Thought I posted this yesterday but no sign of the post so will try again. My elderly mother's Matiz has a problem that would seem to be either head gasket or an airlock somewhere. On checking the oil the expansion bottle had brown stains around it, and was low on coolant. I topped it up and drove around for a bit to warm it up. On revving the engine the coolant began flowing out of the top of the bottle.
Brown stains obviously mean corrosion somewhere, and something isn't right. She doesn't live locally to me and has been advised by her mechanic that it should be ok to drive provided she keeps it topped up with coolant, until he can fix it in 3 weeks time. I'm not so sure.
Any thoughts appreciated. The car was not obviously overheating, is used irregularly and has done around 16k.