1.3 mpi over heating

[per ardua]

Help!! my mini P reg 1.3 mpi is pushing water out of the header tank . I have changed the head, had it skimmed and as soon as the engine get warm it forces water out the header, could this be a blockage, do i need to bleed the system?. if so how.

[DanGT]

The only time I have had the same problem it was the head gaskit. I would run water throw the diffrent systems and check water flow. Also check the thermostat, remove and run and see if all is ok?

Hope this helps

[PGM]

My brother had this with his head gasket too.

[Cooperman]

Either head gasket or thermostat. Check the stat first by taking it out and chucking it in a saucepan of boiling water. It should open up. If it does not, then it's U/S (or f****d as they say in the trade).
Otherwise it's 'head-off' and have a look.

[per ardua]

Thanks for the advice guys, i now believe it could be an air blockage as the hoses to and from the heater matrix are cold and the heaters are cold. does anyone know if there is a bleed tap/screw any where on the system.
cheers again Mark

[DanGT]

Minis (I have not worked on a mpi) don't have bleed points. Taking it that there are no modifications eg the pipes run in a none standerd way, its probably still the thermostat. Could be a blocked matrix but less lightly. If the thermostat is not opening then only a small amount of water is flowing round, so not much heat.

[minimadmotorman]

I had an MPI where the cast impellor on the waterpump detached itself.

May be worth checking for the cost of a gasket.

[FWDRacer]

Have you tried running the motor (stationary /Idle/raised rpm) with the cap off to allow the air to vent? Can work, keep an eye on the temp gauge.

[dendyb]

Hi there,

Does your cooling fan come on? If it's not switching on to cool the radiator, then you'll overheat. The temperature sensor failing is a common fault. I've had 2 die in 2 years. If you need to replace it (and it washer!), it's got a brown plug and is at the right of the cylinder head near the thermostat.

[per ardua]

Fellas tried all the above, still got the same problem as soon as the temperature get to normal the coolant pushes out of the header past the cap. I am going to flush the system, if this doesn't work its head off again!!!

[Cooperman]

Change trhe thermostat before doing anything else.

[per ardua]

Cheers cooperman, could it really be that simple? i have tried running it with out a thermostat and it done the same.

[Cooper1999]

per ardua, I may be mistaken, but if you're running without a thermostat don't you need to utilise an adaptor plate/choke device of some sort?

[DanGT]

With out the thermostat it will just take longer to heat up. I think most would agree it got to be the head gaskit. On a car with an expantion tank the give away is bubbles (not the munkey) in the water. Dont know how you would test on a mini?

[FWDRacer]

Does your coolant whiff faintly of exhaust gases?

[per ardua]

FWDRacer said:

Does your coolant whiff faintly of exhaust gases?

I dont think so, i will be doing a sniff test as soon as i get the kit from a mate

[per ardua]

I think the fault may be the temperature sender in the thermostat as the fans not coming on . But when i bypass the sender and run the fan constantly i have no problem.Could this be the problem? Let me know what you think!