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Discussion Starter · #1 ·
2017 Chevy Volt Premier, 153K miles.
I got the P0401 fault code last week so did the EGR valve cleaning and cleared the code.
This morning the weather was cold at about 18F.
Preconditioned, hopped in and drove in Hold to warm up the engine.
About 25 min into my drive I got an 'engine overheating' and 'pull over' error on the display.
When I pulled onto the shoulder it was steaming antifreeze. The coolant temp was right around 200F.
I let it cool down and then drove back home. But, the last 10 miles were on ICE power.
Check engine light came on and I had to stop due to overheating every ~2 miles.
The coolant went up to 230-240F.
So, the car sits on the driveway with evidence of coolant over the engine compartment.
I thought it might have been the coolant hose I removed from the EGR valve.
But, that was one of the few things that was dry.
I have not investigated in detail yet.
But the coolant leak definitely appears to originate on the passenger-front area of the engine bay.

I did run Torque Pro and got the following codes. Once this happened the engine went from smooth running to definitely rough. So, not surprising I get a knock sensor code.

Any ideas? Logic leads me to point to the EGR Valve cleaning. But, I don't think this is a situation where I reinstalled something incorrectly (not my first rodeo wrenching under a hood). The temp definitely went very high at ~240F but I stopped each time immediately so I feel I was able to limp home without internal damage.

I have the upcoming Thanksgiving weekend to do some wrenching on this car. I am leaning on replacing the EGR Valve (and possibly the cooler too). I am not sure on parts availability at present.

Let me know any other ideas!

Paul.
---------------------------------------
Vehicle VIN: 1G1RB6S51HU103213
Vehicle Manufacturer: Chevrolet
Vehicle Calibration ID: Not present

Current Fault Log
------------------
P0325: Knock Sensor 1 Circuit (Bank 1 or Single Sensor)
P0AC4: Unknown code - More information may be available on the web
P16E0: Unknown code - More information may be available on the web

Pending Fault Log
------------------
P00B7: Unknown code - More information may be available on the web
P0324: Knock Control System Error

Historic Fault Log
------------------
ECU reports no historic faults
Other discovered fault codes
(possibly pending, current or manufacturer specific)
----------------------------------------------------
ECU reports no other fault codes logged

End of report.
 

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Others who have had the EGR valve issue in Gen2 have reported that it will blow the fuse (called the non-walk home fuse). The they would see high coolant temperatures. Have you checked the fuse?
 

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I'd definitely check the F3 fuse (non-walk-home). But that can't explain the coolant leak. All you can do, I think, is run the engine with the hood open and see if you can spot the leak.
 

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When the EGR valve fails, the "non walk home" fuse fails. One of the things on that fuse is the electric thermostat for the engine, so the engine will overheat if that fuse is blown.
No idea about the coolant leak. Hopefully, not a warped head or bad head gasket due to overheating.
 

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Discussion Starter · #5 ·
When the EGR valve fails, the "non walk home" fuse fails. One of the things on that fuse is the electric thermostat for the engine, so the engine will overheat if that fuse is blown.
No idea about the coolant leak. Hopefully, not a warped head or bad head gasket due to overheating.
I always thought when the F3 fuse blew the car would not operate. I'll definitely take a look!
 

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Discussion Starter · #7 ·
I have a parallel thread going on FB Chevy Volt Owner group as well......

The F03 fuse wasn't blown. After cleaning the valve I had cleared the P0401 code. Then, I got the new codes shown above when the car overheated and ran very rough. Do you still think this is related to the EGR valve/cooler? Or could this be something else? FYI, while I cannot find the source of the coolant spray pattern under the hood the reservoir tanks still look at normal levels. So, it may simply have been a pressure release. The coolant is more prevalent in the vicinity of the EGR valve though. If the cooling system releases pressure what region under the hood would it most likely be concentrated?
Also, once confirming the F03 fuse was OK I briefly ran the vehicle with the hood open for a brief moment with the EGR connected and then disconnected. In that brief trial, I saw no difference and the car seemed to idle well without any knocking. I guess the next step is to run the engine until the car gets up to temp and see what happens.
 

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coolant release would be from the reservoir pressure cap which likely has a nipple and hose leading away and usually pointed downwards away from the engine.
 

