My stock one had cracks so it was time to replace it. I've been through 2 new ones already because the coolant leaks out where the coolant level sensor connects. I got fed up and just filled it up with high temp. silicone and jumped a wire on the connector to fool the ecu to think that it's connected. I haven't tested it out yet, but hoping it wont leak anymore. The test is driving the car to work (50mi. away) subjecting the tank to being pressurized for a while, since that's when the leaking would happen before.

 

It most likely isn't leaking from the connector but from the nipple at the bottom it leaks once pressurized because your coolant cap its bad.

 

I thought it was that at first, and got a new cap but it was leaking still. After arriving at work, I removed the connector and all this coolant started dripping out. I guess I'll find out what happens on Mon.

 

Just came across this thread and am having the exact same problem with my '00 s4...I've put three new tanks on it and have had it leaking out of the coolant level sensor port on each one...did you end up figuring out the problem? All I can think is that there has either been a bad batch of tanks from the manufacturer or the plug for the sensor has to be fully locked in in order to keep the o rings on the sensor itself seated in the tank. I finally tried some two part epoxy on it but it didn't adhere to the plastic...any help would be great thanks.

 

The connector shouldn't have anything to do with keeping the coolant in the tank, that sensor is molded into the tank. Are you positive that's where the leak is coming from? Almost sounds like a defective tank...

 

double check the lines and cap... no need to drive ur car 50 miles just to see if the silicone works or not... u can do it at home just turn ur car on rev it up to like 2.5k rpm for a while until i warms up or just drive around the block a couple times then pop the hood while the car is still on and inspect to see where exactly its leaking from...

 

Ha, ha, I forgot about this thread once I fixed the problem. I ended up figuring out that where the two pins are, is actually molded to a separate plastic piece that's just held on by glue. On the inside it has tiny gaskets that are around each pin. taking all that out, there are two small holes which I just plugged up by inserting some tight fitting screws in both holes. It never leaked since. This is after trying a couple of different glues/epoxy/silicones which all failed.

 

Youre right about the pins...for future reference, the problem ended up being three faulty tanks in a row, presumably a manufacturer defect in the "gluing" of the coolant level sensor into the tank. I finally picked up a tank from a different supplier and it works perfectly. Thanks for the replies.

 

Just another Audi problem. Sell that piece of junk. Audis are just for looks. Go get a more reliable car like a Toyota.

 

a whopping 12 posts and nothing intelligent to say in any of them...