7 replies to this topic

[djmonkey]

Austin Mini Mayfair with a 1275 engine swap:
1987:

The car has been on my driveway for a few weeks and whenever i start it up, it overheats. Took it for a drive today and it was ok, but when i hit some traffic or the lights the temp began to creep up. ive changed the thermostat, the housing and the fan blade. i took the rad off and flushed it. filled i up with a good mixture of blue antifreeze. pretty sure ive expelled all airlocks, as i had this issue with my previous car. top hose is hot, bottom hose is hot.

i read about it possibly being a lean mixture, i fiddled with the screw on top of the carb so thought it might be this. but my plugs are black and after ive pushed the choke back in the revs sit at 1100/1200.

i cant figure out what it could be.

any help would be great

thanks.

[AVV IT]

Water Pump ??

[Big_Adam]

Silly question.

Your fan DOES have all its blades right? If its overheating in traffic, I'd look at the rad itself and fan check they are all good.

[mikey72]

Water pump, or blockage somewhere.
Get the top hose and thermostat housing off, and the bottom hose off, turn off the heater in the car, put a hosepipe in the bottom hose into the pump, turn it on and see if water comes out of the thermostat housing. if it does, it's not blocked, and then I'd change the pump. to be honest I'd probably change the pump as well while you've done the rest.

Edit - you have got the fan blade on the right way round?

Edited by mikey72, 07 November 2010 - 05:18 PM.

[djmonkey]

thanks for the help, the fans brand new, and is definitely on the right way round as the guy at minispares highlighted the "engine side" for me. rad is pretty old but im pretty sure its good as i flushed it and no gunk or anything came out. gonna get onto minispares for a pump i think.

cheers again.

[bmcecosse]

You also need to clean the external fins of the radiator - if bunged up with oil/leaves it's hopeless.

[Cooperman]

How do you know it's overheating? It could easily be the gauge or the sender unit. The only truly accurate gauges are the capilliary type ones whichn give a temp reading in deg. C. The elecrically operated ones are notoriously inaccurate.

[mk=john]

How do you know it's overheating? It could easily be the gauge or the sender unit. The only truly accurate gauges are the capilliary type ones whichn give a temp reading in deg. C. The elecrically operated ones are notoriously inaccurate.

Check the radiator cap also. if it is leaking then it will not hold the pressure properly, and the water will boil instead of being able to carry heat. Water under pressure raises the boiling temperature and it is more efficient at transferring heat (cooling)

Is the water level OK? If so, the cap should be OK