LexVan

This has been debated more than 1 million times. Go in search of expert opinions from the Porsche gurus Steve Weiner and L&N.

The simple fact is if you're going to use a fuel system cleaner would you rather add it to the tank of gas one day before your oil change or one day after your oil change if you are only going to use it once per year?

Chrono

According to me, if an injector happened to be leaking - because it could not shut all the way - because its dirty - then the small mount of gas being introduced to the oil might be an issue*. However, if a fuel treatment clears the gunk so that the injector now closes properly, where did the gunk go? It "seems like a good idea" to change the oil after using gas treatment. And why not?

*A Blackstone report will reveal if this has been happening.

kosmo

Simply put there are additives in modern oils.

Too much fuel additive can break down the efficacy of the oil.
So its best to not over use fuel additives.

In fact the techron bottle says not to use more than twice a year.

Chrono

Major respect for Chevron for saying that.

Now if we can get McDonalds french fries to say "do not exceed two servings a week".

LexVan

Hmmmm, not the bottles I have from Walmart that treat 15 gallons of fuel (10 ounce bottles). They have a banner wrapper that says "use every 3,000 miles to maintain a clean fuel system".

Hyper997SS

I use NF octane boosters and cleaners in my 997S supercharged all thr time for over a year now. Μy engine is unbelievably smooth and the response is greater than even before.

Mumbles

Again its one of those grey areas that I personally don't think that it'll do any harm adding a FI cleaner every few thou.
Any help to keep the injectors clean and possibly delaying an engine maintenance service down the road.

One thing that always amazes me with these DFI engines is the amount of carbon residue on my exhaust tips, like where does all that stuff come from ?