excessive air? head issue?

[DA55TER]

OK....so I posted about the loss of water my 55 plate 2.0tdi. I've had the water pump replaced, the cambelt done, a new expansion bottle and thermostat fitted.... now the weird thing before you say "its the head" the water level is perfect, the car heats up after a journey, and the low coolant lght comes on. I stop the car at home relieve the pressure. Wait until the car has cooled down completely, and open the expansion bottle again. The water level returns to on the Max mark.... so its not
Losing water, its gaining air, which in turn forces all the water out the bottle.
Is that a head issue? I dont want to spend money on the head, only to have the issue return....

Please help. Supposed to be driving to France for the winter in the car.
Oh... and the last digit on the head number is C.

Cheers

 

[WALTO TDI]

Get the coolant system pressure tested mate.

 

[Chillout]

Cooling systems are pressurised as water boils at a higher temperature when pressurised so it could be normal.

 

[DA55TER]

Cooling systems are pressurised as water boils at a higher temperature when pressurised so it could be normal.

Pressurized to the point of forcing all the coolant out of the expansion bottle? I'll try to link a video of what happens.

 

[Chillout]

Pressurized to the point of forcing all the coolant out of the expansion bottle? I'll try to link a video of what happens.

Missed that bit take it you have no air locks ,blockages ,good flow and the thermostat is good.

 

[DA55TER]

Yeah. Had the system flushed when I had the water pump done. New coolant etc. What would cause a blockage?

 

[Jack_tdi]

I have a similar issue on my 06 tdi but I carefully release pressure while it's hot and add 500 ml to 1 ltd about once every 6 weeks will be interesting to see if you find any issues....

 

[DA55TER]

I have a similar issue on my 06 tdi but I carefully release pressure while it's hot and add 500 ml to 1 ltd about once every 6 weeks will be interesting to see if you find any issues....

Well the part that baffles me, is the fact that the head on my car is a "C" serial number. Which according to another thread. Is an 06 head... mines an 05 car. So my thought is the head has been replaced alread?

A guy I work with is a marine engineer. He said airlock. A few people have said airlock. So im gonna run the car with the cap off, and see what happens when the thermostat opens. Whats the serial number on yours Jack?

 

[B5NUT]

My 1.9TDi had the same problem, car would drive fine start and if left to idle it would get up to temperature and have no excess pressure in the coolant system. However once I started to drive the car the pressure would start to build up and the faster I drove the worse the pressure was. The fault was the head gasket, the coolant pipes are expanding due to the pressure and that is where your water is going, the other thing could lead to is a premature failure of the hoses, radiator & heater matrix which is a ****** of a job. I would get this looked at ASAP as it could end up costing your more money in the long run.

 

[DA55TER]

My 1.9TDi had the same problem, car would drive fine start and if left to idle it would get up to temperature and have no excess pressure in the coolant system. However once I started to drive the car the pressure would start to build up and the faster I drove the worse the pressure was. The fault was the head gasket, the coolant pipes are expanding due to the pressure and that is where your water is going, the other thing could lead to is a premature failure of the hoses, radiator & heater matrix which is a ****** of a job. I would get this looked at ASAP as it could end up costing your more money in the long run.

Got it booked in for Monday. Gonna pull the head and have a look. More than likely, whoever fitted the new head, was a ****, and did a shoddy job of it. Fingers crossed.

 

[DA55TER]

Video of my expansion bottle at full operating temp.
https://www.youtube.com/watch?v=gbo9cKxmHug&feature=youtube_gdata_player
So when the bottle is closed, that air builds up and forces all the coolant out. Could that pipe be blocked?

 

[B5NUT]

No, something is forcing air into the coolant system. A blocked pipe would not allow air into the coolant system, it would most likely cause the car to over heat, as the coolant could not flow around the system correctly.

 

[DA55TER]

I hope to hell its the head. I'll be properly miffed if I spend money having it done, and it does the same thing....

 

[sliced]

I have a similar issue on my 06 tdi but I carefully release pressure while it's hot and add 500 ml to 1 ltd about once every 6 weeks will be interesting to see if you find any issues....

bad move, another member of this forum got some serious burns doing that!

 

[Jack_tdi]

Well the part that baffles me, is the fact that the head on my car is a "C" serial number. Which according to another thread. Is an 06 head... mines an 05 car. So my thought is the head has been replaced alread?

A guy I work with is a marine engineer. He said airlock. A few people have said airlock. So im gonna run the car with the cap off, and see what happens when the thermostat opens. Whats the serial number on yours Jack?

Mine is a revision c too

 

[Jack_tdi]

bad move, another member of this forum got some serious burns doing that!

I'm well aware of the danger of burning myself.....

But iv done this over ten times with this car and hundreds of times on an old rover I had with a k series engine in if you release pressure slowly it won't explode all over you.... Just got to think about it