Hi Im having trouble finding the ECT sensor on my Audi A4 Quattro 1.8t
The car would not start after a long ride but it does if its cooled down
took it to pep boys to get a code retrieval as the CEL was also ON and
after a a diagnosis they said the ECT sensor is faulty and i have a coolant
leak but the sensor might be causing that. they are charging me $250 to
replace a $20 sensor and was hoping i could just do it on my own but i cant locate it Here are some pictures.

Help Please

 

Check this image out:

http://forums.audiworld.com/picture....ctureid=161493

The upper ECT sensor is behind the engine close to the firewall and below your intake. It's kind of tough to work your hand back there but once you do it's pretty easy.

Your lower ECT sensor is found on the lower radiator coolant hose. Again, slightly tough to get to, but really not all that hard if you're somewhat experienced.

If you replace them, make sure you get the O-rings as well to replace your existing ones.

 

if you truly have a leak it is likely your coolant flange which holds the upper ECT. The coolant flange costs ~$35 and can be replaced by anyone with some decent experience. Not technically difficult, just a tight squeeze and a few layers of vacuum lines and breather tubes to peel off to get at the part. Image 3 is where the coolant flange and top ECS is located. The more stufff you take off the easier it is to get at since it is bolted to the back of the head at the top right against the firewall. Plenty of DIY writeups if you look.

If they charging you $250, go elsewhere.

If you want to change out the bottom ECS, plan on doing this during the timing belt service or thermostat change. You will loose a lot of coolant.

Good luck!