMV.

 

I do a cocktail of Berryman B-12 and one bottle each of Super Tech injector cleaner/gas treatment once or twice a year. Cost's less than $10 total and makes me feel better at least.

 

 

As mentioned above, these two products are the Subaru approved additives ( see above pictures)

 

My late model Chevy suggests when not using top tier, and I seldom do, run a can of their fuel cleaner through every oil change. Rumor is it's just techron concentrate.

To me, might be a good idea, on a DI vehicle, when not using top tier, run a can of techron to the tank before you change the oil. Kind of an easy routine, but I could also be wasting my money.

 

I've always used BG44k. Expensive but a great product.

 

Whether it is just marketing or a club started be the elites of the industry, surprisingly some major chain gasoline stations do not distribute “top tier” gasoline. In the Midwest this includes Casey’s and Sam’s Club. It is believed that top tier gasolines have detergent additives that help keep fuel delivery systems cleaner. If this means that anything less than top tier fuel is used and fuel systems are allowed to become dirty with carbon build up, this is the opportunity for Subaru and others to sell you an additive. But not just any additive, apparently.

 

FWIW, I've run Sam's gas for decades w/o issue. But now I go to Kroger, because I usually get a buck a gallon off with their Fuel Points. No issues there either. 🤷‍♂️

 

With Direct Injection engines, you want a good fuel to keep gum deposits down in the injectors. You also want limited carbon development in the combustion chamber. As carbon increases the frequency of detonation goes up as the fuel contacts the heated carbon and ignites. Carbo comes from cheap fuels, the PCV system and low octane fuels due to constant fuel adjustments by the ECM when detonations occur.

SOA868V9165 is a Top Engine cleaner. It's to remove carbon deposits from the valves since they are not washed with Direct Injection systems. Sequential and Multiport injection systems sprayed fuel over the valves. DI does not.

When carbon builds up on the valves it will eventually cause cold start misfires and it affects the air flow across the valve.

 

FWIW, Autozone has a good deal on Techron Total Fuel System Cleaner.
$10 for a 20 oz bottle. For that price, it makes it a no brainer to try.