# 2011 Cruze coolant circulation



## apcnc (Oct 7, 2013)

Hello, I am working on my daughters 2011 Chevy Cruze. It seems the thermostat will not open. She recently purchased the vehicle from a local dealership that apparently tried to cover some major issues and pawn it off. The vehicle ran hot and warped the head. All four cylinders had water inside. They had added alot of some sealer which had been leaking creating a trail down the engine. It also seems that it had an electrolysis issue as well bad battery corroded cable and the list goes on. To get to the point, I found the head to be warped .001" from the center to both ends and 0.005" between the cylinders so had the head resurfaced and installed a new gasket. Installed a new battery cleaned the cables but I'm still showing some voltage in the coolant after flushing the system. Fluctuating .3-.6 volts. The water neck was dissolved I'm thinking from electolysis, never seen one this bad. There are parts of the neck or outlet that are just gone and the whole thing was falling apart as was the plastic in the water pump. New pump neck etc. The thermostat actually looked new so I stayed with the existing thermostat. Running the engine initially the fan would come on but the thermostat would not open the temp would climb past 220-230 with no flow except in the heater core. The heater works and will actually cool the engine down. Without the heater on the temp will climb past 230, boil and overflow. I have 50/50 mix.. test showing boiling point of 265 F. One time was able to get the thermostat to open holding 2000-2500 RPMs as stated in the service manual. From that point it cycled and regulated between 205-215. The following day after cooling off the thermostat again will not open. I installed a new thermostat with no change whatsoever. The thermostat in my opinion is located in the wrong place. Checking the temp the engine will heat up and overheat while the thermostat is still at 150 F. The service manual show a sensor in the thermostat while Ive read elsewhere that this a heater to open the the thermostat with the ECM. It makes sense to have the heater since heat rises and the the thermostat is in a bad location to work properly. Trying to get some decent prints from the Alldata system but cannot seem to find any electrical with any substance to it. I'm thinking its an electrical issue if it is in fact controlled by the ECM. and I don't know how I could have any air pockets left. I pulled the hose off the the thermostat to to see if the coolant was there. Full to the plug in the radiator etc.

If anyone has ran into this please share. Thanks


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## obermd (Mar 3, 2012)

This sounds like the car was run without coolant. The aluminum heads on the Cruze don't handle overheating well. The car wasn't properly repaired after the engine overheated.


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## ChevyGuy (Dec 13, 2014)

Yes, that's a heater connected to the thermostat. The design allows the computer to control the operating temperature while still having a fail safe if things should get hot. I'm thinking you may have a issue that's preventing the coolant from circulating properly.


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## apcnc (Oct 7, 2013)

obermd said:


> This sounds like the car was run without coolant. The aluminum heads on the Cruze don't handle overheating well. The car wasn't properly repaired after the engine overheated.


???? I do not follow, any specifics? Are you saying I should have replaced the head, the engine? What exactly does this mean? Where is the thermostat related to this? The water jackets are sealed as well as the combustion chamber the system has been flushed. etc. I believe I have some other grounding issues not addressed yet.

Thanks


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## apcnc (Oct 7, 2013)

ChevyGuy said:


> Yes, that's a heater connected to the thermostat. The design allows the computer to control the operating temperature while still having a fail safe if things should get hot. I'm thinking you may have a issue that's preventing the coolant from circulating properly.


I don't think it has much of a failsafe until its too late. The engine can overheat before the excess heat an travel Down to the thermostat. This is an enormous blunder. Coolant is not circulating through the radiator. It will through the head and heater core. Just not past the thermostat. I can read 225 from the ECM. Same at the outlet and up to 235-240 in the center of the head. and 140 at the thermostat.


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## apcnc (Oct 7, 2013)

Also the fan doesn't seem to want to come on. I will turn on the heater to cool the engine after reaching 224-5 F to give it time to start cooling down. It needs something to allow the thermostat to open. If it is the heater as Ive read and you are saying, I believe its an electrical issue or bad ECM. It is erratic and have actually received a U0100 lost Canbus data. Hopefully a power or ground issue.


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## jblackburn (Apr 14, 2012)

Does the engine fan run on low speed or just high? (Try switching on A/C). That will activate low or medium speed. 

Several Cruzes here have had the engine fans or relays go bad on lower speeds. I can't recall if 230 activates high speed, but I believe it does - I've heard mine scream after coming back to the car after parked a couple minutes where it's had a chance to heat soak.


