You have a 2.7T? What year?

I looked for it in my manual and it doesn't show a line off the bottom, not that the manual is correct. I wonder if your expansion tank is broken and not holding pressure and blowing out the over flow or they may have put the wrong tank in as a replacement, should have 2 hoses to front, feed and return and one to the rear pipe, but it shows that one is teed off the other line not from the tank.

 

Well, you have to have an overflow. The cap needs to vent pressure and fluid somewhere or you'll be cracking tanks and bursting hoses...

Not that this is one, but its there somewhere. From all the tanks I have seen, there is one at the top coming from the upper radiator hose, one at the bottom heading back towards the thermostat housing or somewhere else low in the system, and an overflow. Thats 3 hoses. Fill the tank up again and see if the hole the original lower hose was connected to drains the fluid too, if not then the hoses were connected wrong.

 

I have the bentely manuel, and your right, the hose on my expansion tank has a hose in the bottom, but the manuel does not show this.

I have a 2001 a6 2.7t.

If this hose is the over flow hose, why would the previous owner have capped the line? Wouldnt my tank have cracked by now (15K miles later) if the overflow line was capped for all this time?

 

No the system is always under pressure the overflow must open under extreme pressure. yours may be broken so they would have to plug it or you wouldn't cool properly or the tank did brake and this is a replacement from another model or worse a chevy vega. NEED PHOTOS

 

The hose you are talking about is the overflow/pressure relief hose. It does look like it has been cut, but it is actually a factory cut. The correct location is not so important, but in my case it is hanging down towards the back of the engine.

 

Loach1,

What would be the previous owners reason for capping it then? Or is it not capped?

Pictures attached:

 

can anyone provide some information on this issue?

I really want/need to find out where that hose goes.

 

It looks pretty normal to me. We are talking about the same thing - the hose directly under the filler cap? There is a white cloth disc and a 90 deg elbow then the rubber hose, which looks like it has been slashed by a machete, right?

With the cap off you should be able to blow through it, but with the cap sealed you should not be able to blow through it.

This is the pressure overflow hose. If the pressure reaches a dangerous level, the cap will bleed off pressure down to this tube.

 

thank you!!!!

your description is perfect! EXACTLY what i have on my car. THANK YOU!!!!!

 

So.. after all that...