Toyota ever fix the 1MZ oil problem?

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Did Toyota ever fix the 1MZFE "oil gel" (sludge) problem?

Ex, did the 2002-04 continue to be susceptible to sludge?

I've never owned one.

From a sample of one friend's 04 Sienna, I see the 3MZ does not have that problem.

But did the 1MZ ever get fixed, or did Toyota produce it for eight years with that flaw?
 
Looks like Toyota made the 1MZ for ten years.

Surely they fixed the "oil gel" issue at some point.

BITOGers who know Toyota well, do you know? I don't want to call you out.
wink.gif
 
Based upon the actions of the company in offering extra wty and repairs, I'm virtually certain that the remedial actions went into production with the 2002 MY engines. I've heard a couple variations of the explanation, but as best I can tell, they revised some oil passages in the engine, and probably improved the PCV system too. I would also imagine (no proof of this) that they revised the ECU programming with the idea of bringing operating temps down somewhat. I notice with some irony that it's rare for me to be able to coax my Camry hybrid's coolant temps above 200F (as reported via my SG-II). This is notably cooler than many domestic engines, which I understand run between 220 and 230F. When cruising here in the Florida summer, I see 185-195F. Might mean nothing, but who knows...

EDIT: the afflicted I-4 engine, the 5S-FE got no improvements. It went away with the intro of the 2AZ -- in 2002.
 
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ekpolk, you're the best.

Thank you for the details.

I realize the 2.2L 5S-FE went away. Besides being harsh on oil, it was too weak for the next generation Camry.
 
Originally Posted By: ekpolk
....they revised some oil passages in the engine, and probably improved the PCV system too.


Thanks for the interesting info. Question, though: Was it the oil passages or the coolant passages that were revised in the fixed engines? I thought it was the coolant passages since it's believed that Toyota made the coolant passages in the bad engines too small when Toyota was trying to improve their CAFE numbers.
 
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They may have improved the 1MZ-FE, but even the later 1MZ-FE engines are very hard on oil.
 
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