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Cold Radiator Cap After Driving

Jardner27

New Member
Joined
Feb 18, 2020
Messages
4
Location
Ann Arbor, Mi
Hi all. I apologize in advance if I am in the wrong area. I live in southeast Michigan. Our average temp right now is about 30° F. I have a 2014 2 door jeep JK with just under 70k. It was my wifes brand new, but we've got her a newer vehicle and I took the jeep. Anywho, I saw steam coming from under the hood about a week ago. I checked the coolant and saw it was low and thought, "phew, close one". Topped it off. But I noticed the radiator cap was FREEZING cold after driving for 30 minutes. I have never not had heat. Went about a month or so with thinking the heat was slightly not as hot as usual, but with having a soft top and it being cold out, I figured the heat was just making it's way to the outside. I've since changed the thermostat, radiator cap, and burped the cooling system. An hour and a half run time with the cap off to be exact, and at an incline. Upper hose is hot, lower hose is cold, I still have heat, my temp gage is at the center mark where it always is, and my digital gage reads between 203 and 217 while driving. Transmission reads about 170. I have no idea what could be going on. Some suggest needing a coolant flush, some say bad water pump. There are no signs of leaks, whatsoever. After the burp on saturday, I test drove it and had parked it on a fresh pile of snow after the drive, and had 0 drops or evidence of leaking coolant. Any thoughts help, thank you! Sorry for the long post.
 

Chris

Administrator
Staff Member
Joined
Sep 28, 2015
Messages
32,247
Location
Florence, AZ
Two things:
  1. Did you use a factory thermostat, not a low temp one?
  2. What kind of coolant did you use?
 

Oscar-Mike

JK Enthusiast
Joined
Nov 26, 2019
Messages
596
Location
Off Grid
Well I never touch my rad cap if thought it's hot.
Just wondering if the fluid is flowing through.
 
Last edited:

Chris

Administrator
Staff Member
Joined
Sep 28, 2015
Messages
32,247
Location
Florence, AZ
I'm just trying to make sure the thermostat isn't a low temp unit. If it is and you're in a cold climate, your thermostat is basically never opening, hence the reason it's so cold.

I would look into that thermostat you installed and see what temperature it is.
 
OP
J

Jardner27

New Member
Joined
Feb 18, 2020
Messages
4
Location
Ann Arbor, Mi
Oscar-Mike, the cap is definitley cold to the touch. It does warm up after I park the jeep but never gets to it's hottest then either. And Chris, if my new stat is low temp, I'm still stuck wondering what happened before changing the stat. I am so confused and never heard of anything like this. Lol
 

Oscar-Mike

JK Enthusiast
Joined
Nov 26, 2019
Messages
596
Location
Off Grid
This is the basic principle of a cooling/heating system.
With this diagram thermostat dictates the pump on how hot/cold he needs the engine to be. So you have to start with the thermostat.

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