New here so sorry for any future dumbassery, not sure where to post and what not so please bear with me.

I bought an RX-8 a few months back and the previous owner runs synthetic so I'm going to change it to conventional. My question is how do you completely drain the oil? I heard it take about 4 liters to refill with a normal change but there is still oil left in a reservoir somewheres...so if I heard correctly how do I drain ALL the oil so its completely fresh?

Been looking around for quite sometime and can't find anything so your help is appreciated, thanks!

 

IIRC, generally people just double drain(forget the proper title). Do a change with as much as you can possibly drain, then fill it up with Synthetic, run it for a little while(to cycle the system and mix the oil inside the engine), and drain it once again.

Mixing the two won't hurt if that's what you're worried about in the first place. Mazda dealerships are actually switching to a semi-synthetic 5w-30 in the Carolinas as the default fill-up oil.

 

So I wouldn't have to completely drain it then even if the old is synthetic and the new is conventional?

 

They are compatible, just proceed with normal changes. No reason to go through a hassle.

 

well this is good news, thanks guys!