Mixing Synthetic and non-Synthetic oil together

[zanzabar]

Originally Posted By: electrolover
i think pyb will mix with anything


Why?

I've been mixing oils lately in my 1qt/1000mile Volvo oil burner. Original fill of 4qts Rotella T6 + 1qt Rotella 15/40 dino. 1000miles later 1qt topup with Valvoline HM synth blend 10-40. 1000miles later changed filter and topup with 1qt Valvoline HM again. 1000miles later topup with 1qt PYB 10-40. At 6k total I plan to do a full change and I'll probably send in a sample for analysis out of curiosity.

 

[glum]

My goodness, why do people still parrot this age-old warning? The OP got some bad advice. It's fine to mix conventional and synthetic. The oil makers would be in deep doo-doo if modern oils weren't compatible.

 

[CharBaby]

Originally Posted By: Char Baby
I do it all the time. I buy so much oil on sale with rebates or closeouts. Some are fully synthetic and others are conventional. I usually use 3qts syn & 2 qts conv.


I have since cut back to 2qt syn and 3qts dino. I usually mix syn/dino based on how many of each I have in my stash to create a balance and evenlty use up my current stash.

 

[Sonic]

Back in the 90's I always mixed full syn with dino. I had a Chevy truck, I'd do 2 quarts full syn at every oil change and the rest dino. I'd run it 4000 miles. Not one problem ever. Sold it with 181,000 miles on it and it ran strong. I finally realized it wasn't all that much more expensive to just run all synthetic especially with the 5 quart jugs available. But if you want, mix away.

 

[oldmaninsc]

Originally Posted By: glum
My goodness, why do people still parrot this age-old warning? The OP got some bad advice. It's fine to mix conventional and synthetic. The oil makers would be in deep doo-doo if modern oils weren't compatible.

Exactly.
http://www.valvoline.com/car-care/motor-oil-myths/

 

[scion_xb]

I mix Valvoline as follows: 4.25 qts conventional with 0.75 qts Maxlife synthetic. This gives roughly a DuraBlend percentage with a little Maxlife. I use this in a 2002 Toyota (170000 miles) with the 3.0 Liter engine...running a 5500 mi OCI and probably going to increase to 6000 mi since the oil looks still new.
I use a 3.5 conventional with 0.5 maxlife syntheic in 2005 Scion (1.5 engine)with 70000 miles similarly.
These Toyota engines seem to love this combination.

 

[Alamogunr]

I wouldn't even consider this a mix, but I use Schaeffer's 9000 in my '06 Avalon that takes 6.5 qts. Since I have to have it shipped to me 2 cases at a time, I'm not about to break a quart just to get the half quart, so I use whatever dino I can find on short notice for the half quart. I've been doing 10K OCI's but this time I'm going to try for 12K and do a UOA to see how it does.
John
W.TN

 

[kcfx4]

i do all the time in my f150, 4qts M1 5w20 and 2 qts mobil clean 5w20, heck i call it mobil clean 8500 lol

 

[teddyboy]

Originally Posted By: chet2
some people say the additives arent compatible...i try to stay with same oil in car...or at least same visc


I understand wanting to add eye of newt into your crankcase, but frog liver? Does frog liver help prevent oxidization?