The correct temperature for the thermostat is 180 degrees.
Is your heater not as hot as it used to be?
Mine seemed only slightly cooler, warm, but not HOT like it used to get, and I found that my thermostat was regulating the coolant temperature in the motor at about 165 degrees.
I determined this by connected my Scangauge to the OBDII port and using the gauge function.
If your heater is HOT, then I'll bet that your coolant is hot enough.
I did not find that this impacted my fuel economy, at least not significantly enough for me to notice.
IF you end up needing to replace the thermostat, I would use a Genuine TOYOTA part.
I have pictures posted starting with THIS picture that show the process on my 2003 1MZFE Sienna.
http://rides.webshots.com/photo/2346...11220610ioJwMv
In this first picture, you will see that I bought 2 "O" ring type gaskets, 1 is the thermostat gasket, the other is the pipe to thermostat housing gasket.
The front oxygen sensor has its wires zip tied to the radiator hose that goes to the thermostat.
Remove the zip tie BEFORE you pull the radiator hose off of the pipe.
I did not, and the gentle tug on the wires that resulted cause me to have to replace the oxygen sensor due to a open heater element in it......and they are expensive.
The correct coolant for your 2000 Sienna is TOYOTA RED, not the pink.
The RED coolant comes as a concentrate, you mix it 50/50 with distilled water.
You can get it at your local TOYOTA dealership for just over $20 for a gallon, which will be plenty of coolant to do a drain & fill.
I got my parts online from toyotapartszone.
While the website is not super easy to navigate, it has by FAR the BEST parts break down diagrams that I have found anyplace.
My alldata and TOYOTA factory repair manuals don't come close.
Linear Mode
