[Healeys] Overheating query

[Michael Salter]

Hi Simon,
It is very unusual for a water pump to stop pumping, I had that happen once
on a TR7 but that is  totally different type of pump. I would imagine that
it could happen if the impellor came loose on the shaft but then the seal
would almost certainly start leaking..IMHO forget the pump.
What you are describing sounds very like a thermostat failure. I haven't
studied the Smiths (retro) type thermostats closely but many earlier
designs of thermostats had a very bad design flaw in that they used to go
to the "closed" position when they failed.
I'm pretty sure that most modern thermostats are of the "fail safe" design
in that they fail in the open position.
The easiest test is just to remove the thermostat and see if the
overheating goes away.
To test the thermostat put it in a pot and bring the water temp up to the
boil ... you should be able to see the thermostat open before the water
boils.
Hope that helps..
M


On Wed, Sep 7, 2016 at 12:19 PM, Simon Lachlan <simon.lachlan at homecall.co.uk
> wrote:

> Hi,
>
> This isn’t the usual one ....”my car always runs hot; what’s the cure?” etc
>
> No, this is my very own original.....
>
> Background:-
>
> 1)      The car, MkII BT7, has never had overheating issues before today.
>
> 2)      It has a new, 12 month, modern design radiator.
>
> 3)      It has the correct type(original design) Smiths sleeved
> thermostat. (5 years old +/-).
>
> 4)      The waterpump was in the car when I bought the car +/- 25 yrs ago.
>
> Today’s symptoms:-
>
> 1)      I took it out to the pub today and, on returning, I noticed that
> there was HEAT and then that the gauge was off the scale.
>
> 2)      There was plenty of coolant in the rad and it didn’t seem overly
> hot.
>
> 3)      I didn’t have much time, but I got the impression that the rad
> was not blowing steam or making more of a “cooling-off noise” than usual.
>
> 4)      I also got the impression that the engine was hotter than the rad.
>
> Is this typical of a failed water pump?
>
> How can one differentiate between thermostat issues and waterpump issues?
>
>
>
> Any ideas?
>
> Simon
>
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>


-- 
*If you can't fix it with a hammer, you've got an electrical problem.*
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