[200q20v] RE:Afterrun thermo switch, was Hole in radiator update.
Reid, Les C.
Les.Reid at Centrilift.com
Mon Jul 2 12:33:05 EDT 2001
Update on the bad switch from Blau
Got my replacement thermo-switch from blau.
Before I went to the trouble of installing I did a little test in the
Put new switch aluminum pan w/water and heated water while monitoring
conductivity across the pins. No conductivity all the way to boiling.
Thinking the switch needs magnetic contact.
While hot, put the switch in a steel spoon and that caused conductivity in
the range of a few M-ohms to hundreds of K-ohms.
Cooled off and switch went back open.
Repeated test (in spoon) and found that switch did not close until over
200F. Same high ohm readings as well.
Removed defective switch and ran test with it.
Cold: switch open
Heated water to only 110F: switch closed with basically 0 ohm resistance.
I could actually hear the switch close and it mattered not about being next
to steel or not.
Switch opened again when cooled off.
The new switch is PN 054 919 369B and a note said it was a direct
replacement for 443 959 481.
The defective switch looked a little different (more metal shroud) and had
part number 443 959 481.
I put the new switch on the car and the after run pump has yet to come on
after shutdown. Though it has not been over 85F outside since installation.
Does what I observed make any sense?
What temp should the switch close?
Should the switch read M-ohms or zero ohms when closed?
Was the magnetic thing a fluke? Maybe the switch really closes over 212F and
I just did not get the fluid any hotter, the spoon may have just jarred the
contacts closer in the switch.
> -----Original Message-----
> From: Reid, Les C.
> Sent: Thursday, June 14, 2001 11:26 AM
> To: '200q20v at audifans.com'
> Subject: Hole in radiator update. What did I do? AC prob/ turbo
> bypass pump
> Hi guys,
> Well last weekend I installed my new radiator and put my car back
> I also replaced the after run temp switch and thermostat. My turbo AR pump
> had not been working for a few months and I had previously determined that
> the sensor was bad (as per sjm, pump energized when I crossed the sensor
> leads). Now the AR pump cycles every single time the car is turned off
> (no matter the run time).
> The switch closes too early: with the engine stone cold, I unplugged the
> switch and confirmed it was open, once I started the engine it did not
> take 2 min for the switch to close.
> I got the switch from Blau.
> Has anyone else had problems with the switches from Blau?
> I have not called Blau yet to report the problem, any advise?
> I kept the old switch, so I could reinstall it while I wait on a
> replacement, but that's a pain, I would rather just do the job once.
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