T'Stats - Who you gonna call?

It sounds like overthink to me...

If they have the part you want ... buy it.

If they don't ........................... don't.

These parts are made to cover a huge range of vehicle/applications.

If they happen to be miss catalogued, or work in a manner which you havn't thought of or understood then you would be making a fuss about nothing...I don't spose anyone would be interested, or if they were you'd just be paying another obsessive beuroprat to waste taxpayer's money.

This isn't supposed to sound agressive but it sounds like a 'problem creation exercise' !

I also purchase some non-critical parts from my local AutoZone and encountered a similar problem with a thermostat; the one they recommended versus the one specified in my owner's manual. There was a 10 degree difference. I purchased the one specified in my manual from another source. I've also seen similar problems with radiator caps.

My recommendation would be to stick with the manufacturer's specifications for lots of reasons.

Probably no reason to report it to the emissions regulators. Probably wouldn't accomplish anything since rules vary widely and are generally ineffective where they do exist. I happen to live in a county that requires emissions testing but it is surrounded by others who don't. The majority of the state does not require it and our test is a joke.

Did you forget that the auto makers are in a global market and the emission standards in the US don't apply every where.

Some thoughts about why different temp tstats being used - Increased RPM & Torque requirements resulting in higher compression ratios in the engine, more power. Higher operating temperatures of the engine offering complete ignition of fuel and thereby reduced emissions / complete combustion.

I would use exactly same thermostat that is recommended by OEM.

As I remember, the newer temp spec is around 185-degrees-F as opposed to the former standard of--I believe it was about--165 degrees.

The above temps are totally dependent upon the type and size of your engine, the environment where the majority of your driving takes place.-i.e. desert, mountains, arctic etc etc.

If you don't know what you want, and the Auto-Zone folks can't aswer your questions, then go to the appropriate dealership and purchase the part there.

In days gone by you would use one thermostat in the winter and a different one in the summer. Regional location is also an issue. With newer vehicles, they generally spec one thermostat temp and autozone is definitely not the place to go to get what you need. The aftermarket thermostats for Dodge/Chrysler are not the same temp as the factory counterpart and are designed differently. They run cooler and will not allow your engine to warm up properly in cold conditions. The factory thermostat is designed to fail in wide open mode. If it seizes, there's a metal bar that will break and allow coolant to flow unrestricted. In the aftermarket model, it may seize closed, which will overheat your engine and warp your nice aluminum heads. At a least a $1000 repair bill just to save $5 on a thermostat. That's coming from experience the expensive way. If this isn't an older car that you're restoring (something with cast iron heads), the thermostat is a critical component. I would pay the extra couple of dollars and buy from the dealership even if the temperature ratings are the same.