Great question! The “short” answer is as follows. Berryman B-12 Chemtool Fuel System Cleaner (part #0116) is a great routine maintenance product based on 100% strong solvents—we call this H.E.S.T.—and is very effective at keeping carburetors, injectors, and intake valves clean. Once you really start to get a lot of buildup in the system, though, combining HEST with targeted detergency becomes necessary for cleanup. Our B-12 Chemtool Injector Cleaner (part #1112) cleans everything from the gas tank to the fuel injectors and to some degree the intake valves. Especially dirty Intake valves require more detergency, though. That’s when it’s better to use B-12 Chemtool Concentrated Intake Valve & Injector Cleaner (part #3012), which cleans everything the 1112 does but formally adds injectors to the list, too. Dirty combustion chambers can lead to hot spots on the piston, knocking/pinging, octane creep, and higher emissions; cleaning combustion chambers is Herculean task for a fuel additive, though, and requires specialized detergents. (That’s why so few products make combustion chamber cleaning claims!) Fortunately, B-12 Chemtool Total Fuel System Clean-Up (part #2616) is up to the task. It is our strongest gasoline fuel additive and thoroughly cleans the gas tank, the combustion chambers, and everything in between. So depending on which components you’re trying to clean, you may be fine with your purchase or you may need to consider something a bit more aggressive. Also, if you have a vehicle with an unknown history of maintenance or with known maintenance deficiencies, i.e. when you’re in doubt, then just use 2616 because it really does do it all. Good luck!

Thanks for the reply. Another question I have is if Total Fuel System Clean-Up(#2616) can clean the combustion chamber, then it sounds like its also doing the work of Total Combustion Cleaning Kit (#2610) and doing this step would not be necessary. Is this correct? I ask because I had just acquired a Lexus RX330 with 188K miles and by looking at the service receipts, only a fuel additive was added at 100K and I'm trying to figure out the best way to service this car with your products. I have #0116 in the tank now. What else do you recommend?

The 2616 is a great product for someone who just wants to put something in their gas tank the next time they fill up. However, 2610 is a phenomenal combustion chamber cleaner and excellent at combating spark-knock, octane creep, and high emissions. It’s fairly easy to apply, too, but some people just aren’t comfortable using the kit. All that said, if you have a high mileage vehicle with a spotty history and aren’t afraid to loosen just a couple screws, I would strongly suggest considering our Professional 3-Step Fuel System Maintenance Kit (part #2630). It combines our B-12 Chemtool Air-Intake Cleaner (part #2209), the 2610, and the 2616, and it has an instruction DVD, too. Basically, you get the best of everything!