Cooling conundrum

[Huw Powell]

> 1990 200tqa 1b motor (10v turbo)
> Hi I've just fitted an electric water pump to the car which involves milling
> off the impeller from the standard water pump and removing the thermostat.
> The new pump has a probe which I have inserted into the top hose by the
> head, this controls the speed that the water is pumped around the motor via
> a temperature adjustable controller.

uh oh... I have no idea what I'm talking about, but that sounds like a
*terrible* idea.  You need that coolant to keep circulating or you'll
get hot spots in the head, etc.  I think the "real" engine folks will
back me up on that.

> I have a few concerns.
>  The fan is going far too readily and is over cooling the water in the
> radiator which makes said pump go too slowly and therefore the heater is now
> terrible. Where is the sensor for the fan. I believe I need to change it to
> kick in at a temperature above the max I set for the pump controller.

It all sounds scary to me.  You should run your pump at a steady speed
(with maybe an "overdrive" speed if you can control it effectively), and
let coolant in to the radiator with a thermostat - this controls the
engine's operating temperature.

The fan sender is usually in the bottom of the radiator.

> Is the current slow pumping likely to cook up the turbo.
> What would the optimum temp be for this motor.

87 C I think, at least that's when the thermostat opens.

> The dash warning is flashing at me while the analogue gauge is reading fine
> (80 deg C).  This can be either water level or temperature, am I assuming
> correctly that the level is monitored solely off the bottom of the filler
> bottle does disconnecting this bypass it or do I need to close that circuit.
> The temp warning is which sensor and  what parameters trigger it off?
> The warning comes on within 30 seconds of starting the car hot or cold.

Well... I suppose if the *lowest* speed your pump will run at is enough
to avoid hot spots then the concept is reasonable.  But ditching the
thermostat sounds all wrong.  You don't want to pump cool radiator water
through a cold engine, for instance, and running the pump slow enough to
achieve that sounds scary... but maybe you know better what you are
doing than I, too.

the coolant level only runs off the sender in the expansion tank, yes.

the temp gauge sender ought to be in that multi function sender on the
radiator hose neck... the one that always goes bad.

The overtemp warning I'm not sure about on your car...

--
Huw Powell

http://www.humanspeakers.com/

http://www.humanthoughts.org/