If the Cam Gears empty because the valves released all the oil, when you do a cold start the synthetic will flow back in faster. Probably more so in cold weather. It also lubricates better and can leave a thicker film on the internal parts.

 

The CAM gear rattles at cold startup every time for just a few seconds. Sounds just like the rattle on the 350. Is there reason to believe it will get worse and or damage something? Really trying to decide if I want to ditch this car.

 

Would adding something like Marvel Mystery Oil to the crankcase help some?

 

Update: In response to the engine rattle I have decided to switch to Castrol Edge full Synthetic Oil 5w20. I have yet to switch it out, but I want to see if this will get rid of my cold start Cam rattle. Stay tuned! I also purchased a few cans of Seafoam and performed an engine clean. I shot a video explaining what I did as I was not able to find one for the IS250 online anywhere. I bought 1 can with the nozzle attachment to spray through the brake booster vacuum line and I poured the other can in the fuel tank. I was not able to get it to smoke, which I assume means the engine is more clean than I thought.

 

The dealer says "just live with it", implying that it shouldn't get bad enough to damage anything. It just sounds like crap - Is this what Lexus has lowered itself to?