 My Sienna developed engine sludge at 
80,000 miles and is now at the dealer 
getting repaired.  Unfortunately, they 
aren't replacing the engine so who 
knows how soon the problem may return.
 Along with the squealing brakes when 
you come to a stop, now I have smoke 
bellowing from my exhaust when I start 
the engine cold.  
 I'm very disappointed with the way 
Toyota has handled this - first 
misdiagnosing the problem then trying 
to blame me.
 Fortunately I have my receipts showing 
changes every 4500-5500 miles so they 
couldn't get away with that on me.  But 
it didn't stop them from trying.  It is 
enough to make me take my business to 
Honda or Nissan. 