Need help with 2005 Toyota Sienna thermostat not opening

[Scottintexas]

We have a 2005 Toyota Sienna XLE, 192K miles.

Recently I noticed the coolant reservoir was empty and I refilled it. I day later half had disappeared. I looked closer and found my water inlet fitting had the clamp on to tight and it crushed the flange causing a leak.

#13 here
http://toyotapartsestore.com/2005-t...tic_trans_speeds-engine-engine_parts-8530040/



I ordered a new one and installed it today following these great instructions,
http://www.shareyourrepair.com/2014/12/how-to-replace-thermostat-on-2004-2006-toyota-sienna.html

Everything went great except when I disconnect the inlet wiring harness (step 8A in the link above)

Half of the clamp broke when I took it off. When I reinstalled it I just kind of shoved it on there not really understanding what it's function was but it definitely had a wire or something connected because it stayed around and didn't fall to the bottom.

I put everything back together, ran it around the block, it runs with no leaks but the engine became very hot, all the way to the red about the time I turned it off.

Both of the radiator hoses were cool to the touch leading me to believe the thermostat isn't opening.

Any idea what that wire harness does? I looked over the internet but couldn't find anything I thought the thermostat worked independently.

It will take me about an hour to disassemble everything to get a better look at it again.

 

[veedubtek]

It's likely just a temp sensor. Not causing your issue now.

Blind guess without seeing it - you have an air pocket in the cooling system. Google around to see if there are any tricks to "bleed" the coolant system on that particular model. I use a vacuum filler, makes life easy but likely not worth the cost if you aren't doing it every day. Before that, I used to pull a coolant sensor out on the back side of the head and fill until coolant started coming out that hole. Same basic principle you'll be doing - you just need to open something at the highest point while filling.

 

[Scottintexas]

Thanks @veedubtek
I bought this 35. Funnel with radiator adapter

Got a couple good burps and it took about 2 more qts of coolant and works great now

 

[veedubtek]

Glad to hear it!