[urq] RE: Water temp

Phil Payne quattro at isham-research.com
Sat Jan 10 07:11:06 EST 2004

> 1.  Start with known good 87 C degree thermostat
>     (Don't use cooler version sold everywhere)


> 2.  Use known good "correct" value fan switch in radiator
>     (The higher temp one)


> 3.  Use known good MultiFunctionTempSensor
>     (New ones can be bad right out of the box)

Done.  Tried three - existing one, one from a scrapper and a new one.  Same results.

> 4.  Make sure series fan resistor pack is good.


> 5.  Allow engine to idle and the fan to cycle.
>     Stock gauge will read 87 C degrees
>     About 11:30 'o clock on the stock gauge


> 6.  Disconnect stock plug from MFTS and use after market one.
>     (should read the same if of the same calibration)

Not done.  Actually wires inside give cause for concern.

> Be sure to handle the other functions of the MFTS.
> Be sure to only use 1 temp sensor as two in parallel will not give the
> same results.

I'll play with the last bit, but I don't think mine is a gauge problem.  I changed the
thermostat and got exactly the right behaviour at stationary idle - fan cycling, gauge
correct - with the exception that the radiator seemed to start getting hot right from the
start - radiator too hot to touch, cam cover still cold?

When I drove off (ambient 2 degrees C, humidity high and thus wind-chill high) the gauge
rapidly dropped to just above the first mark on the dial.

It's almost as if the thermostat has been omitted.  I've see cars without thermostats,
perpared for desert use and re-imported to the UK without the thermostat being changed.  One
Sport and one UR like that.  This is that kind of behaviour but on an MC-2 engine with both
its old and a new thermostat.  How can I be getting radiator circulation with the thermostat

It looks to me like the afterrun pump bypasses the thermostat.  Fine - but could it account
for this kind of flow?

  Phil Payne
  +44 7785 302 803

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