a_steffani

I just replaced the wire housing and my ect sensor and have everything set, the the Damn retaining clip doesn't feel like it has a good grip. It also leaks a little bit. Is it supposed to clip over the brass part of the sensor? Or above in the green plastic?

CRuby

IIRC, the clip goes thru a slot on the housing & staddles over the green plastic part, just above the brass. There is an O-ring that goes over the brass sensor end before you insert it into the coolant hole. Do you have the O ring installed? If not, the clip may not feel like it makes a tight fit & coolant will leak past the sensor. Some pics here:
Audi C5 A6 Quattro 2.7T Engine Cooling Temperature Sensor - ECS Tuning

a_steffani

The O ring is installed, but the sensor won't go down far enough for the clip to reach the green part

johnkk

Make sure the old o-ring is not still in the hole.

Airbag

Bingo !!!!!

he didnt take the old o ring out ..

a_steffani

The old I ring came out with the old sensor. The one that came with the new sensor was too thick so I replaced it with a thinner one.

CRuby

The O ring that comes with the sensor is the correct size O-ring. If you replaced O-ring with a thinner one, there is your problem. Thinner one would fit loose & leak.

SloopJohnB@mac.com

Lubricate it with coolant before you install the sensor. You can even use raw coolant rather than 50/50 mix.