There is nothing in Seafoam that is going to increase your MPG
I did a google search for "Seafoam, Mileage" and got as many people claiming a drop in mileage as an increase..................
The only valid test would be a test on several vehicles, operated on a dyno in tightly controlled conditions conducted by an independent lab . (Seafoam would never allow this kind of test)
No one doing a "test" on their own vehicle can produce meaningful results. It's just not possible.
It all goes back to that "feel-good" thing.
And I totally get that!
I think seafoam is a personal choice. I did some testing with it and found on a cost basis it was a wash between using it or not. I tried it in a high mileage fuel injected vehicle that was getting 18.5 mpg, I added seafoam during a fill up and got a couple more mpg's. I then filled up again without it. Mpg's fell back down to 18.5mpg's. I did this a couple more times and got the same results. If I do the math with the cost of the fillup and the added cost of seafoam compared to buying a couple more gallons of gas results in the same cost. Seafoam did make the engine run a little better, i figure it is because of something in seafoam. I question whether It really cleans anything in the fuel system because the mpg's always dropped to the original mpg's. If it cleaned the system I would expect an overall improvement after its use.
Hmm.... I may be using different math........... Seafoam recommends using 1oz per gallon of fuel for "maintenance" (2ozper gallon for "cleaning") and says there's no upper limit in the amount you can use........
Many people drive 20,000-30,000 miles per year.
If you got 18.5mpg and drove 20,000 miles, you'd use 1081 gallons ...
Using Seafoam's own "maintenance" recommendation, you would need to buy 8 gallons (actually 7.6 gallons required but if you buy only the additional 0.4 gal, you would pay more for the smaller container)
8 gallons at the best price I could find would cost you roughly $424 ........ if you only used 7.6 gallons the cost would be $402 (if you were "cleaning" for an entire year, [for 20,000 miles] it would cost you roughly $800!!!!)
You said you got a "couple more MPG" for most of us, a couple is TWO......... (2) MPG increase...........
If you got 20.5mpg for 20,000 miles, you'd use 975.6 gallons of fuel. (A 105.5 gallon DIFFERENCE)
At $1.60/gal, you save $168. At $2.00/gallon you save $211
since that 7.6 gallons of Seafoam costs $402 Gasoline would have to cost $3.81per gallon for it to be a "Wash"............
Even @ $2/gallon for gasoline , I don't think it's worth an additional $402(or $800 if you're cleaning) to get 2 mpg The numbers don't crunch.
I couldn't find a claim on their website where they claim a mileage increase (they probably know better........someone would actually DO a "real test" and start a class action) ...........AND after doing a search for "Seafoam + MPG" there was as many claiming an increase as a decrease.......
So back to the OP's original question.
Will it hurt to run it every fill up? ...........I need some more opinions.
According to the SEAFOAM FAQ, NO.
https://seafoamsales.com/faq-ask-jim/
And according to Seafoam
Can I add too much Sea Foam to fuel? no
But I would be VERY suspicious of someone saying that when they sell it! **** YOU use more, THEY make more money!!****
So, in my opinion, to reiterate, you're wasting your money using the stuff!
Regards,
Rick