40th GT could be onto something. I just wrapped up a rebuild of an 05 that catastrophically failed all bc of a thermostat housing leak. Essentially, the coolant ran dry. After heavy overheating, and subsequent head warpage, coolant was added back into the system, which leaked into the cylinders which caused aluminum to be eroded (through some metallurgical process way over my head between coolant, fire and aluminum) from the head and deposited on top of the pistons in neat little piles. Aside from the combustion chambers being eaten alive, the heads were warped out several thousandths so the heads were little more than doorstops and had to be replaced entirely.
Hopefully you're case is [much] less severe.