31 replies to this topic

[WillsMini]

I have just bought my first mini in over 20 years, a 1985 City 1000.
It's in pretty clean condition and runs well but temp gauge reads hot after only a few minutes. I am guessing that the water pump is kaput. I get no heat on the inside of the car and can see no water movement in the rad when the engine is running. I plan to remove and flush rad and flush the block.
Any other advice anyone can offer? Am I in the right ball park or missing something completely?
Thanks in advance.

[fattail95]

I have just bought my first mini in over 20 years, a 1985 City 1000.
It's in pretty clean condition and runs well but temp gauge reads hot after only a few minutes. I am guessing that the water pump is kaput. I get no heat on the inside of the car and can see no water movement in the rad when the engine is running. I plan to remove and flush rad and flush the block.
Any other advice anyone can offer? Am I in the right ball park or missing something completely?
Thanks in advance.

I reckon you're right, have a look at the water pump :)

[Ipod]

Check thermostat

[WillsMini]

Changed stat. Was almost welded in so obviously hadn't been changed in a while. I hope a good flush through will do the job. Perhaps a new pump if anything else. Cheees guys.

[KernowCooper]

Are you sure when the gauge goes up in such a short period of time the waters actually that hot and the sender units not giving a false reading, if theres no water flow through the rad then the thermostats either not opening as the water not reached the opening temperature to open the thermostat.

 

With the new thermostat fitted run it up and see if the gauge reads high as it used to, then if it does check the water temp with a thermometer and if cold and gauge reads high, change the sender unit

[tiger99]

What you are doing with the cooling system is good (you may be surprised how much rust, muck and debris comes out when you flush the system) but also give it a general tune-up, i.e. valve clearances, points and plugs, timing and mixture adjustments, and it should run a bit cooler and more efficiently. Weak mixture or retarded timing will make it run hot, and these"old-fashioned", i.e. non computer-controlled engines, with carburettor and points, do go out of adjustment.

[WillsMini]

Thanks for the rapid responses.

[Cooperman]

Let us know if you solve the problem. If not more advice will be forthcoming if requested.

The big question is whether it is actually running hot. The electrical sender unit and the voltage stabiliser have both given problems in Minis and many have fitted the 'capilliary-type' gauge as supplied by Mini Spares. That gives a reading in degrees C which is better than C-N-H.

[WillsMini]

Took rad out yesterday. Flushed, not blocked. Old but not leaking.
Water pump seems good. No leaks, spins freely and system is pressurising (does this mean it's ok?).
Still getting way too hot within only a few minutes. Bottom rad hose hot, top hose cold. Water in rad cold. Engine glowing (not really but you know what I mean). No warmth from heater.
All I can think is no water circulating round block.
Next plan to remove pump and flush block. Any advice re. the flushing part?
Then strip and tackle heater see if that causing any issues?
I have wondered if it may be an air lock. Could that cause this issue? How do I sort one?
Any advice very welcome. I'm beginning to think I've bought a lemon! :-(.

[tiger99]

The heater is very likely to be a simple air lock. However, that has very little to do with the main problem. The heater should not be needed to cool the engine.

 

I would suggest a very thorough flush of the block. Remove thermostat for now, to eliminate it, as even new ones can be defective. Reverse flush first, stick a hose into thermostat housing and allow water to exit from bottom hose. Then forward flush, the other way round, for good measure. You can also stick the hose on the heater takeoff on the head (if that is where it is on your car) and flush through there.

 

Once you know that water can flow freely through the block and head in every direction, connect up the hoses, fill it up and try again. I suggest using plain water for now to avoid wasting antifreeze, but once the problem is solved you should replace it with the correct antifreeze mixture to reduce corrosion.

 

If it then runs cooler with no thermostat, it is time to put a new one in. Don't run it long term without the thermostat, or the special blanking sleeve, as you will get non-uniform cooling of the head, which will do damage, but it is ok to run for a short time without.

 

The heater is most easily sorted out by loosening the highest hose connection, and with the engine running (preferably cold!), removing it briefly, until water is running out, then reconnecting quickly. Or flush it through with your hose until it is running freely, and connect quickly.  Some people plumb in a bleed valve at the highest point of each hose. Modern cars solve the problem by running a small hose from each high point in the system to the header tank, so trapped air can always rise and escape.

[WillsMini]

Thanks for taking so much time for posting great, helpful advice. Will try all and post results.

[mini_zinger]

my mini over heated today i am in NZ and totally new to fixing minis, loved minis since i was 8 yrs of age. dont know where to start, car had to be towed.

 

From the reads on this forum, it seems pretty easy to remove radiator and water pump and thermostat.

 

I saw water leaking from water pump when i opened bonnet. very rusty coloured water. So my guess is water pump definitely needs to be replaced. But how do i know if my thermostat needs replacing as well?

 

And radiator?

 

Thank you heaps in advance.

[mini_zinger]

also if someone could help me with step by step guide to changing thermostat and water pump please it will be very helpful or direct me to a link that has these steps

[mini_zinger]

i think that due to water reaching high temp, it needed to escape and this is when water pump gave up and hence the heated water came out from there.

 

if this is the case then will the pump need replacing or is it just the gasket for the water pump? how would i know water pump needs to be replaced?

 

also to mention, i could hear squeaky kind of noises, hard to describe this, before it all heated up. example of sound would be when you take a plastic bottle and rub it against a hardened plastic bucket.

[mini_zinger]

i think i mean squeaky noise, now i think it was the belt, as when the water pump leaked water on to it, it was squeaking :)

 

please do help me with all other questions above