Safe to mix Synthetic/Conventional Oil?

[bigsplash]

Is it safe to mix synthetic oil with conventional.

I have accumulated some oil that I got on sale, and would like to mix 4 quarts of Pennzoil Platinum 5W-20 with one quart of 5W-30 High Mileage oil.

Is this safe to do?

I have read on the internet that mixing synthetic with conventional can cause foaming and degrade the oil.

http://wiki.answers.com/Q/Is_it_harmful_to_mix_regular_motor_oil_with_synthetic

 

[Lethal1ty17]

its fine, there is nothing dangerous about it, nothing will be harmed. you mix oils when you top it off or drain it and refill because some is always left in there.

 

[Quest]

Never trust anything posted on wiki or wikileaks, wikianswers, etc. for they are typically contributed by authors who knew too little about the real truth but mostly anecdotal stuff/unsubstantiated krrap.

Q.

*and yes, conventional motor oil can be mixed safely with real synthetic motor oil*

 

[Steve S]

They [syn and dino] are compatible. Ever see the syn blend oil in the stores?

 

[chubbs1]

The mix of oils you are talking about is perfectly fine. The only ones you don't want to mix are the extended drain oils M1 EP, Amsoil SSO etc...with other oils because it could reduce the levels of base stock and additives warrantied under the extended drain. If you had a couple qts. of m1EP you could mix it with PYB if you wanted to, you just wouldn't get the full benefit of the extended drain of course. you are supposed to be able to mix all API certified oils and the nons like Redline and Amsoil can mix too. So just about everything

 

[dgee]

if they are both API certified, they can be mixed without any problem

 

[UncleS2]

Mix away & don't worry.

 

[electrolover]

i would not intentionally mix syn and dino. but to each his own