LS WON

With the above additives from Chevron, can putting in too much of a good thing be bad for car with either of these two products?

Flame Red

Years ago when I had a car that had a chronic carbon buildup problem, I would use Techron a few times a year. The directions at the time said that one should treat the gas with the tank of gas before a scheduled oil change. I am assuming that the carbon buildup might partially get into the oil. Don't see that anymore. So perhaps if you used to excessively, one should consider changing the oil?

AORoads

We're not the ones who chemically formulated and (hopefully) tested either one to see the corrosive or negative effects of too much. For that reason, altho two bottles of either type of cleaner may not be bad, it could be, and more could be worse. After all, if it wasn't bad, why wouldn't they just write on the bottle: "Use one per 20 gallons, or more bottles if you wish to do an even better job." It'd be a good way to sell more product.

jimmie jam

Exactly. More is not always "better"....except when taking about giving me cash

Gearhead Jim

The label on GM/ACDelco Fuel System Treatment Plus (re-packaged Techron, it seems) says to add one bottle to 20 gals of fuel, but also says "minor overtreatment will have no adverse effects on engine. Add to fuel tank at every oil change. To achieve maximum cleaning benefits, use once every 3,000 miles".

Note that the current wording does not say anything about adding it before the oil change, or after. Certainly, every 3k miles would not come just before each oil change.

I always use Top Tier gas, and add the Treatment once per year (15k-20k miles).

toxin440

I usually try to put Chevron or Shell in my Z. Since my vette has been sitting for 2 years (back on the road in 1.5 weeks WOOHOO)

I will for sure be running a bottle of techron through my car. The fuel was treated for storage, still runs like a champ (did a test run and check of all systems over xmas) but after I burn through the rest of the old/treated gas in the tank I'm going to fill up with some Shell or Chevron and run a bottle through it. For a few bucks it can't hurt.

carpe dm

"Use as directed".................... If you have too much, just add fuel when you are 1/4 th down or so, to dilute the mixture. A little extra should be no problem.

LS WON

I have to check instructions again as I remember on the ProGuard Fuel injector cleaner it says to use every 3,000 miles unless that has changed.
But there is also the other Chevron Fuel Concentrate that cleans up the whole system which comes in 10 ounce, 12 ounce and 20 ounce bottles. It just says it may take more than one bottle to fix problem. I am wondering what if you put in a bottle of the 20 ounce with half a tank of gas to make it even stronger if it works out that way.

LS WON

Which bottle the ProGuard Fuel injector cleaner or Fuel concentrate?

Vette5.5

2-3 times a year, should be fine for most gasoline additives. As mentioned, stuff isn't really designed to be in the tank, all the time.

Gary '09 C6

I also alternate primarily between Chevron and Shell. I add a large bottle of Techron concentrate about twice per year.
toxin, good for you getting your Z back on the road...!