I don't know if y'all are as neurotic as me, but as a fellow "while you're in there" type of home mechanic I pulled the heads on my 2011 Sequoia so you don't have to. This vehicle has 220,000 miles and i just picked it up about 2 months ago. Unknown history. This is a vehicle I bought for a family member and want it to last another 10 years at least. It started with the valley plate reseal, then moved to pre-emptively fixing the timing tensioner issues these engines have. While I was in there I figured I'd reseal the cam towers. And while I was in there I figured I'd pull the heads for peace of mind, I mean I was 90% of the way there anyways right?
I can make a new thread on this for those interested but what I found was some delamination of the head gasket coating around the suspect coolant ports but not bad at all. This easily would have held up fine for a long while I suspect. Passenger side was better than drivers side. Both heads perfectly flat, drivers side block surface actually did have a low spot near the suspect coolant port, but a .0015 feeler gauge would not fit. I could barely see light under the straight edge.
If you keep up on your coolant service and avoid overheating I wouldn't worry about this at all personally. I suspect overheating would cause this issue more than anything else. This is personal opinion but based on my research I no longer run Toyota SLLC pink coolant. It uses sebacic acid to make it last as long as it does, but sebacic acid is a plasticizer and not necessarily the best thing for coatings, plastics and rubbers. I personally prefer to change my coolant more often and use something with a shorter lifespan but safer on plastics and seals.
Enjoy some photos
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