A friend's 2004 Rav4 consumes 1/2 quart of M1 5W-30 over 4000 miles with just 20k on the odo. At 16k miles he switched the engine from dino to M1 5w30. Toyota recommends 5k oil changes with dino and suggests sticking to that even with synthetic oil. Is that normal oil consumption for a RAV 4, and what about choice? Any suggestions?