Are fule additives like Gumout Fuel Injector/Carburetor Cleaner and Marvel Mystery Oil, Gas Treatment help for a car? I have a Chrysler 300, 2010
Why does your car need help?? If it’s not broken, don’t try to fix it. Most of these additive products offer no benefit.
Not for your 2010 Chrysler 300 !!!
You have a brand new car. There is no reason to use any of those additives.
After 10 years/100k miles you MIGHT need some of that.
Using as often as you can only Top Tier Gas (linky below), will most likely ensure that you’ll never need to buy those additives.
They are products looking for a problem. If you don’t have a problem, you don’t need them. If you have a problem, likely you need a fix, not any of the above magic fixes for non-existent problems.
When my cars are 3 or 4 years old, I add a can of Chevron Techron or Seafoam once a year as preventive maintenance. Nothing like this is needed on a new car.
Ed B.
Additives are needed when things get older. I didn’t use any additives until recently–now I have to use Geritol. Your Chrysler does not need these automotive Geritols.
I have noticed that the additives are most often used regularly by people who are somewhat fastidious in their maintenance. These people enjoy many years and miles of reliable service from their cars and credit the “special additives” with some of their good luck. For some reason Mystery Oil, Techron, Sea Foam, and Lucas are the current front runners for the additives folks. 40 years ago it was Bardhal, Rislone, STP and Wynns Friction Proofing. But regardless which product and which era the fastidious always seem to trip the clock(100,001 mi) and keep running.
Additives are only good for squeezing a bit of extra life out of a worn out beater, and even then they don’t usually help.
The fluids in your engine are provided by all name brand suppliers with all the detergents, anticorrosive additives, viscosity modifiers, and enhancements that your new engine and drivetrain need to enable the engine to outlast the car. The American petroleum Institute and the Automotive Society of Engineering mantain labs and spend copious amounts of research money to develop these products to their utmost in effectiveness. You need not add more to what they’ve already done.
The key to enhancng their effactiveness is not to add to them, but rather to change them and their filters in accordance with your manufacturer’s recommendations and with the proper fluids recommended by the manufacturer. And to treat the drivetrain with respect…don’t abuse it or pound on it.
To answer your question directly, yes, fuel system cleaners, like Techron, or Berryman’s can and will actually clean off deposits from intake valves and piston crowns. I have seen this first hand in car engines, and in motorcycle engines.
As for your brand new Chrysler, it is not going to need them for quite a few miles.
At the earliest, 30k miles.
You shouldn’t ever need to add Marvel Mystery Oil to the engine oil during the life of your car, as long as you change the oil and oil filter every 5k to 10k miles, depending on your over all driving habits for the car.
Enjoy the car!
BC.
The owner’s manual for my Mazda states to never use those kind of additives in it, ever
Gumout REGANE COMPLETE, Amsoil PI, Techron Concentrate …all good products with PEA to keep fuel residuals and combustion chamber deposits in control. Every 6 months would be a good idea especially if you’re a short trip geezer like we’re all turning into. Fuel residuals get to accumulate on injector nozzles and then valve backs and then pistons. It was never an issue of merit until the vast majority of baby boomers started heading only to the senior center as they got empty nested and retired. It doesn’t happen to soccer parents that are still running themselves ragged commuting a million miles or running all over “for the children”. 
Many who confidently diagnose an engine with piston slap are actually hearing CCDI (combustion chamber deposit interference). It’s a well documented effect and has an onset and retreat that 100% parallels piston slap.
For those not yet so educated. Texaco/Chevron used to have pages on this very topic, but they’re no longer active. Just put Combustion Chamber Deposit Interference in google http://dspace.mit.edu/bitstream/handle/1721.1/17505/48747197.pdf?sequence=1
Or, one could give it an “Italian tune-up” every so often. I done this on my Civic awhile back when it was idling kinda rough and it worked wonders, and I only used a tiny bit more fuel than I normally would have