Coolant leaking from the coolant tank A4 B6 1.9 TDI

[delc83]

Hi Guys
Audi A4 B6 1.9 TDI 130, AVF, 2004
I've noticed coolant is leaking from the hole under the coolant tank, when ive been driving, it isnt loosing much at the moment, but when I open the bottle pressure comes out and the coolant rises.
Ive have replaced the coolant tank with a new one, still leaking.
I've also replaced the thermostat (genuine), temp sensor, because it wasnt sitting at 90, but is now.
Earlier this week water pump failed, so got that replaced, even though it was replaced at 115k, 7 months ago.
It is still leaking and the coolant has gone a bit dirty, ive had the sniff test done, and it didnt show any hydro carbons, and the colour didnt change and also pressure test on the coolant bottle and pressure was fine.
Hope its not the head gasket, my friend said it could be the oil cooler.
Any help or guidance would be appreciated.

 

[B5NUT]

I had the same problem and it was the HG, its one of the only ways to pressure rise the coolant system and water to be forced out of the coolant bottle, only other cause than I can think of is a cracked head.

 

[delc83]

How much did it cost?

 

[B5NUT]

Did the job myself, so was very cheap. Here is a post head with some estimate pricing http://www.audi-sport.net/vb/a4-s4-...-coolant-loss-head-gaskett-cylinder-head.html

 

[Mollygoogle]

Just had the same symptoms with mine and it was the head gasket. Hopefully yours works out better than mine has so far

 

[pauldazzle]

Head gasket failing.

 

[delc83]

I just dont want to get it opened and have a cracked head.
Is £300-£400 a good price to get the HG replaced? a mechanic said sometimes injectors fail when replacing the HG, ive also been told skimming the head isnt a good idea on a PD engine, is this true?

 

[AudiLeon]

Did you replace the cap?

 

[delc83]

Yes i replaced it with my mates, ive noticed the pipe thats connects to the radiator goes really hard when ive been driving around. its building pressure, only way to let it out is to open the cap, and some air and more coolant comes out the hole from under the tank, and the pipe goes soft again.

 

[BakPak]

Had very similar problem with mine, 1.9tdi 130 5 speed. After giving the coolant system a dose of K-Seal no problems since. Done approx 500 miles. Mark.