LaguitasA4

I recently purchased an 06 A4 for my daughter. It was relatively well maintained for its one owner, 170,000 mile tenure.

The other day my daughter called to tell me it over heated. Needle went into the red and the display screamed "COOLANT".

She and a friend bought some antifreeze and topped it up so she could get home. When she got home I observed steam coming from the rear of the head and was able to take pics of where the leaking coolant had sprayed and dried.

Below are a few pix of what I was able to find but I'm not 100% sure where it's coming from and not sure how to fix it.

All of this is below the valve marked Hitachi

Any and all help is appreciated.

Thanks

Eric

LaguitasA4

John535is

Which engine?
There is a coolant flange at the back of the head on the 2.0 that is a common issue.
Also hoses for the heater and cooling hoses, all can split etc.

Its really a case of try and clean all the mess up as best you can, dry it off with a cloth, run the engine and use a good flashlight to look for the leak.

Once you fix the leak, what coolant did they put into it? there is a history of audi/vw coolant not mixing well with other types. Hopefully they used the recommended, otherwise you will need to flush the system with a chemical flush and start with new coolant. When you bleed the air, there is a bleed hole in the heater return pipe at the back of the engine, you undo the clamp, slide the hose forward, you will see a little white ring printed on the hose, that's the bleed hole. You need to expose the hole, when the thermostat open and the heater is on full, the warm water flows through the heater and you will see it bubble out the hole, then a steady stream. After that, use the bleed screw at the top of the engine to get the rest of the air back out, top up the reservoir and you should be good.

LaguitasA4

I replaced the flange, flushed the cooling system and put in the pink stuff.

The car runs like a top.

Thanks

Eric

ChrisRL

Eric and all, many thanks for this thread!
Well I had the same symptoms and got me a replacement coolant flange - only to find that I might have another problem, but it's very hard to see what's what... : )

a) removal of the existing flange (bottom hose still attached) was simple. I disconnected the ignition loom to get it out of the way, plus unlatched the permanent cable-tie that was holding the loom to the firewall.

b) the four bolts (two to engine, two to black pipe flange) all came out easily enough.

c) I pulled the entire coolant flange up to get to the clip for the bottom hose, and in so doing discovered a couple of things:

1) the coolant flange itself seems to be in okay condition. It's the older type with the two ports on top and a blind plug in one of the holes. My replacement only has the thermo hole.

2) the bottom hose connector isn't at all like the ones in any of the DIY threads. Looks like a plastic mount to the hose (?) and it looks like that plastic mount has cracked, which means that it's probably the hose and not the flange that is broken.

Questions:

i) How does one disconnect this hose connection? I'm reluctant to go at it with a pick, because the connector is plastic rather than rubber...

ii) What's the replacement part number for this hose? It looks like it connects the bottom outlet of the coolant flange to the heater core (?)

iii) hard to replace this hose?


Thanks all and sorry for the hijack! I figured this or a similar thread would be a good place to put my questions, though, since others following along this route might well run into the same problems!

Best
Chris

John535is

Chris - which engine and year?