I bought my 2007 Tundra in…
I bought my 2007 Tundra in 2017 when it had 270,000 undocumented miles, I immediately put it on a 'server service' maintenance schedule but the damage had already been done... one or all three of the previous owners did not flush the coolant as often as they should have and the head gasket failed in cylinder #7 at 316,000 miles. Tear down inspection before making repairs revealed that they had also run the engine while it was low on oil, this resulted in scored cylinder walls. I replaced the original with a used low mileage engine, before installing it in the truck I went ahead and replaced the head gaskets, timing components, starter, alternator and cooling system. Over the next 15 years I will change the oil & filter every 5k or sooner, and I will flush the cooling system every 50k / 5 years or sooner. I will replace the transmission with a Toyota remanufactured transmission if / when it dies.