Wondering if oil and/or gas additives are helpful?

 

Pretty sure if they were required the owner's manual would state that.

If you drive where temps go way down, It is good preventive maintenance to add a container of dry gas *with isopropyl alcohol only) to your vehicle's gas tank every 2nd or 3rd tankful.
What does your owner's manual say?

 

Stay away from high viscosity additives!!! I lost my Sonata engine with 196K miles due to one of those. Keep using the original 5W -20 oil. If you prefer go with synthetic 5W-20 grade oil.

 

Most new vehicles come with synthetic oil in them already.
It would be a good idea to verify that with your local dealership.

I have found that if regular non synthetic motor oil was used and the engine has high mileage on it , switching to full synthetic can create some leakage problems.

Having seen that on a few occasions , i would hesitate switching to full synthetic with an engine that has high mileage.

I don't see much advantage using additives if not required.

 

Oil additives are snake oil. "Oil flushes" on the other hand sure can be helpfull depending on what your trying to acomplish with them ? for example do we have a Oil consumption issue where its useing Oil? if PCV Valve has been changed and made no difference then theres a chance that Oil control rings are stuck. a strong concentrated flush like BG EPR might work at loosening up Oil control rings and useing Valvoline Restore & Protect will further help clean out the engine although that Valvoline R/P is not a additive or flush it has the right cleaning detergency chemistry additives already mixed in to safely clean any internal engine out. now if there are no issues with your engine than additives are not needed at all. useing a good known brand of oil that's spec'd for your engine with the correct viscosity is crucial and really thats all that engine needs.

Fuel additives again depending on what your trying to acomplish is the fuel mileage decreasing is there some engine roughness hard starting than normal? then yes i would use a strong concentrated cleaner something like berryman's B-12 fuel system cleaner or BG 44k also works very well in some cases you may need to run 2-3 tank fulls to really clean the fuel system out.

and there after use a top tier fuel with plenty of detergency like Shell or any top tier fuel in your area. for the most part of a normal running engine there are no need for fuel additives top tier fuel is really all that's needed unless again there is an issue as mentioned above.