Fans not coming on upon shutoff
09-11-2013, 02:09 PM
#16
Team Owner
Copied to make it easier to read,
thanks for taking one of these apart.
+1 to Alan's and dr bob's comments.
I have just machined the top off a failed temperature switch (after another 928S4 owner washed his engine.
The switch is a spring loaded fulcrum contact switch operated by expansion of and internal piece contained within the bottom of the switch.
The failure of the switch was caused by debris washed in with the water and lodged between the contacts of the switch.
In some switches the two spade connectors embedded into the plastic like piece can turn with the brass body ,
as the brass body has not been rolled tightly over this switch insert to form a water tight seal.
I cleaned up the switch mechanism and internals and tested the switch by hand and the resistance was nearly zero.
On closer study these switches are repairable by machining off the top rolled section of the body,
machining up a cap piece and soldering the cap piece in place after cleaning up the switch mechanism.
The temperature setting is via a dimpled former applying pressure to the bottom of the switch until the switch trips at 85 degrees C.
thanks for taking one of these apart.
+1 to Alan's and dr bob's comments.
I have just machined the top off a failed temperature switch (after another 928S4 owner washed his engine.
The switch is a spring loaded fulcrum contact switch operated by expansion of and internal piece contained within the bottom of the switch.
The failure of the switch was caused by debris washed in with the water and lodged between the contacts of the switch.
In some switches the two spade connectors embedded into the plastic like piece can turn with the brass body ,
as the brass body has not been rolled tightly over this switch insert to form a water tight seal.
I cleaned up the switch mechanism and internals and tested the switch by hand and the resistance was nearly zero.
On closer study these switches are repairable by machining off the top rolled section of the body,
machining up a cap piece and soldering the cap piece in place after cleaning up the switch mechanism.
The temperature setting is via a dimpled former applying pressure to the bottom of the switch until the switch trips at 85 degrees C.
09-12-2013, 11:01 AM
#18
Randy,
Unfortunately my IPhone belonged to St Peter, as it is that old and has no macro settings.
Tried to take photos with digital camera, however flash flare make it impossible to see switch mechanism and then battery run flat.
Decided to take the day off and went sailing all day, so will recharge camera, take photograph in good light and then post better photos.
It will be interesting to see how the repair goes after soldering on a bonnet and note what differential there is in temperature switching.
Unfortunately my IPhone belonged to St Peter, as it is that old and has no macro settings.
Tried to take photos with digital camera, however flash flare make it impossible to see switch mechanism and then battery run flat.
Decided to take the day off and went sailing all day, so will recharge camera, take photograph in good light and then post better photos.
It will be interesting to see how the repair goes after soldering on a bonnet and note what differential there is in temperature switching.
09-12-2013, 03:56 PM
#19
Chronic Tool Dropper
Lifetime Rennlist
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Lifetime Rennlist
Member
For us mere mortals, a new replacement switch is still readily available from the usual suspects.
I do know now to put a thin smear of electrical-grade silicone sealant around the cap and the terminals. And drop a rubber glove finger (mechanics-grade switch condom...) over that switch if/when I decide to give the engine bay a bath again.
I do know now to put a thin smear of electrical-grade silicone sealant around the cap and the terminals. And drop a rubber glove finger (mechanics-grade switch condom...) over that switch if/when I decide to give the engine bay a bath again.