I got a new radiator for my car but the threaded port on the bottom left of the radiator is the wrong size for the sensor that came out of the old radiator. From what I can gather, this switch is part of the emissions system so I probably cant just trash it. Are there different size sensors for the S4 vs. S5? Maybe the S5 one will fit.



If I cant find another sensor that will fit, I'll probably just have to plug the hole and either leave the wires or jumper the wires so that the ECU thinks the radiator is always hot.

Bump



It looks like I'll have to chuck the sensor to get the rad in. What does this sensor control in the ECU? Am I going to blow something up by throwing it out?



Any help?



Thanks

Andy

it basically turns on the emissions and o2 feedback systems in the ecu. just wire it so its "on" all the time, if you care about mileage.

I thought I had done that.



Which way is 'on'? Open or closed?



I checked the sensor while it was cold and it was a closed circuit. I figured that when it was hot it would be the opposite, so I just left the wires open. However, my gas mileage seems to have plummeted. Maybe my sensor was busted and stuck on all the time? I guess I'll jumper the wires and see if it gets better.

i wanna say it closes when its hot, but thats just a guess.



if your mileage plummets, then thats the real clue

Yep, the sensor is supposed to close when hot. I guess the sensor was fried.