Mini 55 plate heater issues

[Cocobear74]

I have just started owning a Mini cooper 55 reg and am puzzled by the recent issue.

Was driving for 45 minutes the other night and the heater went cold and wouldn't blow hot the following day either. Parked it on my father in laws drive and we had a look under the bonnet. Both top and bottom hoses where flat, unscrew the bleed screw on the top hose and it was just steam we topped it up and i gave it a run and it became warm. Drove it the next day and was warm again no issues and no abnormal temp reading.
Just checked the hoses and they are flat again and the top radiator hose is cold so we checked the bleed screw and it required topping up again as nothing came out when we unscrew it. Header tank was normal and no water was needed to be added.
Am I missing something with this as my heater has blown cold air again.

Any help would be greatly appreciated.

[GreenV8S]

Any time the heater won't blow hot you need to make sure you have coolant circulating before you drive it any further. You can kill an engine very quickly if you drive without any coolant flow. In your case it sounds like you are losing a lot of coolant. If it's an external leak you may be able to fix it without any engine damage if you get to it soon enough. But by now there's a chance it's already too late.

[Cocobear74]

Thank you for the reply.

I have a 12 mile journey to work and have checked the reservoir tank when I arrived and it was at the normal level with no loss but the water was cold. I am assuming this is normal?
I unscrewed the bleed screw a little and water did come out so that is up to pressure and doesn't require a top up or show I am losing water in the engine as we topped it up yesterday.
The heater is working fine and the temp gauge is normal.

[GreenV8S]

Maybe I mis-read - I thought you were having to top it up.

[RazerSauber]

Losing that much coolant would produce a noticeable drip. If you can't see a drop underneath then it may well be head gasket. Have you checked the dipstick and oil cap for the tell-tale "mayonnaise" buildup? Check your foot wells for water too, in case your heater matrix has thrown its hand in.

Last experience I had of a coolant leak was the thermostat housing leaking. Not a hard fix but a little fiddly. Requires the removal of the air filter box and battery box to get to properly, or some acrobatics with a socket set.

Make sure you're bleeding BOTH bleed screws too, there's one towards the left hand side of the battery box (which is a bit more difficult to see) and one right in front of the engine. When your engine is cold, check there is coolant under the high pressure cap which is located to the bottom left of the battery. Black cap full of warnings, requires a little effort to undo. This is your thermostat housing too, check all round it for crystallized coolant.

Flat hoses says to me that there's a vacuum inside your engine somewhere.

[Cocobear74]

Much appreciate the reply.

I will be checking it at regular intervals now to see if I am losing any more water or it was just a one off. It is coming winter now so will need anti freeze adding so be best to take it to a garage and have it done correctly .