Gurgling noise from heater

Hi I am new on here but have, hopefully, a simple problem with my 96 300Tdi Discovery
I have a gurgling noise coming from behind my dash which usually occurs when gently accelerating. A friend of mine thinks there is air in the water reservoir. Is there a simple fix to get the air out?
Any help would be much appreciated as my windscreen does not clear properly at the moment because of the steam! The temperature gauge always remains constant.
Many thanks
Tom

I have an 02 and had an 96 and both made the same noise, it sounds like there is water moving around in the dash, not sure what it is though.

Definately, as there is sometimes (quite often) steam coming out from behind the dash. It stops if I put the heater on recirculate though. If it is leaking it must only be leaking a tiny bit as there is not water in the footwells or anywhere else

If it sounds like water gurgling/running then it's possable there is air in the cooling system usually in the heater matrix as it's one of the highest points in the system u will need to bleed the cooling system to remove the air. Turn the heater controls to hot, remove the screw cap on top of the rad and start the engine and watch for the bubbles then topup the coolent and replace the cap. I understand that Tdi's also have a filling cap also on the thermostat housing.

It may help to unbolt the header tank and hang it up with string as high as the hoses will let you when refilling,extra header pressure and all that .In the solihull workshop book!

thanks for your help. so i have not necessarily got a leak which is causing the steam from behind the dash ??

Tom79 said:

thanks for your help. so i have not necessarily got a leak which is causing the steam from behind the dash ??

Click to expand...

We forgot that one, you should not have steam comming from the dash.

So there may be a problem with the heater matrix.

Here, Discool, you say to...

Turn the heater controls to hot

Click to expand...

...and I was wondering why? I thought that hot water always flowed through the matrix and the heater controls just directed the air.

And Tom, I'd suggest that water is escaping from the system somewhere to create the steam, are you losing any from the header tank?

The best way I've found to get the system bled is to:
1. Make sure the header tank cap is firmly screwed on.
2. Unscrew the plugs from the top of the thermostat housing and radiator (if they're plastic ones be careful, or go and by some brass replacement fittings).
3. Top up through the thermostat housing until water comes out of the rad with no bubbles.
4. Replace the rad plug and continue topping up through the thermostat housing.
5. When the bubbles stop coming out of the thermostat hole (and you have to wait a bit, water is thick stuff) replace the cap and top up the header tank.
6. Run it for a bit, then with the header tank cap still on check the levels in the thermostat house and radiator.

Six stages to topping up your coolant, got to lurve it~!

also check breather hose havent come off its by the pipes from the matrix to bulkhead but sounds like a leak as i had steam from dash and found hole in bottom of matrix the coolant may be getting soaked up in the sound proofing as it is quite thick and there is a drainage hole under sound proofing although it usually has a plug in it

DomEllis said:

Here, Discool, you say to...



...and I was wondering why? I thought that hot water always flowed through the matrix and the heater controls just directed the air.

And Tom, I'd suggest that water is escaping from the system somewhere to create the steam, are you losing any from the header tank?

The best way I've found to get the system bled is to:
1. Make sure the header tank cap is firmly screwed on.
2. Unscrew the plugs from the top of the thermostat housing and radiator (if they're plastic ones be careful, or go and by some brass replacement fittings).
3. Top up through the thermostat housing until water comes out of the rad with no bubbles.
4. Replace the rad plug and continue topping up through the thermostat housing.
5. When the bubbles stop coming out of the thermostat hole (and you have to wait a bit, water is thick stuff) replace the cap and top up the header tank.
6. Run it for a bit, then with the header tank cap still on check the levels in the thermostat house and radiator.

Six stages to topping up your coolant, got to lurve it~!

Click to expand...

Yes I know what u mean a bit of dis-information there . I was still in a bleeding RR 3.5 mode where the heater temp controlled the flow of water.

Which was the last time I had to bleed a cooling system, the disco 3.9 is a lot better as it self vents through the expansion bottle cap.

Update : The coolent does not circulate through the matrix when the temp control is set to cold on a disco. The same as a RRC then. But this may be just for the V8's.

I have steam through the dash all the time hot or cold! I am going to try and have a look now. The breather hose seems likely as I can see some steam coming from the back of the engine in the engine bay...

Well I looked through from under the drivers side of the dash and could see it was quite damp in there so as a temp fix I have disconnected the hoses and used a bit of copper pipe recirculate the coolant through the engine. Not ideal but i can drive it without plumes of steam coming out!

If anyone has a heater matrix for sale please get in touch, or if you know the best way of taking it out.