Coolant sensor on the back of the water pump housing. I guess you have to remove the alternator to get to it, but is there anything else you have to remove to get access? Its a long sensor so I wasnt sure if you could remove it w/o taking off the intake?

One more-should you use teflon tape or pipe thread sealant?

 

It will screw out easily with the alternator removed. There was no sealant or thread tape on mine when I removed it, but I used some tape just to be on the safe side.

 

Thanks for the info. The sensor was so long so i wasn't sure about removal interference. There's a harness in the way but I think I can move this when I unplug a couple connectors. I'll go with teflon tape too. Thanks

 

What are the adverse effects of not running one? The connector on mine snapped off....

 

Very poor running when the engine's cold and less-than-optimal running when warm. You should definitely replace it.