over heating !?!

[m19lte]

Help needed please,
I was tootling about today in the s3 and the coolant temp warning sounded, I immediately pulled over a turned the engine off. The temp gauge reached around 110° and the fans didn't kick in ! (They have always worked fine, even until recently)
The expansion bottle was boiling over and steaming out. Heaters work fine and can't find any cold spot's on rad/pipework, plus its returning back into the ex bottle. Head gasket water pump were done 12month back, coolant temp sensor done 6month back and thermostat done 2month back. All work done by a well trusted vag specialist.
I've let the car cool down and topped it back up but it keeps boiling over !?! Any help would be appreciated, thanks in advance

 

[<tuffty/>]

Check the fuse on top of the battery... the fans should work on low speed with the aircon switched on... normally they don't come on until 96/97 degrees... high speed comes on over 105 degrees or so IIRC...

If the fans aren't working when aircon is on then there is an issue with the fans... if fans come on then it could be a water pump failure... when was the cambelt last done and was the pump done at the same time?

<tuffty/>

 

[m19lte]

Checked the fuses and they all. Look good, with no corrosion.
I'll try the air con now tuffty. Belt/pump was all done about 12month/3k ago when I got the rod's done,

 

[m19lte]

Heaters blow hot, and it's returning back into the ex bottle so wouldn't this rule out pump ?

 

[<tuffty/>]

Not neccesarly... if youare saying the fans weren't on when it went too 100 plus degress then tbh it sounds like an issue there... ideally need to track temps in VCDS as the dash gauge doesn't move over 90 deg until its hitting well over 100 actual degrees... this is to prevent owners from worrying when the temps get to nearly 100 degrees under normal use...

<tuffty/>

 

[m19lte]

Thanks again tufty, I'd just had a fiddle round with it (didn't notice anything wrong) messed around with the connectors and put a aircon on and everything seems fine now, fans workin and no boiling over. Do u think it's likely a dodgy connection ?? The pump was replaced about 12month and 3k miles ago with when i bought a full dm forge rod kit from ina eng issam, it came with a 'geba'metal impeller pump, is it likely to be this ?? Temp on torque obd was in the 70's (72 I think)

 

[<tuffty/>]

The requirement for metal impeller pumps is a myth tbh... all the ones I have seen leak through the shaft after a while..

The fuses on the battery corrode... this happened to mine...

Replaced the fuse and cleaned up the fuse holder and things have been fine so far but its a really common problem

<tuffty/>

 

[m19lte]

Yea I understand the pump myth (that's why I asked) it's just that it came in the full head off kit with the rod's. Checked the fuses and they 'look' fine with no corrosion what so ever, they are seated nice an making good contact with the connector. They are well protected with contact lube. Looking at that pic though and someone has just mentioned to me that possibly that the connector itself can melt underneath ! I'll try that 2mrw, failing that im thinking maybe fan switch or modulator !?!
Thank vmuch for your help tufty