Mini ONE 1.4d: Bubbling from radiator bottle... is it the cylinder head?

 

So today we have a MINI ONE 1.4 diesel and guess what... it's overheating! Coolant is being lost somewhere and we find that it is bubbling out of the header-tank. My first guess in this situation is the head-gasket, but for a cheap fix (possibly, but better than going straight to ripping a friend's car apart) we tried a new radiator / header-tank cap, which was fitted yesterday and, although it has reduced the bubbling problem, there is still some coming out when the engine is warm, coolant lost and the temp. needle creeping up. 

This week the poor running has begun... occasional juddering, drop in revs and the odd misfire noise. Hmm... I have said to keep using it until the running becomes unmanageable (provided it's kept watered and is not overheating of course!) and am hoping for a weekend of better weather so I can have a proper look round it and, if need be, open it up. Watch this space.

EDIT: With not many tell tale signs of the head gasket being blown, someone has kindly suggested that the water pump is failing and not circulating coolant properly, so here's something else to look into. Yay!

E46 Clubsport: Loss of coolant... split radiator!

The Clubsport is starting to become a bit 'whatever next' lately. Amidst the other post new year jobs I forgot to mention the coolant expansion-tank that sits next to the radiator had swelled and split down one side, so a new one was duly fitted.

Last week the sudden loss of coolant returned, with the puddle in the same place under the radiator, but no visible sign of a leak. Nath assumed it to be the radiator-cap, so we pressure tested it in work and it's fine. Then we pressurised the rest of the cooling system and this is what we found - the radiator has burst along the top. A new radiator is going straight in, but the fact remains that something is still pressurising the cooling system and needs to get sorted.