head gasket

[powerandtorque]

You shouldn't really ever need to top up the cooling system once it's been filled and bled through, and IMO if you're ever having to add notable amounts of coolant then you've got a problem - either it's leaking or it's being burnt.

I agree with Ruan - if you really had to add 5-6 litres in a single hit after driving it home then the HG will be toast and you're throwing good money after bad continuing to put fresh coolant in it. XU's and especially XUD's just won't take being run low on coolant and continuing to be driven, even if the gauge never shows that's it's overheating as there will be localised air pockets and temperature variations. Every time I've seen someone continue driving critically low on coolant it's always been a case of when, not if, the HG subsequently shows signs of failing.

By the time the heaters start blowing cold you're already on borrowed time really, but if you're in that situation again stop the car there and then and you might just save the engine. Continue to drive and whilst you'll probably make it home, the damage will be done.

Hate to say but if it was like that when you bought it then chances are the seller knowingly sold you a pup