Fuel Additive before or after an oil change?

[21Rouge]

I read that fuel system treatment is often done at the time of an oil change. I assumed this was just a way to keep track of the application of the fuel additive.
Is there any reason(s), in terms of efficacy, to put in the additive before or after an oil change or does it matter?

 

[caprice_2nv]

Usually people do it right before an oil change. The theory being that if any of it gets into the oil through fuel dilution or whatever that the oil change cleans it out to prevent any extra wear from the contamination. That's how I've always understood it anyways.

 

[FlyNavyP3]

I use the oil change as only a timeline for my fuel treatment. But I add mine after I've completed the oil change not before.

 

[Rolla07]

2 tanks prior is what i do if i even bother at all

 

[StevieC]

Originally Posted by Pablo
Not if you used the normal dose. If you used the double dose, for sure!

https://www.bobistheoilguy.com/foru...ng-oil-after-using-amsoil-pi#Post1171577

Just as an example. High dose PEA fuel additive.

 

[Onetor]

Originally Posted by Rolla07
2 tanks prior is what i do if i even bother at all


^^^^

 

[lzhome]

I don't think it matters unless you are adding a maximum or extreme dosage. There probably should be a warning on the product label if an oil change is necessary after following the prescribed instructions. Some diesel owners such as myself use an additive at every fill up so I guess it also depends on the specific additive.

 

[Greggy_D]

Doesn't matter.

 

[21Rouge]

Originally Posted by Greggy_D
Doesn't matter.


What if one has intentions of doing a UOA?

 

[demarpaint]

I usually do it before an oil change. In an EFI engine that is well maintained and runs well I doubt it matters much. If I plan on doing a UOA I'll add it a couple of tankfuls before the oil change, or maybe right after an oil change.

 

[ag_ghost]

Touched in this thread posted by Molakule in 2014:
White Paper - P.E.A. and Aminic Fuel Additives

 

[caprice_2nv]

The last time I used an extreme dose of seafoam to clear up a carb issue I was having I didn't bother to change the oil after but I also don't do the typical bitog long OCI. I was going maybe 4k with mostly highway miles and now it's almost completely city driving and short trips so it's going to be 3k max. This is on a 1976 Oldsmobile 350 with a quadrajet carb.

 

[DGXR]

I would prefer to do it just before an oil change, for the same reasons... some of the stuff that gets cleaned out will end up suspended in the oil and I'd like to drain it out sooner. It just makes no sense dumping extra contaminants into fresh oil.

 

[Kjmack]

BEFOREHAND

 

[ARB1977]

The Tacoma gets a dose at 5K intervals. So a double dose every oci.

 

[claluja]

Originally Posted by 21Rouge
I read that fuel system treatment is often done at the time of an oil change. I assumed this was just a way to keep track of the application of the fuel additive.
Is there any reason(s), in terms of efficacy, to put in the additive before or after an oil change or does it matter?


What type of additive? Cetane boost? Light decarb? Heavy dose decarb? Think it matters.