What is this?

[mrnickleye]

Originally Posted by Pretaco

16921 maybe?

Its for the heater hose to bypass the thermostat, otherwise the cooler water from the heater might close the thermostat and cause the engine to overheat when the heater is on. Older 22r engines had that problem until a new thermostat was designed for them.

Ray.

This statement is silly. Incorrect.

The by-pass system is there to allow the coolant to flow throughout the engine during warm up so that the engine warms up evenly, and does not develope 'hot spots'.

In fact, the thermostat won't even open if hot coolant isn't passed by it.

22r....that's balony info too. (that must be hearsay stuff) I am an ASE and Toyota Master Tech, and was the lead tech at the dealership from 1981-1985.