 Our Sienna also developed 'engine oil 
gel'. Guess that's PC for Sludge. We 
call it the sludgemobile too. Dealer 
just rebuilt the engine < 28k miles. 
Didn't fight either. We have 2 friends 
that have had rebuilds too.  One got 
back 4000$ on repairs. The brakes 
squeal, the AC broke < 12 miles, O2 
sensor broke, seat back fell off, 
visor broke (used about 5 times). 