My car thinks that the coolant is low

[Brett Dikeman]

At 12:41 PM -0800 1/14/01, Mark L. Chang wrote:
>Sounds like your car has a multifunction temperature sensor that has gone
>bad. On my 90q20v, this MFTS does three things (I've been told): overheat,
>low coolant, and analog guage on your dash. So, it can fail three ways (or
>so I've been told).

Close:
-stage 2 fan speed
-overheat
-dash gauge

The first two functions are performed by a wax expansion valve in the 
tip, which presses a cantilever; the lever works two limit switches.

The dash gauge is driven by a small disk type thermal sensor, 
grounded to the brass body inside, sitting inside a springloaded tube 
that's part of the plastic body(picture a lock tumbler type 
arrangement.)

The "low coolant" function is handled by a sensor in the tank.

>
>I had mine replaced last October and it's dead again. It seems that there
>was a bad batch, as it's not just me.

Just a poor design.  I dissected one(as evidenced by my description 
above :-), if you search the archives carefully you might find it. 
The curious can rip it apart as well, just use a dremel tool around 
the brass, almost near the "base"(plastic end.)  The brass is crimped 
over the plastic to hold the whole thing together; once you cut a 
small ring of brass off, the sensor pulls apart.  I would not waste 
time trying to repair the sensor, its functions are too important and 
it would be too hard to reassemble.


Brett
-- 
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Brett Dikeman				Systems Engineer
ProAct Technologies Corporation		914-872-8043
(formerly CFN[formerly iClick, Inc])		914-872-8100(fax)
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