Winter running temps

[eaglescout526]

Does anyone else’s MJ stay under 210 during the winter? I run the heat every time I hop in and drive and my emissions test is coming up. Last year I replaced my t-stat due to it being lazy and this winter I’ve been noticing what seems like the same symptoms of the t-stat being lazy. The only things I can think of is that I’m running a heavy duty OEM radiator and not running the AC. Is this normal for anyone else besides my 2.5L friends? 
 

The winter of 2020 I ran the AC all winter to make sure it remained working and I recall seeing 210 constantly. 

[AeroNautical]

My 4.0 has always run slightly below 210, and in the high 100s in the winter. But this is the reading on my dash, if I take an IR gun reading on the head itself, the temperature is slightly higher than my gauge reading, but still lower in the winter. I've replaced the thermostat very recently, within a year, and multiple times over the years, with no changes. As long as its not hot or overly cool, I just don't worry about it anymore. 

[watchamakalit]

39 minutes ago, PFCLeist said:

As long as its not hot or overly cool, I just don't worry about it anymore. 

 

 

[87MJTIM]

Mine is always running cool. I think my thermostat is stuck open. The REM show temperatures from 170* to low 190*s with outside temperatures in the 30-40* F. 

[JMO413]

My REM shows 190 and my gauge is well under 210 but it's been a high of 25 lately.

[gogmorgo]

My ‘91 2.5 runs more or less the same temp as it does in the summer, at least according to the gauge. Last winter even though the temp gauge was reading about the same and coming up to temp about as quickly my heater wasn’t working so great. Because I had an extra thermostat I swapped it for $#!&s, even though my thermostat had been new pretty recently. Before putting it back together I put both thermostats in a pot of water on the stove and the old one opened about 30 seconds before the new one. Heat worked great after it went back together, even though the gauge didn’t read any different. 
The gauge in question however sits far enough shy of centre that I don’t really trust it’s accuracy. It’s only ever climbed past that point if I was pretty low on coolant.

 

All of my other vehicles do run a hair cooler in the winter. Roughly thermostat temperature. But it’s usually between 0 and -20°F here, frequently colder, and I never block my radiator, so there’s that. I’ve never thought much of it. As long as it’s at or above thermostat temp it shouldn’t be an emissions concern, and if they’re running the test inside a heated building it’ll be summer inside anyhow. 

[cruiser54]

Mopar stat? 

[eaglescout526]

Yup. It’s a Mopar one. So it seems to be normal to run a bit under during the winter. 

[89 MJ]

I think that you are probably fine. Mine doesn't even run at 210 in the summer (it does run near there though), but I do have a bigger radiator than stock. The Eagle also sits about 180 since I have been driving it from October-present.

[Parei_doll_ia]

I put mine away for winter, but fall here is roughly equivalent to AZ "winter." ( I grew up in Peoria) I put the CSF rad in over the summer and it dropped the temps from 220-230 to where the e-fan could manage it at 200-210. I set the fan to come on at 205 with my REM. In the fall, the temp stuck right at 198 with no fan unless I stopped and idled. 

 

If you're having problems for emissions, you could probably block off a bit of the radiator with cardboard just to pass the test. You're probably fine though if it's above 195.

[87Warrior]

My 2.5L always cools down in the winter time. I replace the thermostat when the heater isn't able to produce enough heat to heat the cab. 

  

7 hours ago, cruiser54 said:

Mopar stat? 

Within the past couple of weeks I ordered a Mopar t-stat from the dealer and received a MotoRad t-stat (without a Mopar part number stamped on it). Did the dealer pull something sneaky or is a genuine Mopar tstat now only labeled as MotoRad?

[eaglescout526]

5 minutes ago, 87Warrior said:

Within the past couple of weeks I ordered a Mopar t-stat from the dealer and received a MotoRad t-stat (without a Mopar part number stamped on it). Did the dealer pull something sneaky or is a genuine Mopar tstat now only labeled as MotoRad?

No. MotoRad is now the supplier for almost if not all Mopar T-stats so you got a genuine one. Sometimes they stamp a number on them and sometimes they don’t for when they’re short on the Mopar ones and put in a public t-stat. 

[gogmorgo]

In my case I got both my thermostats from Napa. I don’t remember looking at manufacturers whenever I got or installed them, but their current catalogue also lists MotoRad as the manufacturer.