So I've noticed with this horribly cold weather lately that if I'm let's say in a parking lot idling with the recirc on the coolant temp stays around 199° but if it's on foot well or defrost it plummets to 170° - 180°

I'm sure it's something to do with recirc putting more load on the motor or something... maybe?

 

If its not on recirc it is using the coolant to warm up the air from below freezing so the coolant temp drops.
On recirc the difference between the air and coolant temp is a lot less so the coolant temp doesnt drop as much.

 

Defrost and foot well settings turn the compressor on, which in turn.....
turns the cooling FANS on.

 

I've had it down to 170 and keep dropping while driving in town when it was below zero out

 

really? dam with my heat on 2-3 and i idle for any amount of time my temps drop 10-15degree ( Celcius ), and warm as i drive. but its also been a steady -30C AND COLDER here

 

I mean I can have it on face position recirc on it'll be 199° turn off recirc it drops, turn recirc back on and it goes back up...

It's just odd hah

 

Over the last few days (-26 yesterday with the windchill) mine wouldn't idle abover 160 and took an hour to reach 200.

 

Im running 150-165 at idle lately but I'm pretty sure my t-stat is stuck open because it never goes past 185 while driving and it cools down extremely fast once I come to a stop. For instance it dropped 8 degrees from sitting at a light. If you are experiencing anything like this, I'm sure we share the same issue.

 

My car runs warmer during the Winter no matter what. I always have my A/C on aswell to keep the moisture under control inside.