2.5 TDI Air Lock in coolants ?

[Turkster]

I'm about to look at my coolant condition and most prob change it, cant say its been down in the last 2 years, 2.5 TDI AKE,

Can you get air locks in these engines and how do you get rid of one should you get one ?

 

[S4_dan]

These are self bleeding systems. Just leave the cap off with the engine idling and get it up to temperature. Check level, top up if required with warm water, then fit cap.

 

[AlexGSi2000]

If you remove the big plastic scuttle panel cover by the wipers - you will see the coolant hoses going to the heater matrix.

There is a small hole on one of these pipes - before filling, move the clip so the pipe is free and pull off the heater matrix hard pipe most of the way - this small hole is the highest part of the cooling system, so as you fill, air will escape from the top.

After filling coolant to the full mark on the header tank - start the car turn the heaters to full temperature and fan speed on medium - keep an eye on the coolant bleed point on the heater matrix pipe - as soon as coolant starts trickling out - push the pipe back on and re-seat the clip - make sure the header tank is topped off - job done.

 

[Mike_B]

Not sure if the V6 is the same, but on the 2.0 FSI there is a water pipe running over the top of the engine, which has a hex headed bleed screw in it. The recommendation in Haynes is to remove the header tank (only one screw, so easy) and lift the tank a little to give a gravity feed into the system. That said, when I changed the tank recently, the system bled through without doing that.

 

[S4_dan]

There is a small hole on one of these pipes - before filling, move the clip so the pipe is free and pull off the heater matrix hard pipe most of the way - this small hole is the highest part of the cooling system, so as you fill, air will escape from the top.
.

No hole on my 2.5 AKE. I had the pipes off mine couple of weeks back to carry out a back flush and niether metal pipe had the hole you mention?

 

[Mike_B]

It'll be in the rubber pipe if its the same as the 2.0 - top one - very small - the idea is that you pull the pipe back such that the hole is clear of the metal one, but the pipe is still on the end of the metal pipe. We did this on mine - having remembered to put the heater on to hot - and it certainly did the bubbling thing as expected. Then we cracked open the bleed screw on the pipe I mentioned, the one running across the top of the engine. More bubbling.

 

[S4_dan]

No bleed screw on rubber pipes either. I looked everywhere. It bleed fine without needing the screw/hole anyway.

 

[Turkster]

Today i managed to find the 2 in & out pipes just left of the battery, pulled one forward a jar to let the air hole do its job, got the car up to temp and slid it forward a bit and out came a load of air followed by a jet of liquid, pushed the pipe back on tight and put the retaining clip back in its place and the inside of the car is lovely and hot, my water temp gauge also went up to 90 too, so im pondering if there was an air lock in there somewhere too,

 

[AlexGSi2000]

Glad you found the bleed hole.
From your description, there was definatley an air-lock.