[burgandy25]

Good afternoon,
Friday we had our 2013 Volt serviced to get the Coolant heater control module replaced. Every startup hereinafter it's made a gurgling noise that I assume is the coolant. When I was talking to the service advisor less than an hour before the shop closed he made it seam like they were in a rush to get the Volt back together to get it out the door before they closed, and this makes me think they didn't go through the proper procedure of filling the system with tool: GE-47716 that pressurizes the system to burp the system.

The noise we hear I think it's an air pocket that is not allowing proper flow. Again I think this because now the heat won't get past warm, on full blast in comfort mode. The old heater control module when it would work would get very hot, not so much since Friday. This makes me think there is an air pocket. What do you all think?

I will be calling Monday morning to the advisor I worked with to try and see if the tech did follow this, I'm guessing I'll get the run around but the last thing I want to do is get a whole coolant change that will force them to use that GE-47716 tool.

 

[somms]

FWIW: Post CHCM replacement on my Gen1 a couple of years ago, I never experienced any gurgling issues so I would say this is not normal.

Was yours replaced under warranty work?

 

[Fyodor]

Your diagnosis seems to be the most likely case. I'd have them purge it properly, which should have been part of, and costed into the original service.

 

[colchiro]

You have air in your coolant lines that needs to be purged. Hopefully you don't have a leak letting in air.

 

[WopOnTour]

Good afternoon,
Friday we had our 2013 Volt serviced to get the Coolant heater control module replaced. Every startup hereinafter it's made a gurgling noise that I assume is the coolant. When I was talking to the service advisor less than an hour before the shop closed he made it seam like they were in a rush to get the Volt back together to get it out the door before they closed, and this makes me think they didn't go through the proper procedure of filling the system with tool: GE-47716 that pressurizes the system to burp the system.

The noise we hear I think it's an air pocket that is not allowing proper flow. Again I think this because now the heat won't get past warm, on full blast in comfort mode. The old heater control module when it would work would get very hot, not so much since Friday. This makes me think there is an air pocket. What do you all think?

I will be calling Monday morning to the advisor I worked with to try and see if the tech did follow this, I'm guessing I'll get the run around but the last thing I want to do is get a whole coolant change that will force them to use that GE-47716 tool.

Yes there may be trapped air. The instructions found in the service manual must be followed exactly to prevent such an occurrence. The tool you referenced is commonly referred to as a "Vac-N-Fill" and actually places the cooling loop under a vacuum. This helps to draw out the air. An air pocket in the coolant heater can cause it to overheat and possibly be damaged.
When doing the heater/engine cooling loop you are instructed to repeatedly complete a sequence (while the Vac-N-Fill is connected throughout) where you must run the electric pump using the scan tool, and alternating with running the engine in order to be able to dislodge any trapped air pockets.
They may need to repeat this process.Have them refer to SI document ID: 2394254

WopOnTour

 

[burgandy25]

Yes there may be trapped air. The instructions found in the service manual must be followed exactly to prevent such an occurrence. The tool you referenced is commonly referred to as a "Vac-N-Fill" and actually places the cooling loop under a vacuum. This helps to draw out the air. An air pocket in the coolant heater can cause it to overheat and possibly be damaged.
When doing the heater/engine cooling loop you are instructed to repeatedly complete a sequence (while the Vac-N-Fill is connected throughout) where you must run the electric pump using the scan tool, and alternating with running the engine in order to be able to dislodge any trapped air pockets.
They may need to repeat this process.Have them refer to SI document ID: 2394254

WopOnTour

Thanks, yes that is the name of the tool. They made it seams like it was a rush job to get it done, so my guess is they didn't do the correct procedure. I just read the procedure and just don't think they did it. Most likely just topped it up. When I call tomorrow I'll question him and ask for the details because all the service invoice says is:
"...Replaced coolant heater control module. Filled coolant system and road tested to verify repairs."

based on that description it seams like they didn't do the whole procedure because they would have detailed it.

 

[burgandy25]

Today we brought the Volt in again to get the air purged out the the vehicle. The service advisor seams to have agreed that they didn't use the "Vac-n-Fill" system on the original service date when they replaced the heater module. It took them about 4 hours from the time we dropped it off to the time we picked it up. When we did get home I opened the hood and sure enough the coolant was a little higher and there was residual coolant around the reservoir so they did do coolant work. So far today we have driven it 3 times since we got it back and the heat feels very warm. It will get tested more later this month into January when it gets really cold here in MI. I'll update again in a week and update if this turns around and starts acting up again.

 

[Barry]

Would you mind letting us know why you had the heater control module replaced, and the cost? My dealer has been using trial and error on my heating issues and says that repair is the next step. I am not eager to pay for more experimentation.

 

[burgandy25]

Why it was replaced: the heater would randomly not work. Sometimes it would get hot like it should then randomly maybe the next trip after stopping to get groceries the heart wouldn't work and just blow cold air. The dealer couldn't replicate the issue because it worked for them but they took me up on my word and read the TSB that's out about this issue, they replaced it and as of yesterday the heat is hot like it should (after doing the correct fill procedure).

It was done under out certified pre owned warranty so it didn't cost me anything. But I've read on this forum that someone got a quote of like $2k to get it done. Sorry man.

 

[Barry]

Ok. Thanks for the details. That is helpful. My heat problem is not major and we have short winters here. Not worth a major expense.

 

[WopOnTour]

Would you mind letting us know why you had the heater control module replaced, and the cost? My dealer has been using trial and error on my heating issues and says that repair is the next step. I am not eager to pay for more experimentation.

I have spent some time making some recommended adjustments to the "No Heat" Diagnostic for the Gen1 Volt, an abridged version of sorts based on the issues we've identified. It begins with a performance test that checks the coolant heater (if fails must be replaced) and then continues on a path assuming the coolant heater checks out OK. If you pass this along to your dealer they might find it useful.

HTH
WOT

 

[dahn42]

I found your post very informational. I recently took my 2014 Volt to my local Chevy dealer to have the heating problem fixed. They said it was the pump and that it would be $600. I had them replace it, but after they did so they said that the pump was indeed bad, but that it went bad because of a bad module and that there was no way for them to have known that before they replaced the pump. Is that accurate? I feel like I paid $600 for nothing since I can't pay the $2000 to replace the module. Thanks so much!

I have spent some time making some recommended adjustments to the "No Heat" Diagnostic for the Gen1 Volt, an abridged version of sorts based on the issues we've identified. It begins with a performance test that checks the coolant heater (if fails must be replaced) and then continues on a path assuming the coolant heater checks out OK. If you pass this along to your dealer they might find it useful.

HTH
WOT

I have spent some time making some recommended adjustments to the "No Heat" Diagnostic for the Gen1 Volt, an abridged version of sorts based on the issues we've identified. It begins with a performance test that checks the coolant heater (if fails must be replaced) and then continues on a path assuming the coolant heater checks out OK. If you pass this along to your dealer they might find it useful.

HTH
WOT