2011 Aveo overheating, blowing out coolant

[MuteMarmoset]

One problem with using water is that the ratio gets skewed, and your vehicle no longer has the proper cold weather protection. So at this point you should buy a bottle of concentrated coolant and do the next topping off with just that alone (any of the 'lifetime all-vehicle' coolants is fine). That hopefully might restore the coolant/water ratio back to where it should be, but you MUST absolutely test the coolant with the proper tool before Winter sets in. The other problem with tap water is that it may contain minerals which are harmful to the metal cooling components. For that reason it's important to buy and use distilled water, instead of taking it from a tap.

AFA purging the air, I don't know if the second gen Aveo is different than my vehicles, but in any case this procedure should work fine. With the vehicle cold, remove the coolant overflow cap and then idle the vehicle for an extended period of time, with the heater and blower on the highest setting. Bump up the revs to 2-3K for short periods of time, in order to get it heated up faster. While it's idling, watch the overflow tank and top off with the concentrate as necessary, filling somewhere between max and min. Then once the level is no longer dropping, put the cap back on and give it 5 more minutes of idling to let the system fully pressurize. Then shut it off and wait for it to completely cool down in order to check the overflow level again. Top off as necessary, and then get it heated up again, this time with the cap left in place. Repeat that sequence until the level no longer drops.

I am on well water that would have gone through a filter/softener. But I will remember that should I need it again.

And about the burping: I watched some videos, and they were all big on wedging a funnel into the overflow tank opening. I take it that's not necessary if you just use the funnel when topping up and pour carefully? The videos also recommended squeezing the radiator hoses as it idles, to both get out air and to see if the two hoses were at the same temperature. They also filled the reservoir to the top, which I thought you weren't supposed to do.

How long is "an extended period of idling"?

[avguy]

I am on well water that would have gone through a filter/softener. But I will remember that should I need it again.

And about the burping: I watched some videos, and they were all big on wedging a funnel into the overflow tank opening. I take it that's not necessary if you just use the funnel when topping up and pour carefully? The videos also recommended squeezing the radiator hoses as it idles, to both get out air and to see if the two hoses were at the same temperature. They also filled the reservoir to the top, which I thought you weren't supposed to do.

How long is "an extended period of idling"?

I've never done the funnel wedge thing, but I also wouldn't knock something like this that I've never tried myself. Squeezing the hoses is fine, but I never saw bubbles from the tank when doing that, and gave up on it quite a while back. No reason to fill the tank all the way - just monitor and continue topping off to no more than the max line.

AFA how long to idle, it's basically just until the t-stat opens, allowing coolant to circulate throughout the entire system for a few minutes. So if you don't have an OBD realtime reader to tell you what the coolant temp is, then checking to see if both rad hoses are hot is a good alternative way to know that coolant is moving through the system.

[MuteMarmoset]

I idled it for 45 min. during which I added coolant twice. It did not take a great deal so if it's now driveable, then I will need to get it tested/or emptied and filled with all anti freeze for winter.

The engine ran smoothly the entire time, and the gauge did not tick above half, even when revved. After I replaced the cap, I ran it for a further ten minutes and it was fine. The hoses heated up as they should and there was no boiling. There was no bubbling up when I squeezed the hoses.

I am going to try and drive it to town tomorrow (25 mi). I will put a jug of water in the car in case. I did have it out for a short drive with a hill this morning, 15 miles round trip, and had no issues. But there has been a check engine light on since the first boil over two weeks ago, and I need someone to run a diagnostic tool on that.

[avguy]

… I will need to get it tested/or emptied and filled with all anti freeze for winter. ….

That's something you could DIY for less than a shop would charge, and it wouldn't be all that much work either. Just buy a tester like one below, along with an inexpensive fluid pump, and find out what the current coolant protection is. Then, assuming it needs to be improved, pump out the overflow tank contents. Then refill the tank with concentrated coolant, run for a day or so to fully remix the system, then test the coolant again. Just continue doing that until the protection is back to where it needs to be - probably not more than 2-3 reps would be needed to get it back to 50-50.


https://www.amazon.com/Performance-T...9611380&sr=8-4

[MuteMarmoset]

I will certainly do that once the dust settles.

I drove the car to town today. After burping the system and putting in coolant, it seemed to be running really well. No trouble getting there, then I stopped to drop something off. When I started again it overheated in less than 3/4 of a mile. I called the mechanic I was heading for anyway, and he told me to let it cool for a half hour. I opened the hood and it was so hot I could barely touch the support rod.

After a half hour, it started up again fine, and I drove to the garage, which was perhaps 4 miles away. It would be my luck that his diagnostic tool was acting up, but the code for the check engine light did indicate a cooling problem. He opened the hood to listen to it and we stood there talking about what had been done so far. That's when we could both hear a change in the running sound. He stuck his hand inside the front and found the cooling fan was not working.

I'm not technical enough to explain the entire process but he used a little plug in device that would relay around the fan to see if it was actually functional, and it was. Then he got under the car and what he found, was that the contacts for the fan were corroded and covered in gunk. He said the reason that the acting up was so spotty, was that out on the highway it's a smooth run and continuous working, but when you stop and start like running errands in town, it was more likely to stick and stop working. Then he asked if the AC was working well.

Back in June after the first time it boiled over, I discovered my AC wasn't working and it turned out I needed freon. Both my own mechanic and the one where I took it for that work told me that the AC had nothing to do with the overheating, which was wrong. If the fan is not working right, you're not going to get the cool air in, nor cool air over the engine. And there were times that it seemed not to be putting out enough cold air and I put it down to our unusually hot summer.

Bottom line (for now): He cleaned the contacts off and everything looked good. I was able to drive around town on errands, and then the 25 miles home with no issues. He said it should be fine, but it it happens again, I would likely need a new cooling fan.