Originally Posted By: jeeprnovru
and also why are some engines sludge monsters and others not?
what makes a sludge monster?
Good Question, what makes a sludge monster is when you extend your OCI's, highway driving, maybe you can extend your OCI's.
Short trip driving you cannot extend your OCI's, now there were certain engines that had very small oil return holes in the cylinder heads, the people that extended there OCI's did have problems, the ones that did not seemed to have less problems.
There were people who followed what was written in there owner's manual as far as OCI's and they still had sludge, maybe they did short trip driving, maybe there thermostat was stuck open, maybe there engine did not get up to temp to burn any junk off.
We do have a member that had a relative that had a known Toyota Sludger, she did get a notice from Toyota, her engine was spotless, she did do short trip driving, this member was wise enough to put in a certain oil additive that kept this engine spotless, this additive is called MMO.
If anyone has doubts, then I can go and look for his post.