2011 AVEO coolant boiling the overflow cannister

[WHAT HAVE I DONE]

I recently bought a 2011 Aveo with very light front end damage. The radiator was changed and filled with Dex-cool. Cap left off during initial idling to burp the system of any air.

Yesterday the car was steaming under the hood. a quick look showed the coolant to be boiling in the overflow cannister. The temp gauge was only at the 1/2 way mark so not overheating.

I put a pressure pump on the cannister and pumped it to 17psi. I checked it a couple hours later and it was stilla t 17. so no leaks???

No coolant in the oil. no oil in the coolant. Coolant was Prestone 50/50 Dex-cool

Any suggestions what is causing the boiling?

[Thymeclock]

You will need to check the level of fluid, the radiator cap, the thermostat, and whether the cooling fan is working. Any of these things can cause it.

[WHAT HAVE I DONE]

Coolant fan was on, I am going to pick up a new cap and try that.. Thermostat is pretty pricey so I am going to do that last

[2010AveoLT]

Coolant fan was on, I am going to pick up a new cap and try that.. Thermostat is pretty pricey so I am going to do that last

the caps are actually quite cheap at the Dealer at only $12.

[petrified.rabbit]

it could still be an air bubble? although the thermostat, and a head gasket could still be the culprit. Does the radiator get hot when the fans kick on?

[WHAT HAVE I DONE]

temp gauge is only at 1/2 so not overheating if it is correct. Hoses are all hot. Fans kick on when the A/c is turned on, otherwise they were not on. I got a new cap at the dealership, by the time I got done working 12 hrs shift at work it was dark so i topped off the coolant let it run awhile and put the new cap on and called it a night. tomorrow i will run it some more and see if the cap made any difference.

[Thymeclock]

temp gauge is only at 1/2 so not overheating if it is correct. Hoses are all hot. Fans kick on when the A/c is turned on, otherwise they were not on. I got a new cap at the dealership, by the time I got done working 12 hrs shift at work it was dark so i topped off the coolant let it run awhile and put the new cap on and called it a night. tomorrow i will run it some more and see if the cap made any difference.

Fans kick on when the A/c is turned on, otherwise they were not on.

That doesn't sound right. Usually (on most cars) one fan is activated for usual radiator cooling and the second fan only kicks in when the A/C is on. Check the fans and their wiring. Since there was an accident that you mentioned, you might have a bad wire or loose connector.

[WHAT HAVE I DONE]

Fingers crossed...Drove the car around town to get it heated up. checked coolant all looked fine...Drove it 20 miles on the highway at 65mph...checked coolant all looked fine...no bubbling or leakage detected. I'll leave it sit for a bit then do the return trip and see how it looks later. Hard to believe a $10.00 cap might of solved this issue....more to come

[WHAT HAVE I DONE]

RETURN trip went just as well. No bubbling or leakage. Car has sat since approx February. Running good. Happily the reservoir cap resolved the issue

[maxim1157]

you have the exact same issue I'm having right now..I was looking at my cap and it looks like it has a crack 75% around the outside of the cap. I hope this is all that is wrong with mine.