
For the sake of my sanity (and confirmation) I 'think' my head gasket has just started to let go. Now I've had H/G go before on other cars where you have the typical tell tale signs with sludge under the oil + rad cap etc. However mine doesn't have this, possibly because it's just happened - but the coolant overflow does start to dribble then squirt when pressure's applied. Under the rad cap are frothy air bubbles, so thinking that the gasket has given way between the exhaust > water jacket.
An obligatory photo;

So, all opinions welcome please. Has my H/G gone or maybe I have a warped cylinder head.
