Yeah, I'm obsessing about this thermostat. I've read in the past that my thermostat should have a jiggle pin. However, the Mahle 92 C thermostat that I ordered from FCP Euro does not have the jiggle pin.

Should I be concerned?

I'm not even sure what the jiggle pin does. Some sources says "it let's air bleed out" and others say "it's to let a trickle of cold water into the engine so the engine doesn't get shocked when the thermostat opens."

 

The jiggle pin is used for releasing air from the cooling system. Many of the newer manufacture thermostats use a different method of achieving the same thing without the additional point of failure a jiggle pin tends to be. Plus it's cheaper to manufacture and they still get to charge the same price 😁.