My 2012 charger rt began running hot yesterday. Coolant boiled in the reservoir. Never fully overheated fortunately. Since the reservoir was full I thought the thermostat might have failed and I replaced it. Today while in stop and go traffic it would get to about 3/4 of the way up the gauge and then the temp would return to normal once I'd start moving again. This would happen immediately and I was only driving about 25 miles per hour, so I'm not thinking it would be due to the air cooling the engine. When I returned home I allowed it to idle to see if the coolant would circulate and drop the temp as it did while driving. It didn't and I shut it down. But again the overflow is full. Why? Obviously this is my problem but I'm not sure if Ive got air in the system or if it's a water pump. I don't want to just throw parts at it without knowing what it is. To make matters worse I'm 3 hours away on vacation with limited resources. Any ideas? Thanks.
Stevesauer
You replaced the thermostat so there could be air in the system. Did the radiator cooling fan turn On when you watched the engine idle and the temp reached above normal? The problem could be the reservoir pressure cap. The cooling system will operate at pressures slightly above atmospheric pressure. This results in a higher coolant boiling point. If the pressure cap is not holding pressure the coolant will boil at a lower temperature. This is one failure mode. The other failure mode is when the cap fails to open when there is over-pressure. The cap contains a spring-loaded pressure relief valve. This valve is suppose to open when system pressure reaches the release range of 16-21 psi.
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Steve:
While you are at it, crank the A/C on and see if the radiator fan activates. If not, you have something amiss there also. If the system won't cool properly at 30 mph and faster, you have air in the system and/or another type of flow issue. Are both upper and lower radiator hoses getting hot? When was the last time (if ever) that the system was flushed and new coolant installed?
Don
While you are at it, crank the A/C on and see if the radiator fan activates. If not, you have something amiss there also. If the system won't cool properly at 30 mph and faster, you have air in the system and/or another type of flow issue. Are both upper and lower radiator hoses getting hot? When was the last time (if ever) that the system was flushed and new coolant installed?
Don
Thanks for all the replies. I'll try to address most of the questions asked by those who posted. The fan does come on. In fact that was what alerted me that i was running hot. That thing is loud! In the year and a half I've owned the car, the coolant has not been flushed/changed. The first time the coolant boiled on me, only the upper hose was hot. I think that's all of the questions raised by others.
I'm planning to start with a change/flush, changing the reservoir cap and bleeding the system of air. I added about a third gallon of coolant yesterday, as it seemed a little below the cold full line. Today I drove 3 hours home from the beach, sat in traffic a bit and it never went above normal temp. I even let it idle in the driveway for 20 minutes when I got home. Fan cycled on and off as it should. It seems, at the moment, fine. But I'm not entirely sure why.
I'm planning to start with a change/flush, changing the reservoir cap and bleeding the system of air. I added about a third gallon of coolant yesterday, as it seemed a little below the cold full line. Today I drove 3 hours home from the beach, sat in traffic a bit and it never went above normal temp. I even let it idle in the driveway for 20 minutes when I got home. Fan cycled on and off as it should. It seems, at the moment, fine. But I'm not entirely sure why.
I just replaced my coolant tank the other day, turns out the lower portion of the tank had a crack that was covered by the pressure clamp/hose back to the heater core, definitely explains some of the issues I had. Might be worth doublechecking the coolant overflow tank while you're doing your flush.
Steve:
It sounds like you might have had some air in there. I am not sure when Dodge went from 5/100 on the coolant to the 10/150 my '14 has, but if yours is the 5 year 100K mile variety, it's due for a change.
Be sure to leave the cap off, and allow the system to warm up all the way while you monitor temp, etc. It helps to run the engine rpms up to 1.5-2K a number of times during that process to help move air up and out. As the level drops, be sure to add enough to bring it to the full hot mark. Have your heater cranked up also to be sure air does not stay there.
Don
It sounds like you might have had some air in there. I am not sure when Dodge went from 5/100 on the coolant to the 10/150 my '14 has, but if yours is the 5 year 100K mile variety, it's due for a change.
Be sure to leave the cap off, and allow the system to warm up all the way while you monitor temp, etc. It helps to run the engine rpms up to 1.5-2K a number of times during that process to help move air up and out. As the level drops, be sure to add enough to bring it to the full hot mark. Have your heater cranked up also to be sure air does not stay there.
Don
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