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## apcnc (Oct 7, 2013)

Fan hasn't been coming on unless the ac is switched on. And it's on low. Coolant is circulating now. Found some ground cable issues bad connections with voltage drop. But I believe there are more and canbus issues. Also added more coolant above the fill line. The cap seems to seal faster and hold pressure. I drove it and it's holding 221-225 mostly. Jumped to 230 a couple times. Canbus data loss popped up again once. All gauges drop out when this happens and request service for everything.


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## Merc6 (Jun 8, 2013)

apcnc said:


> Fan hasn't been coming on unless the ac is switched on. And it's on low. Coolant is circulating now. Found some ground cable issues bad connections with voltage drop. But I believe there are more and canbus issues. Also added more coolant above the fill line. The cap seems to seal faster and hold pressure. I drove it and it's holding 221-225 mostly. Jumped to 230 a couple times. Canbus data loss popped up again once. All gauges drop out when this happens and request service for everything.


That sounds like you need the ground cable swapped out. 2011-15 model year had bad ground cables.


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## apcnc (Oct 7, 2013)

Merc6 said:


> That sounds like you need the ground cable swapped out. 2011-15 model year had bad ground cables.


 Is this all grounds? Did they have bad wire, connectors, contaminants causing corrosion? Do they sell all the grounds together as an assembly? If there is a website or page showing the individual ground/s with issues that would definitely help. I have the main ground lead from the battery making much better connection but still have slight drop under load. It has to have a bad connection to the battery clamp or opposite lug. I plan to replace the ends asap. That may be all but if there are others, the car has 20 grounds to check under load. As of yet The schematics I have do not tell what most connect to. If you know of any documentation that sure beats tracing it... Thanks


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## jblackburn (Apr 14, 2012)

apcnc said:


> Is this all grounds? Did they have bad wire, connectors, contaminants causing corrosion? Do they sell all the grounds together as an assembly? If there is a website or page showing the individual ground/s with issues that would definitely help. I have the main ground lead from the battery making much better connection but still have slight drop under load. It has to have a bad connection to the battery clamp or opposite lug. I plan to replace the ends asap. That may be all but if there are others, the car has 20 grounds to check under load. As of yet The schematics I have do not tell what most connect to. If you know of any documentation that sure beats tracing it... Thanks


The main negative battery cable itself is a common issue with these cars and can cause all sorts of weird electrical issues.


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## apcnc (Oct 7, 2013)

There is no substitute for quality wire and connectors. Especially in a dirty environment. Once you have corrosion on stranded cable you may as well replace it or remove the bad part if possible. Its hard to say on this one because it had other negligent issues when she purchased the vehicle like a 6 yo battery with the level 1/2' below the plates leaking and corrosion.


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## obermd (Mar 3, 2012)

http://www.cruzetalk.com/forum/25-g...al-coverage-14311-negative-battery-cable.html. This is good for 10 years or 120,000 miles and is a free replacement. Get this done before wasting any time on debugging your canbus issues.


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## Merc6 (Jun 8, 2013)

obermd said:


> http://www.cruzetalk.com/forum/25-g...al-coverage-14311-negative-battery-cable.html. This is good for 10 years or 120,000 miles and is a free replacement. Get this done before wasting any time on debugging your canbus issues.


This. Sounds like you have a slew of issues (that may not be cable related) but some could be erroneous stemming from this issue. I had so many parts swapped out on my car to include 3 dead ignition coil packs, fried brake booster pumps and a whole under hood fuse box before this cable was replaced. It's a free part, I totally understand if you are skeptical of dealerships, sad that has to be that way but not everyone can be trusted these days.


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## apcnc (Oct 7, 2013)

I'm not necessarily opposed to that. I am skeptical of all until I have some experience with the particular shop or dealership. What I am opposed to is part swapping as a diagnostic tool. I want to find the source, many times something may work temporarily but you may only fix a symptom of the underlying issue. In this particular situation I've seen the cable at fault. If repaired I would want to hear that it was tested under load and the findings. The dealership where she purchased the vehicle was not a GM dealership. But a GM dealership is hit or miss also. Many of service techs show you how much they know just by talking. I'm very astonished sometimes. Unfortunately to the average person I suppose it hard to tell. Either way most can spot a part swapper but its usually after the fact.


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## carbon02 (Feb 25, 2011)

There is one member on the forum who wrote the How-To on the water pump removal that had an over heat condition that caused part of the water pump impeller to come off and lodged around the inside of the housing. Requiring a second water pump repair. If I remember he was rebuilding a salvaged title vehicle, so there was a lot of work done on that side of the engine. 

Original pumps had thermoplastic water pump impellers. Electroloysis of coolant maybe hard to track, but starting around the thermostat housing which contains the electrical resistor heater is a good start. 

