08 Chevy Equinox overheating problems, "ENGINE HOT/ A/C OFF"
 

I have a 2008 Chevy Equinox AWD, 3.4 V6

The weekend before 4th of July my car started having overheating problems it would be fine and then all of a sudden it was overheating and warning alarms were going off and giving me a warning on the dash saying "ENGINE HOT A/C TURNED OFF" and "ENGINE HOT IDLE ENGINE". The first time I got this warning I was waiting in the drive-thru. The second time it happened I was backing into my driveway after driving home from the store which is only 2 maybe 3 miles away. When I stopped and turned off the engine it dumped antifreeze out the overflow, and you could see a trail on the driveway from me backing up. On an important side note my thermostat gauge on my dash hadn't been working correctly for a while; it worked here and there. Sometimes the gauge would read like normal, sometimes it wouldn't read or move up at all and one time it went all the way to the top past the red, but the car wasnt overheating. Also I had been getting a "TRACTION CONTROL OFF/SERVICE STABILITRAK/ STABILTRAK OFF" warning as well.

At this point we changed the thermostat and flushed the system. Still had the same issue. We then changed the coolant temp sensor. Again still the same issue and warnings. Then the serpentine belt was replaced and then the water pump. Still not fixed, all issues are still happening.

So we borrowed a scan tool from a friend to read the codes on my car and it gave 6 codes:

-P0403 Exhaust Gas Recirculation Circuit Malfunction
-P0404 Exhaust Gas Recirculation Circuit Range/Performance
-P0405 EGR Sensor A Circuit Low
-P0442 Evaporative Emission Control System Leak Detected (small leak)
-P0455 Evap System Large Leak Detected
-P0469 Purge Flow Sensor Circuit Intermittent

So at this point we ordered the EGR valve as that needed replaced and has seemed to fix the issue on the first 3 codes P0403, P0404, and P0405; I also no longer get the "TRACTION CONTROL OFF/SERVICE STABILITRAK/ STABILTRAK OFF" warning going off and it previously would usually go off within a block or two. But we are still having the overheating issue, we have not driven it to the point to get the overheating warning to go off again though because we don't want to continue to overheat the engine. Although we can let the car run in the driveway for an hour and it won't overheat, we did this several times while trying to bleed all of the air out of the cooling system, and have been able to since the issue started. However if you take it out for a drive you can't really go further than 5 miles without it overheating and getting the alarms and warning on the dash.

We have thought about the possibility of a head gasket the car isn't really showing any signs of it being a head gasket, no white smoke or anything out the tail pipe and the oil is fine, not milky or anything. But could still be a possibility.

Also I'm pretty sure the P0442 and P0455 and possibly the P0469 are going to be covered on a recall on it, I have a letter for it cause my car was a "may be affected by it" list. Cause it had seemed like I had been smelling some gas, so with those codes and the letter I think that's covered and most likely not affecting the overheating issue.

So the following is what we have done:
-Replaced Thermostat
-Flushed cooling system
-Replaced Coolant temperature sensor
-Replaced Serpentine belt
-Replaced Water pump
-Replaced EGR vavle (this fixed the service stabilitrak/ traction control warning)

Also both of my fans are working and kick on. The first one will come on when it hits the halfway mark and then when it starts to to get really hot, the second fan kicks on, so pretty sure I don't have a fan issue.

I'm not really sure where to look and what to check next, PLEASE HELP!

Thank you!

Replace the coolant lid. It's a simple part, but it keeps the cooling system under pressure. Coolant boils at a much lower temperature than it should when it isn't under pressure. This causes steam & hotspots to form in your cooling system. If a big steam pocket forms around your water pump, coolant will stop circulating, which makes things worse.

The coolant temp sensor will indicate erratic temps as a result of this. Liquid conducts heat much better than steam with regard to the brass tip on the coolant temp sensor.

That makes perfect sense. I had considered that, but then I thought surely that's not what is causing all of this. I will go get a new one tomorrow and try that. Thank you for your reply and the explanation on why, that really helps!

Well replacing the lid didn't fix it. Started overheating and getting the same warning again.

Did you bleed it again after replacing the cap? If not try this first.

If the old coolant was left in there too long, your radiator maybe gunked/plugged up and need to be replaced.

It is also possible that you have a bad head gasket. This guy pressure tested the cooling system at 20 PSI to find it.

We did bleed it again, but possibly not enough with how these engines tend to hold air. We are going to work on bleeding it again and see if we get anymore air.
We had thought the radiator might be clogged also, but haven't went that route yet. Thank you for that video cause that makes me wonder about the head gasket again. If bleeding it more doesn't fix it, I believe we will take it and have it tested.
You've been a great help! Thank you, and I'll update and we try these next few things.

Hi
 

I have the same issue with my truck was there a solution to this problem please let me know thank you my phone number Is (send me a PM)

you prob shouldnt post your phone number on a public forum/post.

Same issues
 

Did you ever figure out what the problem was? My son recently purchased an '08 Equinox 3.4 V6. We replaced the radiator, engine temperature control sensor, thermostat, reservoir cap, bled the system after each action. Still having the same issue. We know the EGR needs to be replaced, but trying to tackle the overheating issue first. We tested the water pump, it's good. We are just stumped.

Is the Check Engine light on? If so, what codes are stored?

Have you verified the radiator cooling fans are working?

Lastly, I'm curious to hear how one tests the water pump.