Originally Posted by masboy

My car 2006 gs430 with 170k miles. Been using all over synthetics oil brands from mobil1 to Walmart brand, not a single oil leaking problem so far. Oil change every 5k.

The main issue is 2006 gs300 mostly. Sorry to say this but you shouldn't get that car from first place. Seems like nothing but problem with most 06 gs300 owners.

Originally Posted by LOLjasonW

everywhere ive read this is normal for these years and models, especially with higher mileage motors. Most have said rebuild will be in your future. Im not 100% on what causes this, but i believe head gaskets are the concern

Originally Posted by MX73

You would have a lot more issue if it was a head gasket. You would also see signs of coolant loss, oil mixing with coolant, coolant burning through the exhaust, reduce engine performance, engine shaking, etc.