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Discussion Starter · #9 · (Edited)
coolant release would be from the reservoir pressure cap which likely has a nipple and hose leading away and usually pointed downwards away from the engine.
UPDATE: I finally noticed that the gasket did slip while I was reinstalling the EGR valve. It was hanging from one bolt and not seated properly. I removed the valve and reinstalled correctly.... well, almost. One of the bolts has fallen into the abyss. I can't find it. Anyone know the EGR valve mounting bolt size? (UPDATE: I found via a google search it appears to be M8-1.25x33.4mm. I'll see what I can find locally tomorrow).

I ran the engine with the hood up until it was up to full temp. No discharge from reservoir. But, coolant smell and vapors from around the EGR valve. I have a valve, cooler, and gaskets on order. I found someone selling new OEM valves on ebay. I am getting the cooler and gaskets from an online Chevy dealer/parts vendor. I am hoping the valve I receive will be OK. So, this Thanksgiving weekend I will remove the catalytic converter and get it ready for the new parts. Interestingly, the P0401 code has not returned. Engine coolant temp go to 210F. I think the spray occurs when it really gets higher... 220+. I didn't want to go there again! Overall, the engine ran smoothly for the most part. A couple brief stumbles/knocks. The knock sensor fault codes are still present. I am hoping that is a byproduct of the EGR components being faulty.
 

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2017 Chevy Volt Premier, 153K miles.
I got the P0401 fault code last week so did the EGR valve cleaning and cleared the code. Kodi nox
This morning the weather was cold at about 18F.
Preconditioned, hopped in and drove in Hold to warm up the engine.
About 25 min into my drive I got an 'engine overheating' and 'pull over' error on the display.
When I pulled onto the shoulder it was steaming antifreeze. The coolant temp was right around 200F.
I let it cool down and then drove back home. But, the last 10 miles were on ICE power.
Check engine light came on and I had to stop due to overheating every ~2 miles.
The coolant went up to 230-240F.
So, the car sits on the driveway with evidence of coolant over the engine compartment.
I thought it might have been the coolant hose I removed from the EGR valve.
But, that was one of the few things that was dry.
I have not investigated in detail yet.
But the coolant leak definitely appears to originate on the passenger-front area of the engine bay.

I did run Torque Pro and got the following codes. Once this happened the engine went from smooth running to definitely rough. So, not surprising I get a knock sensor code.

Any ideas? Logic leads me to point to the EGR Valve cleaning. But, I don't think this is a situation where I reinstalled something incorrectly (not my first rodeo wrenching under a hood). The temp definitely went very high at ~240F but I stopped each time immediately so I feel I was able to limp home without internal damage.

I have the upcoming Thanksgiving weekend to do some wrenching on this car. I am leaning on replacing the EGR Valve (and possibly the cooler too). I am not sure on parts availability at present.

Let me know any other ideas!

Paul.
---------------------------------------
Vehicle VIN: 1G1RB6S51HU103213
Vehicle Manufacturer: Chevrolet
Vehicle Calibration ID: Not present

Current Fault Log
------------------
P0325: Knock Sensor 1 Circuit (Bank 1 or Single Sensor)
P0AC4: Unknown code - More information may be available on the web
P16E0: Unknown code - More information may be available on the web

Pending Fault Log
------------------
P00B7: Unknown code - More information may be available on the web
P0324: Knock Control System Error

Historic Fault Log
------------------
ECU reports no historic faults
Other discovered fault codes
(possibly pending, current or manufacturer specific)
----------------------------------------------------
ECU reports no other fault codes logged

End of report.
did you get it recently or did buy it new ?
 

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Discussion Starter · #12 ·
Sadly, I fixed the exhaust leak but I still get overheating. I took the car for a test drive after letting the engine warm up in my driveway. It went to 240F+ fairly shortly. I still have the P0324. P0325, P00B7 codes. Still no return of the P0401. F03 fuse still good. I will await the new EGR parts but could this be my thermostat? P00B7 is a low coolant flow code. And, I am getting high coolant temps. Maybe it is the thermostat??
 

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Is it possible that with the misplaced gasket coolant entered the exhaust manifold and got into a cylinder or two? That may cause misfires and high pressure and temperature. Could also cause a blown head gasket.
 
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