i have a slow coolant leak - its coming from the coolant flange on the rear of the head, where the temperature sensor is... its not the coolant flange housing. the hose on the underside of the housing looks like it clips in - it isnt a jubilee clip, looks like a plug in type - i think it possibly might be the heater matrix pipe. i expect as it plugs in, it will have an O-ring that has become worn over years of use, and caused the leak

does anybody know what size this o-ring is, the housing seem to be cheap enough so i will replace that too to eliminate any problem that it might be that, as its made from plastic it might well be warped

that o-ring though deffinately needs replacing - i just need a size or part number

 

Check this post I made last year:
https://www.audiforums.com/forum/b5-...9/#post1367283

 

thats the one cheers - mine is deffinately coming from that hose, i can see it dripping down on to the gearbox.

7/8" x 1 1/8" x 1/8" O-ring,
22.5mm o-ring

 

I just replaced the coolant flange on my 2000 1.8 atw. That o-ring was the only thing I DIDN'T replace, and I'm now dry as a bone.

Maybe you should change the flange while you are back there. That fitting is smaller version of the top and bottom radiator fitting, with the metal clamp that holds it on by locking into a notch.

I took that off first by driving it down with a screw driver and hammer, and it was the first thing I reattached when reassembling.

 

does that pipe just unclip? - i cant see properley on the car and my shovel like hands dontreach through hahaha

 

aah with the metal clip - yep gotcha, ill see to it when i get a new one. fingers crossed this is the last thing on my list of things to do.

 

what an **** of a job!! removed the hose, no o-ring in there, put one in, tried reconnecting it.... well it wasnt having that, lots and lots of swearing grazed knuckles and scratched forearms later i finally removed the housing ... who assembled these things? a group of leprachauns?? how do they expect normal sized people towork on these things, you expect it from the tiny japanese, not the germans though!!

so try again with the o-ring and it will not close, i look at this further to see that the inside of the pipe is rubber lined the same shape as the male connecting part and it fits snug and tight. the leak was small - im guessing this doesnt use an o-ring as it is very tight without one. i will need a new hose i think but for now i removed the hose and housing and put some instant gasket in and allowed it to dry before re-assembling. its waterproof and withstands high temps.

lots more swearing, knuckles dripping with blood and forearms with deep slashes in and its back together - no leaks - even my temp sensor is working now. which wasnt before

only a temp fix till i get a new hose

 

Sounds about right for that job. My cuts and scrapes are just about healed up from 4 weeks ago doing this job. I still believe that the gasket in that hose is very deeply seating in there and you may not have seen it. Anyway, great work and I hope you learned some new foul words that go naturally with an Audi. I'm back there again working on the Combi valve, which you don't have, so it could be worse. Cheers

 

I have also replaced that same exact hose in the past and yes it is a royal pain in the *** to do haha totally agree...I also pulled mine off to find an O ring that at one point in time looked repaired and had all kinds of black gunk glued to it like that was really going to help. Best bet from my experience is just figure out what hoses you have that are cracked or need replaced and do them all at once and wearing some type of mechanic gloves will help to as I scraped the hell out of hands.