1999 Toyota Sienna LE thermostat location?

[ricecooker]

I have a 1999 Toyota Sienna LE (6 cyl)

Where is the thermostat located? How hard is it to get to (how may bolts to remove, etc)? Should I change the thermo with the hoses and new coolant? Do you really need a Genuine Toyota thermostat or will the friendly auto parts version due?

[jc]

Ricecooker,

Here is a link to the components for the thermostat
http://minivanclub.org.ua/info/Sienn.../ther/comp.pdf

Here is the link for the removal of the thermostat.
http://minivanclub.org.ua/info/Sienn.../ther/remo.pdf

The link to the whole user manual is right here
http://minivanclub.org.ua/info/Sienn.../ther/remo.pdf.

Are you sure you need to replace the thermostat? What are your issues? Over heating?

Regards, Jason.

[irlandes]

Buy a Toyota thermostat, and replace them at around 100,000 miles or 5 years. Brand X may or may not be as durable, and there is such a thing as false economy. Some say the Toyota thermostats never need replaced, but I talked to an engine rebuilder who says he sometimes gets Toyota heads to rebuild or replace, somewhere around 150,000 miles, because of bad thermostats.

For a number of reasons, it is not always a good idea to wait until a part fails to replace it, and a thermostat is the best example I can think of, because you just blew $2,000 in repairs when that sucker breaks.

Keep good coolant in the cooling system. It won't break you.

[wiswind]

Here is a link to the first in a series of pictures of the thermostat replacement job on my 2003 which should be almost identical to what you need to do on your '99.
http://rides.webshots.com/photo/2346...11220610ioJwMv

The "O" rings are for the tube that you need to remove and the thermostat gasket.

Your 1999 Sienna came from the factory with Toyota RED coolant, not pink.
I would recommend sticking with the red coolant.
I would also undo the Zip tie that holds the front Air / Fuel (Oxygen) sensor to the radiator hose before pulling the hose off.