Bleeding Coolent Lines
Thread Starter
Instructor
Joined: Feb 2021
Posts: 230
Likes: 206
From: Port St. Lucie, FL
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Bleeding Coolent Lines
I've read where the LT2 engine has a special "bleeding" procedure when engine coolant is added.
I can't find any reference to it in the Manual.
Any thoughts on this?
I can't find any reference to it in the Manual.
Any thoughts on this?
Instructor
Joined: Dec 2022
Posts: 126
Likes: 77
From: Webster, NY
I'm not aware of the coolant bleeding procedure. I did add the aux V09 drive side radiator. I just ran the car up to temp, let it cool added coolant and repeated. It did a fine job of bleeding the system itself. Unlike my Porsche Boxster which requires you to pull a vacuum on the system and suck the coolant in.
j
j
Pro
Joined: May 2023
Posts: 635
Likes: 290
From: About an hour north west of Albany, NY
The bleeding process is not simple and time consuming. I had to have it done in Ohio on my way home from Louisianna. 2-3 hours if I remember correctly as they need to bring it up to operating temps, and let it cool back down, and essentially go throught the refill, heat cycle a couple of times. If you're just topping off, I don't think it's an issue.
Melting Slicks
Joined: Jan 2006
Posts: 2,297
Likes: 1,859
From: Oregon
I have not read the manual, but common sense is that the coolant overflow tank is the highest point in the system, so it should bleed out any air bubbles.
But, If you drain the system, that makes it a whole lot more complex.
Radiators up front and on the sides, that could be really complicated, forget about common sense, you need to read the manual for that.
But, If you drain the system, that makes it a whole lot more complex.
Radiators up front and on the sides, that could be really complicated, forget about common sense, you need to read the manual for that.
Racer
Joined: Mar 2021
Posts: 289
Likes: 200
I have not read the manual, but common sense is that the coolant overflow tank is the highest point in the system, so it should bleed out any air bubbles.
But, If you drain the system, that makes it a whole lot more complex.
Radiators up front and on the sides, that could be really complicated, forget about common sense, you need to read the manual for that.
But, If you drain the system, that makes it a whole lot more complex.
Radiators up front and on the sides, that could be really complicated, forget about common sense, you need to read the manual for that.
CF Community Team
Joined: Apr 2016
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From: Pittsburgh
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A GM service manual would be the best source of information
Team Owner
Joined: Feb 2013
Posts: 22,598
Likes: 14,555
The front radiators have bleed ports, but they're not accessible under normal operation and are really only needed if you replace major components. The system will self bleed over time. One tech buddy told me to leave cap off overnight with a shop towel over it and the air would migrate out itself. Said they generally do a good job self-bleeding and you don't need to mess with the front ports.
To just top off the system you don't need to do anything... just check it cold in the morning before you run the car and add fluid just over the "full" plate that you can see looking down into the reservoir. I don't even top off w/ coolant... I just used filtered water from my fridge.
Be warned, some of the cars are over-filled from the factory. One of my C8s spilled coolant all over the place even taking cap off cold in the morning. It was filled to the max of the reservoir and still had some residual heat from using it the day before. Makes for a sticky mess... I just ran the garden hose down in that area.
To just top off the system you don't need to do anything... just check it cold in the morning before you run the car and add fluid just over the "full" plate that you can see looking down into the reservoir. I don't even top off w/ coolant... I just used filtered water from my fridge.
Be warned, some of the cars are over-filled from the factory. One of my C8s spilled coolant all over the place even taking cap off cold in the morning. It was filled to the max of the reservoir and still had some residual heat from using it the day before. Makes for a sticky mess... I just ran the garden hose down in that area.
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Race Director
Joined: Aug 2016
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From: Garden Valley CA
The method in the owner's manual is for adding coolant. What I'm curious about is the procedure for replacing the coolant per the service schedule. I have an eBay copy of the service manual but I can't find the coolant replacement procedure (doesn't mean it isn't in there). I'd like to see the GM service procedure for replacing the coolant.
Race Director
Joined: Mar 2007
Posts: 11,362
Likes: 8,516
The method in the owner's manual is for adding coolant. What I'm curious about is the procedure for replacing the coolant per the service schedule. I have an eBay copy of the service manual but I can't find the coolant replacement procedure (doesn't mean it isn't in there). I'd like to see the GM service procedure for replacing the coolant.
Instructor
Joined: Nov 2024
Posts: 100
Likes: 70
What follows is a summary of the coolant fill and bleed procedure in the 2021 service manual. It is 28 steps.
Remove the covers (30 in the front.
Put absorbent rags around the auxiliary heater inlet and outlet intermediate hose cap. This is on both side of the frunk. Use needle node pliers to rotate the caps CCW and pull up. If coolant flows out put the cap back on. Note that is you've drained the system completely then this will occur when you are filling it.
Disengage the radiator inlet hose retainer and remove the inlet hose connector cover. This is next to the brake fluid reservoir. Again, when coolant comes out put the cover back on.
Next fill the system with a 40/60 mix of coolant until coolant comes out of the vents above. Close the vents
Start the engine. With AC OFF allow the engine to run for 10 minutes. Shut off the engine. Let the engine cool down (approx 10 minutes)
Repeat all the steps above.
Withe AC OFF, allow the engine to idle until one of the aux radiator outlet hoses becomes warm near the radiator, the coolant temp should approach 185F. If not repeat the steps above,
Remove the covers (30 in the front.
Put absorbent rags around the auxiliary heater inlet and outlet intermediate hose cap. This is on both side of the frunk. Use needle node pliers to rotate the caps CCW and pull up. If coolant flows out put the cap back on. Note that is you've drained the system completely then this will occur when you are filling it.
Disengage the radiator inlet hose retainer and remove the inlet hose connector cover. This is next to the brake fluid reservoir. Again, when coolant comes out put the cover back on.
Next fill the system with a 40/60 mix of coolant until coolant comes out of the vents above. Close the vents
Start the engine. With AC OFF allow the engine to run for 10 minutes. Shut off the engine. Let the engine cool down (approx 10 minutes)
Repeat all the steps above.
Withe AC OFF, allow the engine to idle until one of the aux radiator outlet hoses becomes warm near the radiator, the coolant temp should approach 185F. If not repeat the steps above,