You should re-read what I copied, then. The FSM has a single specification. That's it, that's all. One. The rest of the parts for the other systems of the vehicle in there are listed in a similar manner. If they thought the dealer mechanics were going to second guess every single bloody specification or if an incorrect part carried a risk of injury, maybe they'd put "only", but instead, it is assumed that the service technician will use what the engineers put, so that the vehicle will function as designed, and within parameters such that the manufacturer can warrant it's performance. If you were supposed to use anything else, it would be listed as an acceptable part. However there is but a single part number listed.

I don't see where this "210" business came from.

 

I've read it numerous times.......my '98 FSM says the same thing as your '99. Neither your '99 or my '98 FSM says "u must use a 195 stat". Neither FSM says "u must use 215/75/15 size tires", neither FSM says "the motor must operate at 210 to be normal operating temp.....nor does either FSM say "the exhaust must be 2.25", or the throttle body must be......, or the intake must be........, and on, and on, and on. Lot's of folks drop to the next lower rated t-stat with no ill effects. For 3 1/2 years our XJ has run great with a 180 stat.......and the FSM does not say "do not use a 180 stat".

 

it's funny how much ppl will argue over a 15* difference in coolant temp.

 

lol you guys can run whatever stat you want. Factory is 195, that's it, that's all.

I guess you get a point on semantics, djb383, but I don't see how it matters. It's not like a non-factory spec stat is an upgrade

 

Since the 180 Stant SuperStat says "Made in USA" and the Mopar stat says "Hecho en Mexico", I look at it as a lower temp upgrade.

 

I worked in the development lab at standard-Thompson. That's the factory that made stant.
Factory is closed for about 10 years.
Any guesses where they are made now?

 

You southerners can keep your low temp stats, I'll keep my hot heat

 

I bought a Stant Superstat (180) 4 mos ago for a Buick 3.8L......the stat is stamped "USA" and the box says "Made in USA". A 180 will make us sweat in eithwr the XJ or the LeSabre.

 

Even when it's -40F?

 

Something tells me there won't be much difference in heater performance (between a 180 vs 195) at -40 ambient. Mid-teens are common here and a 180 works just fine at those temps.