I am installing a new thermostat. The unit sold to me looks unusual, to my limited experience, and does not look the same as the one I took out: the opening is not centered. There is a narrow side of the flange and a wider side directly opposite. On the wider side is a small hole with a loose brass pin through it. Should this thermostat be inserted in the hole any particular way or just dropped in? It is a Stant.

Posting pics would help

Originally posted by ZwolleY

I am installing a new thermostat. The unit sold to me looks unusual, to my limited experience, and does not look the same as the one I took out: the opening is not centered. There is a narrow side of the flange and a wider side directly opposite. On the wider side is a small hole with a loose brass pin through it. Should this thermostat be inserted in the hole any particular way or just dropped in? It is a Stant.

Attached Picture and text Quoted from Dr. JR Demers website:

Thermostats

Thermostats are cheap. If you think that the thermostat is your problem (car immediately overheats in city or on highway) then replace it. However, some thermostats are cheaper than others. Here I have a picture of an OEM Nissan thermostat and a Stant thermostat side by side. The differences in their construction are obvious and surprising. First, and most importantly, the aperature on the OEM thermostat is around 30% larger! Assuming that they both open the same distance (I actually think the OEM opens further since it is taller) means that the flow through the OEM thermostat is much greater.

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Neither Haynes or FSM specifys a particular orientation for th Htermostat, but I always install them with the opening mechanism oriented to the rear (as viewed from the front of the car) of the housing.

If your car had a thermostat with the opening "centered", well; it was the wrong thermostat. As you can see from the picture, neither the Nissan or Stant thermostat has a centered opening and the Nissan unit has a larger opening than the Stant model shown.

Thanks Carl. The old thermostat does have the centered opening. I put the Stant in for now, maybe later will replace with a Nissan if I need to.