Vauxhall Astra: Coolant keeps emptying

[Walterloo]

I have a 2004 Vauxhall Astra Diesel. The coolant reservoir keeps emptying. I refill it with antifreeze/water but it doesn't last long. I have no wet carpets and the car runs fine otherwise, no gunk under the oil cap indicating head gaskett problems, but I have no heating of course! I have purchased some Radweld, thinking there may be a leak in the radiator. The bottle tells me to pour into radiator. My car manual doesn't even mention where the radiator is, so do I pour this into the coolant reservoir itself whilst it's empty, or into the radiator, which I believe is just behind the grille at the very front of the car, between the headlights. If the latter I cannot see any entry point for the Radweld. I will take the car into a garage if I cannot solve this. Please help!

[Panic Button]

It would go into the colant reservoir, when you fill it up.

However your leak sounds too severe for Radweld to cope.

Refill the reservoir, leave the bonnet up and start the engine.

Watch while it runs, and the system pressurises. You may well see where the leak is coming from by looking into and below the engine. It may be a split hose, or a leak from the radiator.

[Postdog]

Just to say you are not alone. I have a rogue loss too, and nothing seems to be wrong. Obviously is, cos I'm having to top up all the time.

My old Vectra I never touched it in all the years I had it, but since I have had this astra....

[razza]

Check engine oil,if it has got a froth inside filler cap it points to a blown gasket.

[Walterloo]

Thanks for all your answers. I will try your advice PanicButton and I hope you get yours sorted too, Postdog, without having to spend a fortune in a garage.

[Booldawg]

'the car runs fine otherwise'; Does it not ever over-heat? Surely this would happen if you're losing water fast?

[Postdog]

I've had the blown gasket already, changed water pump and hoses, tried radweld etc. One day I'm gonna give to amachanic friend and just say see if you can find something wrong!

[TWR]

If possible check the core plugs on the block ( There should be 4) possible water loss from there but cannot see as if a hose has split.

[123everton]

If there are no signs of a leak (usually rust) and the core plugs seem fine (I'd have thought the water would pour out as you fill it with them), given that it's not overheating, I'd buy a new radiator cap.
If it isn't sealing then system isn't pressurised so the water won't go beyond boiling point and the rad will cool it.

[S_C]

After filling the car with water lift the bonnet and leave the car running when it is Warm " normal running temp "and showing show on the instrument panel inspect under the bonnet while the engine is still running at all joints and hoses " be careful its not going to be cool and remeber it will have moving parts. any leak should become apparent by checking teh ground for the water dripping this will give you a general idea of where abouts the water is coming from and hence where your leak is. i Emphasise the Warm as this will bring into play the hoses and any pipes and fixings that work " after the thermostat has engaged" as prior to this any leak there may not be so apparent and could easily be overlooked.

[S_C]

if after checking for leaks , " if you dont find one " also check your dip stick " oil " and make sure the oil has no creamy white resude in it " this can indicate both lack of airation and water in the oil . If water is found seak a garage immediately to ensure no further damage is caused by using the vehicle in such a state