How to bleed coolant?

Tiny
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Here's some extra info on the cooling system flow, and other components. I don't see a lower intake manifold, like on a GM with a low manifold that bolts down in between the two heads, but this engine is a complex build for sure, there is a smaller bleeder on the pump itself, I'm not sure if there's a hose to it or if it's for just bleeding air right at the pump, but it's in diagram 6.
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Sunday, December 1st, 2024 AT 6:14 PM
Tiny
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I am going to test the ECT in cold and hot water. What should the ohm readings be in cold vs hot water?
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Monday, December 2nd, 2024 AT 8:08 AM
Tiny
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The plug on the front where the thermostat is reads ground on one pin and 3.5 on the other. Pin. Am not seeing ect 2 on any site, but disconnecting it made no difference in reading still reads 64f.
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Monday, December 2nd, 2024 AT 10:46 AM
Tiny
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Okay, you should definitely be reading 5volts on one of the wires when the sensor is unplugged. It looks like the Yellow wire should read 5volts, the other wire is the sensor ground through the ECM, there is a TSB that came up, I will post it, I havent gone through the entire bulleting yet, but it does mention a bypass hose that it supposed to help with airlock, which will cause the ECT to read incorrectly if air is trapped at the sensors location, ECTs cannot read the temperature of air, only liquid, but a low 5volt reference is concerning as well. One temp sensor is located on the front of the engine and the other on the rear (diagram 2) just above the flywheel area. This is the OEM wiring diagram that also shows two temp sensors, you may need to cycle the key for the temperature to change, or it might be the other sensor, I'm not 100% sure on the two sensors, if that's for a different engine setup, but it's just what I'm seeing, let me post this TSB though, I think it will resolve your coolant issue.
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Tuesday, December 3rd, 2024 AT 11:31 AM
Tiny
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So, here for this TSB they want another hose with 2 T fittings run to the coolant expansion tank to help bleed air out of the system. I would think you could do this without having to purchase these parts from the dealership, you would just need to find a couple cooling system T fittings and a section of coolant hose with some hose clamps to complete this TSB, even if you're not getting the codes setting P0126-26/P0128-00, obviously there's an issue with air pockets in this vehicle, that's giving you a lot of problems.
Diagram 12 explains the operations of the two ECT sensors.
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Tuesday, December 3rd, 2024 AT 12:01 PM
Tiny
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Wow, lots of great info. At least I know this MAY not just be me lol. I will get the fittings and hoses and get it done. I will also see if the back ECT is one that reads, cause whether I remove the front or leave it corrected it does not affect the readings.
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Tuesday, December 3rd, 2024 AT 1:13 PM
Tiny
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Oh and I was able to get 4.5 volts on one of the connectors. It was fluctuating based on how I touched it. What's the point of the second ect then if only one reads temp?
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Tuesday, December 3rd, 2024 AT 1:40 PM
Tiny
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I think that's why you're not seeing any change in the signal on scan data, and no I don't think the air being trapped in the system is your fault by any means. There are so many tiny hoses running all over the place, I've worked on these vehicles before, and I think they are just overly complicated. So hopefully this extra hose will allow more air out of the system, I would still use the vacuum bleed/draw down system. It's very effective and makes filling so much easier. Here's the ECM connector pinout so you can check the 5-volt reference at the ECM itself, the ECT sensors will need to be unplugged to check it with the key On, engine Off. It might be that the other ECT sensor is possibly faulty.
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Tuesday, December 3rd, 2024 AT 2:03 PM
Tiny
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It looks like there are two ECT sensors to verify the thermostat is working correctly, so probably one sensor on each side of the thermostat in the coolant jacket, this way the ECM can set a thermostat code if it doesn't see the correct change at certain temperatures.
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Tuesday, December 3rd, 2024 AT 2:07 PM
Tiny
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If you're moving the connector and it's affecting the 5volt ref, there is most likely a bad connection or wiring issue inside the insulation at the connector, even 4.5volts might throw the ECT's reading off somewhat. That's something I would investigate further.
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Tuesday, December 3rd, 2024 AT 2:08 PM
Tiny
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Will check it. No, it was more my hand moving and the voltmeter pins being too thick to insert.
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Tuesday, December 3rd, 2024 AT 2:11 PM
Tiny
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I am also getting a 64f reading and then it climbs gradually on scanner, so sensor works, if it was fluctuating on scanner I would have thought wiring, but I will open it and confirm.
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Tuesday, December 3rd, 2024 AT 2:12 PM
Tiny
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Going with the TSB repair sounds like a logical fix, there must have been quite a few complaints coming in about the coolant system for them to post a bulletin on it. But let us know how it goes.
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Tuesday, December 3rd, 2024 AT 2:39 PM
Tiny
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I checked the TSB and unfortunately the parts/kit is not available anywhere anymore. I know it's a couple of fittings but knowing what size is the issue. Are there T fittings that can have 2 ends with some size and a 3rd with say smaller size? Because the 3rd end would need to have a smaller size hose to go to the coolant expansion tank hose and attach o it, but its smaller in diameter.
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Friday, December 20th, 2024 AT 7:52 AM
Tiny
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I will take a look, since I'm checking on parts for another vehicle right now anyway. Basically, you need to find T fittings that can take the heat, I know when I go to AutoZone or local parts store for basic stuff, they have a section where they keep pretty generic hoses and random parts that are not for any specific model. Or do a google search for something equivalent to what you need. But I will look for a few minutes here. Sometimes you have to get creative if parts are not available from the dealership.
What size do you think you need for the T on the two fittings that are the same (outside diameter)? And then the smaller of the 3 fittings?
This was the non turbo engine as well, correct?
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Friday, December 20th, 2024 AT 8:05 AM
Tiny
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Rockauto has a section at the top of their page called "Tools and Universal Parts", they have some T fittings and also some reducers that could be installed into a hose to adapt it to whatever is needed, then could be hose clamped down, this is just an example of what you could do, I didn't really looks into what the specs and sizes are for these, it was just a quick search, but a google search for a coolant T fitting might yield better results.
The 2nd one is from AutoZone that has two the same and one smaller.
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Friday, December 20th, 2024 AT 8:16 AM
Tiny
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This coolant T fitting is actually from Walmart of all places. So, there are definitely fittings with multiple size hose adapters out there.
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Friday, December 20th, 2024 AT 8:20 AM
Tiny
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It is a non turbo. I will send you a video to show you what I mean. Is there a tool out there that is used to measure hose sizes on the inside? It's going to be hard to go back and forth to the store and buy 10 different ones before I get the right one. There is not much pressure on this heater core hose, same for the expansion tank hose.
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Friday, December 20th, 2024 AT 8:24 AM
Tiny
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Are you not able to measure the hose with it disconnected?
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Friday, December 20th, 2024 AT 9:07 AM
Tiny
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I have no way of doing that.
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Friday, December 20th, 2024 AT 9:10 AM

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