Lower Temp Sensor
AudiWorld Senior Member
Joined: Nov 2009
Posts: 1,504
Likes: 3
From: Montreal, Que. (Canada)
There is one sensor in the coolant flange on the back of the block ("green" top sensor) as well as one near the bottom of the radiator. They provide the temp to the ECU that provides the signal to open the thermostat. If your thermostat never opens, the water around the block never gets to the radiator thus no circulation and the car will simply overheat.
AudiWorld Super User
Joined: May 2002
Posts: 5,138
Likes: 4
From: Redmond WA
There is one sensor in the coolant flange on the back of the block ("green" top sensor) as well as one near the bottom of the radiator. They provide the temp to the ECU that provides the signal to open the thermostat. If your thermostat never opens, the water around the block never gets to the radiator thus no circulation and the car will simply overheat.
The one in the lower radiator is not a sensor at all, but a thermo-switch to control the two speed electric fan.
AudiWorld Senior Member
Joined: Nov 2009
Posts: 1,504
Likes: 3
From: Montreal, Que. (Canada)
. Nothing worse than providing bad info 
. Next time. I'll make sure to find more than one source to be sure what I give out is right.Have a good one.
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