8 replies to this topic

[915Davidg]

Hi All,

 

So I bought my first mini in the summer   but have had non stop problems with overheating since. If I drive it for 5 mins in stop/start traffic it boils over and loses coolant. So I have replaced the following so far but still no fix:

 

- Thermostat

- Thermostat harness/ wiring

- Temp Sensor

- Expansion tank/ 2 x caps

- Water Pump

- Radiator

 

I have also taken it to a garage to check the head gasket and that all seems fine. They seems to think it could be a faulty ECU because the fan is coming on too late. One more thing to note is the temp gauge in the car isnt readin properly (barely moves even when overheating).

 

Any ideas welcomed and I can't think of anything else

 

Thanks in advance,

 

David

[pete l]

The fan is coming on then ? if it is, then you probaly have a coolant system that is not getting up to pressure, so it will boil at 100°c.

 

A system under correct pressure will not boil until over 106°c or more. The cooling fan comes on at 104°c.

Edited by pete l, 14 January 2019 - 02:07 PM.

[915Davidg]

Thanks for the reply.

 

Yes the fan is coming on at the correct temp (about 104/105) but by the the water is already boiling in the tank. This is why I replaced the expansion tank/ cap.

 

Any other ideas how it could be losing pressure?

[ukcooper]

heater matrix blocked

Edited by ukcooper, 14 January 2019 - 09:40 PM.

[Fast Ivan]

If I drive it for 5 mins in stop/start traffic it boils over and loses coolant. 

 

 

 

Find where it's losing the coolant from - this is most likely your problem

[Midas Mk1]

Are you bleeding it properly for air? Might have one massive airlock, MPi's can be harder to bleed than earlier minis with side mounted rads.

[915Davidg]

Thanks for your help guys.

 

Have been looking if it is leaking coolant but cant see anywhere (unless it boils over) and all pipes seems to be connected securely.

 

@Midas Mk1 I did think that too so flushed the system a few times and when refilled made sure the heater is pulled out as per the Haynes manual.

 

The heater matrix was replaced before I bought it so wouldn't think it would be that again.

 

Thanks

 

David

[915Davidg]

Thanks for all your help guys, a flush of the heater matrix seemed to cure it :)

 

Now onto the next jobs to get it ready for summer!

[pete l]

So if you cut the water going to the heater matrix the car will overheat again.