johnny quattro

Help! Anyone!
2004 A4 1.8T Quattro (AMB engine).
While topping up my coolant today (down from Max to Min in 3 months), I noticed a pink staining or residue at the rear of the engine casting, beneath the combi valve assembly.
No leaks underneath, no codes or CEL's, etc.
Can anyone confirm what this could be or what is causing the residue?
See the three pics below.
Thanks anyone!
Johnny Quattro

seanf

im gonna go with bad coolant flange on the back of the head, i have coolant crustys like that around the hose going to my oil cooler, its definatly coolant.

johnny quattro

Thx Seanf!
I think you are right.
From what I have read, inexpensive parts to replace, but according to audi write ups, I understand it is a B....... of a job to tackle.
Any suggestions or tips?

seanf

I can't give any tips cause I've never done one yet but I can say you might as well change the temp sensor and the rubber hose that come off the coolant flange and goes to the upper hard pipe

johnny quattro

I'll change them all.
Thanks for the advice!
There are 3 pretty good write ups on Audizine, so I think I will tackle it myself.
I'll keep you posted.

johnny quattro

Well, I chickened out! (Hate busted knuckles!)

I ordered the parts through Audi $110 incl Tx (Flange, O Ring, CTS, Clip, Combi valve adapter gasket & G12 coolant)

Had my local guy at Schmidt & Shaw do it. $220 (Incl Tx) for 2 hrs labor.

$330 total (incl tax).

We agreed it is easier to access the coolant flange with the combi valve and adapter removed (hence the gasket required).

In the pics below, you can see clearly that the flange and flange O ring is fine.

The leak appears to have come from the CTS (coolant temp sender) O ring. You can see the coolant stain above instead of below the O ring.

In hindsight, I could have simply popped the clip on the CTS, changed the O ring ($1.60), and reconnected.

Well at least it is done!