If air pockets are trapped in that lower hose and a user goes to drive it, the ECM commands the heater element, and if it's not in liquid coolant it's going to fry. Will the ECM know that the heating element isn't cooling and shut it down before failure. I don't know. 

This 1.4L has coolant going through the block, the oil cooler, radiator, radiator hoses, and heater core. I'd rent a radiator pressure tester, and test the system. Better yet check it under vacuum with a U-View coolant vacuum fill tool, if you have access to one. Any air pockets in this system are going to cause problems. Given this engine has been disassembled to the point of head removal, there's a lot of passages that were exposed to air.


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## apcnc (Oct 7, 2013)

This pump did not have a plastic impeller only a plastic plate behind that was destroyed. Same with the new one. It had most likely been replaced as was the thermostat. It appeared new. 
Its working for now though after repairing grounds. Still have some lugs and or cable to replace though. Before it circulated fine one time until it cooled down. Then stopped circulating again throught the radiator. It has circulated through the heater core the whole time. 
It would only make sense to monitor the rate of current flow and temp from sensor along with a PWM output which should throw an error instead of destroying heater. But the print shows only a switch from the ECM. Power from KR75. There may be more to the circuit or not. It should at least be timed.


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## apcnc (Oct 7, 2013)

Here's some pics of the water neck if anyone is curious.


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## ChevyGuy (Dec 13, 2014)

apcnc said:


> It would only make sense to monitor the rate of current flow and temp from sensor along with a PWM output which should throw an error instead of destroying heater.


Well, I don't think there's any temperature sensor on the thermostat. If the heater does open up, it will set a code.


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## ChevyGuy (Dec 13, 2014)

apcnc said:


> Here's some pics of the water neck if anyone is curious.
> View attachment 207922
> 
> View attachment 207930
> View attachment 207938


I wonder what the prior owner used as coolant? Perhaps some of that "instant leak fix" stuff?

If it was me, I'd be thinking about doing some more flushing to get all of that out of there. A simple drain usually doesn't get it all.


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## apcnc (Oct 7, 2013)

ChevyGuy said:


> Well, I don't think there's any temperature sensor on the thermostat. If the heater does open up, it will set a code.


There isn't. But should see a rise in the one in the radiator. If not the it isn't opening. Once open the flow should carry enough heat to keep it open until the engine temp drops.


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## apcnc (Oct 7, 2013)

There was some coolant in it. But only about almost 3/4 of a gallon left. After settling in a jug its orange again... on top. about 3-4" of sludge under it. They just added some sort of sealer plus the remnants of the disintegrated plastic. They told her it belonged to their service tech. I ask them if he knows anything about what he's doing. I was furious still somewhat actually. They said he was the best there is.... He wasn't even that good with the pressure washer. He left a lot of tale tale signs an stalactites hang from his sealer running down and dripping. 

I did flush it several times also. I have many jugs of sludge and gray water!


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## jblackburn (Apr 14, 2012)

Dex cool + exposure to air/cavitation from the pump will leave that kind of build up and a pretty good amount of sludge.


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## Shroomie (Jan 16, 2017)

for future readers that have thermostat/electrical issues. check the wiring to the heating element at the connector and the pins at the ECM. the car shouldn't reach over 226.

I've monitored my ecu desired temps along with the ect/rct sensor and thermostat heating element operations. most of the time my ect desired temp was 221 or 203.

things I've noticed.. the cooling fan isn't temperature based. if the ect desires temp at 221.. the cooling fan won't kick on until closer to 228... if desired temp is 203 the fan will kick on at 210.

if you notice your temp is constantly between 221-230 and your engine fan is on...especially while driving (in the winter)...your cooling system is compromised.. you either have bad flow or thermostat issues. the car is running off of the wax pellet that begins to open at 221 and opens more the hotter it gets.

the only thing stoping coolant from corroding the wires is an Oring in plastic. it causes resistance and keeps the ecu from effectively manipulating the thermostat.

this doesn't mean you're overheating as the thermostat still works but you may notice your temps climb to 230 during loads or idle and the fan is on and doesn't shut off..

you'll see your coolant temp go from 230 to 217 and the fan remains on and then repeats the cycle. this is the wax pellet operation and not the desired ecu temp.


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## Shroomie (Jan 16, 2017)

most ppl don't notice this or are aware.

I've seen some members get corrosion from the thermostat all the way to the ecu causing 12v issues with the coil pack/misfires and grounding issues/blowing coil packs. its like the coolant wicks up the wiring. pretty wild.

the heating element is not an on/off switch command. the ecu regulates the voltage.. full 12v is wide open... most of the time I've seen it commanding half of that power to regulate the temperature rather than full open and have big swings in temperature


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