[4pfrt]

My charger r/t is giving coolant problems. I changed the thermostat still no resolution. My heat blows cold majority of the time but sometimes goes hot then back to cold. I have enough coolant. The radiator fan works. The coolant is just not circulating through. The car doesn’t really overheat but it runs hot and gets hot quickly and when i park the coolant bubbles. What could it be? I think water pump or heator core but the coolant circulates just sometimes, so I think the water pump is fine but idk

 

[georgiapi]

Check the water pump by removing the belt and spinning the pulley for feel and noise and side to side for wobble.

 

[4pfrt]

Wouldn’t there be steam or a whining noise from the water pump if it was bad? Would a bad thermostat cause the heat malfunctions?

 

[krautmaster]

You may have a cracked overflow tank... if it has a hairline crack it won't hold pressure and will cause some of the symptoms you describe, especially the coolant bubbling. You can have the system pressure tested to see if it is just a bad cap or a cracked tank (I had to replace three on my old Chrysler 300M and one on my 2013 Charger). A sticking thermostat is also a possibility.

 

[djalbin]

If you're not losing coolant the problem may be a combination of air in the coolant system and a pressure cap that's not holding pressure.
.

 

[4pfrt]

Yeah im not losing coolant, and it will bubble and the whole resivor tank would fill up to the top all of a sudden. The heated seats also stopped working. Everything else works radiator fan, thermostat is new, water pump is a year and a half old. I’m just not sure what it could be causing it not to flow properly. I will check the lines to the reservoir tomorrow maybe there clogged.

 

[N8ECH]

First off, my vote would be air pockets in the system.
What year, and how many miles on your R/T?

Don

 

[4pfrt]

2012 Rt. With 130k miles had it for about 2 years since it was at 80k it’s well maintained. The overheating started after my last road trip I let the car idle for a while I stopped and took a nap. When I woke I saw the temperature reached a very high temperature it never reached before. I started to drive and everything went back to normal. Later on that day my heat started to malfunction. It had a thermostat code so I changed the thermostat. But when I put coolant in it barely flows into the thermostat which is causing me to think its the water pump working only sometimes. I recently replaced the water pump a year ago so I don’t think its that. The heat blows cold but warm occasionally. It get hot after about 10 minutes of warming up in park or 2 minutes of driving. I tried the bleeding method where you pour coolant into the resivor until it leaks out of the bleeder spot but the coolant didn’t go anywhere. Maybe the coolant just need a proper bleed.

 

[N8ECH]

If it's overheating at low speeds/idle, it sounds like your radiator cooling fan is not working properly, if at all. When you turn the A/C on, does the fan come on right away?
When you bled the system after the T stat change, did you have the engine running, and heater on high? It also helps to run the engine rpms up to 1.5-2K several times during the bleeding process, to move the air up and out.

Don

 

[4pfrt]

If it's overheating at low speeds/idle, it sounds like your radiator cooling fan is not working properly, if at all. When you turn the A/C on, does the fan come on right away?
When you bled the system after the T stat change, did you have the engine running, and heater on high? It also helps to run the engine rpms up to 1.5-2K several times during the bleeding process, to move the air up and out.

Don

Yeah the radiator fan works, and thats whats stoping it from overheating but it does run hot fast when you start driving. I bled the system but I am not sure if I even bled it right. How do you? I’ve seen the method where you run the car and just keep adding coolant until the radiator fan comes on 2 times, and i seen the method where you unscrew the bleed spot on the car and pour coolant until it leaks out of the bleed spot.

 

[79jasper]

Just to throw it out there, the overheating/Coolant has nothing to do with your heated Seats.
You definitely still have air in the system if the heat is coming and going.
I like to use the spill free funnel method. Gets the fill point above the engine and heater core. Make sure you have the heater turned on.

Sent from my SM-G988U using Tapatalk

 

[djalbin]

the overheating/Coolant has nothing to do with your heated Seats.

Plug a scanner that can read all modules/codes into the car's OBD2 port and see if any codes are logged. Codes posted by the HSM (heated seat module) are Bxxxx body codes.
.

 

[4pfrt]

I bled the system again and the heat and everything started to work fine, but as I was driving it started to go a little cold for a second again. I think I need to bleed it one more time to full get all of the bubbles out, or maybe there could be a crack or leak somewhere causing it to get more bubbles? When I bled it this time I didn’t have enough coolant to fill all the way to the top but it seemed to work.

 

[N8ECH]

Get the coolant properly topped off, and you will likely be good to go.
Cooling systems and air, don't get long very well.

Don

 

[4pfrt]

so the next day I went out and the car heat was cold again and took a long time to get hot. It got hot for a while but once again as I drove it started to get cold again. I’m not sure what it could be as it had coolant in it and was just running pretty
Much hot and fine the night before.

 

[79jasper]

So the temp will come up if you sit there idling, but drops when you drive?
If so, Thermostat is stuck open.

Sent from my SM-G988U using Tapatalk

 

[jdud620]

You may have a cracked overflow tank... if it has a hairline crack it won't hold pressure and will cause some of the symptoms you describe, especially the coolant bubbling. You can have the system pressure tested to see if it is just a bad cap or a cracked tank (I had to replace three on my old Chrysler 300M and one on my 2013 Charger). A sticking thermostat is also a possibility.
View attachment 302605

Yeah im not losing coolant, and it will bubble and the whole resivor tank would fill up to the top all of a sudden. The heated seats also stopped working. Everything else works radiator fan, thermostat is new, water pump is a year and a half old. I’m just not sure what it could be causing it not to flow properly. I will check the lines to the reservoir tomorrow maybe there clogged.

This is exactly how Three Mile Island happened. A high point system leak occurred (Pressurizer relief was open, or in this case the cracked reservoir) which allowed boiling in the core (or engine block here). The steam void in the core pushed the coolant to the resevoir but the core was then not being cooled.

Has your car been fixed? What was the culprit?