One problem related to engine grinding noise has been reported for the 2007 Lexus RX350. The most recently reported issues are listed below.
I own a 2007 Lexus Rx350. When starting my car, a grinding sound is heard coming from the engine every 1 out of 7 or 8 times. The performed a diagnostic test, and the dealer advised that the camshaft tower would need replacing. Apparently this is a common problem with the year, make, and model. The failure mileage was 89,000. Lexus said they woulc cover parts but not labor, labor is 2/3 of the cost (total estimate $3800). Apparently the car is unsafe to drive as is.