Quick explanation about my rear coolant flange leak

[mdk]

Hey guys, just wanted to post this bit of information in case it happens to be applicable to someone else.

I started seeing a puddle of coolant under my car and noticing my coolant level dropping over the last weeks. Found that the transmission and back of the motor was very wet... figured the coolant flange was at fault. I was disappointed, however, because I had a shop replace it just a couple years ago (3 years ago, I suppose, though I read that they sometimes don't last long).

I began digging into it and found my flange to be intact - the plastic clip holding the temp sensor was the culprit. It didn't completely break (as I have seen mentioned elsewhere here), but it had become extremely flexible, and was no longer holding the sensor firmly in place. I found that it was possible to move the sensor around, while clipped in place, and I could here air/coolant bubbles leaking around the sensor when I moved it. Here's a picture comparing the one on the RCF to the one I took off the sensor on the radiator:



And here's a picture of the RCF, because I've found that every picture of that area helps when preparing to work on it:



So, I swapped the two clips (because the lower one is easier to get to) and flipped the bent one so that it kinda worked in my favor (sketcy) while driving to get new clips. The clips are part # 032121142 - local auto parts store actually had them as part of another flange, but it was cheap enough that I went for it. (No other local option within 2-3 hours).

No more leak! I suppose I got off easy this time, but hopefully this will help someone.

[Pdxtown]

I'm pretty sure my coolant flange is leaking but I can't see what part is actually leaking. I was pulling some wiring harness out of the way at the top rear of my engine and the sensor just came off the flange. I assume it's not supposed to do this? Do those clips hold it place. Or what do they actually do? It's so hard to know what's actually going on back there without seeing it.

[B6_A4_Kid]

That U shaped clip is what holds the censor in, I recently replaced the flange for my brother on his b6

[Pdxtown]

Oh so I suppose mine is gone because today I was messing with it and the sensor just poped right out. I'll have to look at it more tomorrow. Hopefully I can figure it out. I found a pretty good DIY if I want to replace the whole flange but I'm in exactly sure if the flange is bad since I can't see the leak....

[B6_A4_Kid]

Yeah. They just start to disintegrate after awhile, that would explain why you could just pull the censor out. I'm dreading the day when I have to do it to my personal b6. It is a pita to do because there is so little space to do it behind the motor.

[Pdxtown]

Yeah I could hardly get my hand back there. Looks like that's what I'll be doing tomorrow. I hate having to keep putting coolant in every week.

[B6_A4_Kid]

Yeah. I hear that, let me know if you need any web assistance, also my recommendation is to take off the lower skid plate before you start, once you start the project you won't be able to get that off. And if you do drop stuff on it your sol