Thermostat housing and coolant crossover, V6

The V6 thermostat lives in a plastic housing that goes brown and splits at the seam. The first sign is a sweet smell and a crust of pink on the valley, not a high gauge. The crossover pipe next to it fails the same way. Renew both.

Use the later housing number. Bleed at the throttle-body nipple with the heater on full until the pipe is hot both sides. An air-locked V6 will idle high and throw a random lean code.