Originally Posted by
gtmike
it's in the avalon,IS,GS,ES,RX,camry,and rav-4.....about the whole sludge issue...it's not just the 2MZ-FE that toyota has problems with sludge....but my theory is there operating temerature of there motors...aluminium expands more then steel soo...the aluminium block expands larger than the bore was origanally designed for and thats where you get the sludge and oil consumption...just what i think though....
the cylinder liners are still (at least) steel, often times with composites added to tighten ring seal even further. This is the case with many modern alum engines.
I'm not really sure what causes sludge to form, other than not changing your oil often enough.