If one were going to start testing different brands of oil every oil change would enough oil be left in the motor to skew the results?

I'm trying to decide the best way to do this. I thought that when the oil is changed every 3K the best thing to do might be to drain the brand x oil, refill with brand Y, and drain and refill brand Y again in a few hundred miles to get out any left over oil?

I really hope this isn't needed!

I'm thinking just drain, change filter, and refill.

 

That would be overkill. Don't waste your $. Also, run the oil for 5K before you do the oil analysis. All of the major oils should still be useable at 3K so I don't think you would learn very much.

 

"I'm thinking just drain, change filter, and refill."

My 2 cents: that's what I'd do.
Brian A

 

Stab man you're startin' to remind me of myself - don't rack yer cranium on it - just go for it - do what's gonna keep the "AG..." factor to a minimum FOR YOU!

Ain't NOTHIN' "perfect" - anyway - least not in this life, in this world.

The ol' "TL" is gonna be standin' tall again (back on my feet) SOON - and I'll be doing some analysis - though maybe I'll do some similar to your's and some different ... for comparisons sake.

Glenn . . .

 

The scientific method would require the more expensive approach to eliminate residuals (test 2nd fill of same oil). There are so many variables that you have to control if you want to get to a more believable answer. Weather is a HUGE variable that many people overlook. They test one oil in the summer months, then the next one in the winter looks worse, even if it's a better oil. So make sure you are comparing oils during similar weather conditions.

An alternative would be to test each oil fill twice, once at 2000 to get a baseline, and the 2nd at 5000. Then compare the ppm/1000 mile results on the 2nd half of the fill (subtract ppm of first test) which should be a reflection of the oil/engine performance without the residual effects.

 

Now "Professor" rgiles - he's another animal all-together - (ALL in fun Mr. Giles!).