Something is wrong here.
This engine runs unusually clean and produces almost no "blowby" gases that produce sludge.
This engine was introduced in 2004 in the 2005 Avalon and is running in well over 2.5 million vehicles Toyota & Lexus vehicles.
There has not been one single case of engine sludge reported where the owner could produce receipts for oil changes.
What you call "routine" oil changes could mean every 12K miles.
Did you follow the 5,000 mile oil change interval recommended by Toyota and can you prove it with receipts?
I have this engine in my 09 Camry with 48K miles and when I change the oil at 5,000 miles the oil looks almost as clean as when it was fresh.
The only only significant problems this engine has had over the years is the oil line recalls issued in 2009 & 2010 and the "ticking" noise for which Toyota issued a service bulletin.
The only times I have seen this sludge issue come up
on this engine (interesting both on a Highlander) are:
My 2008 Highlander Hybrid is in the shop right now for this same issue.
I went thru the oil consumption checks, had an excellent record on file with oil and maintenance at 5,000 miles.
The entire engine needs to be replaced.
Extended warranty is covering a used
engine replacement, but not sure if I am going to go with this yet.
I may want a new engine put in.
They found sledge around the valves, all of them, and it seized up before I could complete the last oil consumption check.
By the way there is no oil leaks associated with this problem
Oops, sorry ... forgot to add:
Are you sure it was sludge and not a failed oil line.
If your oil line failed causing engine failure ..... Toyota has issued a LSC 90K "recall" where they will fix this ........ including a complete engine rebuild if necessary ...... through March 2013 with unlimited mileage.
Toyota will reimburse for the failed oil line and acilllary repairs even if you had it repaired elsewhere.
The recall affectied 1.6 million vehicles including the 2008 Highlander
Do a google search for "toyotaV6oillinescandal"
OR just go here: