Anti_Climax
Posts: 166
Joined: Fri May 20, 2016 12:22 pm
Location: The Valley of the Sun

Re: The cooling problems continue

Wed Sep 29, 2021 2:41 pm

I got it warmed up to the point where it turned on the chiller and had the pump running at 50% and there is the tiniest dribble of coolant coming up from that side into the reservoir.
2012 Candy Blue FFE
33.5kWh battery pack
CHAdeMO DC Fast Charging

davideos
Posts: 415
Joined: Mon Jan 21, 2013 8:58 pm
Location: So Cal

Re: The cooling problems continue

Wed Sep 29, 2021 3:46 pm

Sorry for the late reply. Yes, that's what I was talking about. There are two of these de-gas lines...I think that's what they call them. I believe the batter loop de-gas line is just under the "cover" and to the right side...drivers side. It is just behind a diverter valve. That line goes back toward the cabin, to the left, and the forward to the coolant reservoir. The second line is at the right side of the radiator and not the one you're interested in.

When mine was running correctly, there was a small stream of coolant coming out of the line. I would think it would indicate your pump is working. Although, it just means there is positive pressure at that point in the coolant loop.

However, when I did all this, and even took it to the dealer to purge the air out of the cabin heater loop, I did have an odd issue where the reservoir became completely full and pressurized. Air somehow got introduced into the system. I opened the reservoir and coolant came gushing out. I let it cool down, added replacement coolant and it never happened again. Anyway, I don't think that story has anything to do with your issue.

Heima
Posts: 178
Joined: Thu Feb 21, 2019 11:46 pm

Re: The cooling problems continue

Wed Sep 29, 2021 5:32 pm

Don't know if this will help, but I just discovered this FFE thermal video:
https://www.youtube.com/watch?v=bJQ4N1QjnE8

Anti_Climax
Posts: 166
Joined: Fri May 20, 2016 12:22 pm
Location: The Valley of the Sun

Re: The cooling problems continue

Thu Sep 30, 2021 7:02 am

I've already diagrammed it all out from the exploded views in the service manual - unlike that diagram in the video, I managed to get it all in a single plane with no crossings. Although I will be sanity checking it to see if I missed anything.

At this point I'm going to need to drain it and splice in several test valves that will allow me to isolate flow in the separate sections to see where coolant is getting blocked. There's no other reasonable cause I can think of. The compressor runs, the chiller cools, the pump runs (and has been replaced) and the filter behind it has been replaced twice.

Yet the temps I see when the car "runs" while fully charged and plugged in (so the electronics are all being fed from DCDC powered by output from the SOBDM instead of the battery) suggest that warm coolant is convecting up from the SOBDM toward the battery over time, which should not be happening if there was free flow of the coolant. At least that suggests the blockage isn't in that section either, so less to pull apart.
2012 Candy Blue FFE
33.5kWh battery pack
CHAdeMO DC Fast Charging

Anti_Climax
Posts: 166
Joined: Fri May 20, 2016 12:22 pm
Location: The Valley of the Sun

Re: The cooling problems continue

Thu Sep 30, 2021 8:47 am

If anyone is interested in the schematic he has in that video, I think it's from this PDF

https://www.macheforum.com/site/attachm ... -pdf.3825/
2012 Candy Blue FFE
33.5kWh battery pack
CHAdeMO DC Fast Charging

Anti_Climax
Posts: 166
Joined: Fri May 20, 2016 12:22 pm
Location: The Valley of the Sun

Re: The cooling problems continue

Fri Oct 01, 2021 9:18 am

I used the diagram in that video to sanity check the one I created myself and it doesn't look like I had anything out of place - though it did let me add stuff like the degas lines, temperature sensors and one-way coolant paths. I've created a planar diagram (no crossings) for folks to reference.

Image

I may update this later with annotations on different lines like he has as well as color coding the loops. Diodes and arrows on my diagram indicate one-way coolant flow paths. The use of transistors was merely to have a symbol that allowed for a 3-way junction, though their arrow does indicate the direction of a known one-way coolant path wherever they appear. Text from his diagram reads as:

Priority Logic
A. Control Battery Circuit Temp
B. Control Motor Circuit Temp
C. Control Cabin Temp
D. Vehicle Performance/Range

MACS Circuit Cooling
ECO: Pump low-output directed to bypass conduit
Standard: Pump high-output directed to radiator
Cabin: Pump high-output directed to heater core (mild heat)

HVB, BCCM & BECM LOGIC
3 Cooling Modes:

First Cooling Condition: Desired temp Lower than Actual temp: Determine which condition is also present (2nd or 3rd condition).

Second Cooling Condition: Motor Circuit fluid tempt lower than desired battery temp. If yes, Cooling Mode A: Valve in 1st position to permit fluid flow from Motor Circuit to Battery Circuit. A/C OFF (no flow to chiller)

Third Cooling Condition: Motor Circuit fluid temp higher than desired battery temp. If yes, Cooling Mode B: Valve position #2 (Isolating battery circuit from motor circuit), Enable Battery Circuit Pump, A/C On (permitting flow through chiller)

Fourth Cooling Condition: Motor Circuit fluid temp equal to desired battery temp. If yes, Cooling Mode C: Valve in 1st position to permit fluid flow from Motor Circuit to Battery Circuit and A/C Chiller On. This allows coolant flow from radiator to chiller.

Cabin Heat
2 Heating Modes:

First Heating Condition: Warm fluid from MECS OUT re-routed to cabin heater core inlet. Outlet from heater core routed to MECS bypass (to cool MECS motor). heater pump low speed to avoid coolant flow to bypass heater core.

Second Heating Condition: Valve closed which recirculates heater.
2012 Candy Blue FFE
33.5kWh battery pack
CHAdeMO DC Fast Charging

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