toy4two

I have been running Mobil 1 0W-30 for the last 2 oil changes. I get lousy gas milage (16 MPG).

When I first got the car from the dealership I was getting (20MPG) at 40k miles.

I don't know what kind of oil they used, but I would like to get that again now.

Should I be running Mobil 1 10W-30 for Southern California. The car only sees the snow twice a year for our Big Bear and Lake Tahoe trips.

Lexmex

You should be running a 5W-30 in a Mobil 1, 0W 30 is way to fluid for an RX.

HarrierAWD

Extra virgin olive oil seems to be the mainstay of Californian cooking.

Your dealer most likely used dino 5W-30. The correct oil for your engine.

salimshah

Look for other things (other than the oil) for drop in MPG. Any oil (which meets the specs as listed in owner manual) should be fine as long as it is replaced regularly on or before reccomeded intervals (time and milage).

Salim

flipside909

10w30 is perfect for SoCal climate. 5w is a little lighter weight...preferable if you live in the mountains where it's much cooler.

Most Lexus & Toyota dealers here in SoCal will use 10w30 for the 1MZ-FE and 3MZ-FE powered vehicles. I use 10w30 on my previous 1MZ-FE powered vehicles (Avalon, Solara) and 04 RX330.

vuvision

You'll be fine running 10w-30 for the toasty summer months, then switch over to 5w-30 weight for the cooler months.