2008 LS460......valley plate leak

[Dugmahn]

Greetings from a new 2008 Lexus LS 460 owner. Huge thanks to this website for helping me get a couple of critical things fixed namely the control, arms and rearview mirror whistle on the passenger door side. My model has 65,000 miles, and the owner sold it because the stealership wanted excessive amounts to service the car. So they just gave up on it.

There are a couple of problems that I need to resolve in the near term and wondered if I could get some advice here. The dreaded valley plate appears to be leaking very slightly.  However, after watching all of the YouTube videos on the reseal job, it looks like it's a really involved and complicated process and I am wondering if anybody has tried any radiator stop leak on it? I know this is probably has some people cringing and wanting to throw me off the forum for such a suggestion, however, the thought of pulling the Plenum and the associated equipment off is really imposing. 

Secondly there is a minor problem with the radio/HVAC control system. Intermittently the radio controls will not work except for the controls on the steering column. In addition, the HVAC temp control always defaults to 75° degrees and does not hold its prior setting. Any members know if there is a reset available for the HVAC and radio? Thank you again to this group for all of the awesome information available for our cars.