[urq] RE: Water temp

[James Howard]

If the after run pump flows in the opposite direction to normal water flow,
does it have a check valve to prevent coolant running through it (from the
main pump) while the engine is running and therefore bypassing the
thermostat?
If there is a check valve, maybe yours is broken??

Jim.
----- Original Message ----- 
From: "Phil Payne" <quattro at isham-research.com>
To: "Ned Ritchie" <Q at IntendedAcceleration.com>
Cc: <urq at audifans.com>; <quattro at audifans.com>; <200q20v at audifans.com>
Sent: Saturday, January 10, 2004 12:09 PM
Subject: Re: [urq] RE: Water temp


> > 1.  Start with known good 87 C degree thermostat
> >     (Don't use cooler version sold everywhere)
>
> Done.
>
> > 2.  Use known good "correct" value fan switch in radiator
> >     (The higher temp one)
>
> Done
>
> > 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.
>
> Done.
>
> > 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
>
> Done.
>
> > 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
> closed?
>
> It looks to me like the afterrun pump bypasses the thermostat.  Fine - but
could it account
> for this kind of flow?
>
> --
>   Phil Payne
>   http://www.isham-research.com/quattro
>   +44 7785 302 803
>
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