Toyota Repair: 1999 Toyota Avalon sludge questions, sludge problem, toyota avalon

Question
Hello Ted,
I bought a 1999 Avalon new at in 1/99 from a local dealership here in San Jose, CA.  I understand that the 3.0L V6 installed in these cars has been know to have a problem with creating 'sludge' eventually leading to some serious problems.  I further understand that even Toyota has acknowledged this problem and has offered to extend the warranty on this problem.  I have been doing the oil changes on this car myself.  I have been changing the oil and filter approximately every 5k miles using MobileOne 10w30 and Toyota factory filters.  The car now has about 50K miles.  I have noticed some unusual deposits on the valve cover directly underneath the oil fill cap.  I would describe them it as a 'crunchy' black crust that can be indented with ones finger nail.  My questions are:

1) Is there a sludge problem with these motors?

2) If there is, is there a reasonable accurate way to determine the extent of the problem in my engine with out tearing it down?

3) What is the best way to successfully approach Toyota in getting a replacement engine?  (Assuming that is the fix)

4) What (if any) general recommendations do you have for this problem.

I am have two basic concerns.  It will be difficult for me to gather 'proof' of my own maintenance.  I naively assumed that frequent changes with top quality stuff was all the 'insurance' I would need.  Secondly, I suspect that I have inadvertently pushed the problem out to the extent that it will not become serious until after the 'secret' warranty has expired.  I really had assumed that this engine (and car) would easily go more then 200k miles with out the need of major engine work.  

Thanks in advance for your thoughts,

evan linick

Answer
Toyota has publicly accepted responsibility and has repaired or replaced engines as necessary if there is a valid problem.
There are certain criteria that have to be met in order for the factory to assist in this matter.
The way to go about this is to take the car to a Toyota dealer for inspection, they will remove one of the valve covers(this may be at your expense)if there is an oil gelling condition(Toyota's terminology)there is a step by step procedure to determine what course of action to take and whether or not the factory will get involved, I think they are dealing with this on a case by case basis.