HELP!!! Coolant Bubbling Sound

[Amfchang]

After I shut my car off, or open the door after auto shut off, within 10 seconds there is a slight bubbling sound for a few seconds in the cabin. I bled the coolant several times, electronically and manually but I still hear it. This means the bmw accessory mode, the turning on engine and auto rev, the manual coolant bleed funnel and sucking out the fluid after to bring the level back to max. Multiple times. No coolant loss over the course of 10k miles but still happens and it worries me.

I have a 2020 pure 800 CONSERVATIVE 92 octane tune. Never ran ethanol. This is my daily driver and I never see the temperature gauge go above the fourth level bar. I don’t see coolant spraying anywhere in the engine bay. I was thinking if there was a leak then there would be coolant loss but it remains EXACTLY the same or if it was slightly overfilled, it never goes below the max tab line.

some said this might be normal because coolant expands and transfers over causing a slight intermittent b

I only notice it where I drive a good distance and come back home.

please help!

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[lucky phil]

What makes you think it's engine coolant? What about the air conditioner evaporator? Have you checked the A/C charge?

Phil

 

[Amfchang]

What makes you think it's engine coolant? What about the air conditioner evaporator? Have you checked the A/C charge?

Phil

I haven’t checked but the AC runs both hot and cold normally. There isn’t any issue in there whatsoever with temperatures.

 

[lucky phil]

I haven’t checked but the AC runs both hot and cold normally. There isn’t any issue in there whatsoever with temperatures.

I have a room split system AC that works fine but makes all sorts of noises as you've described for a few seconds after it's turned off. Just a thought.

Phil

 

[Lonestar_Nomad]

After I shut my car off, or open the door after auto shut off, within 10 seconds there is a slight bubbling sound for a few seconds in the cabin. I bled the coolant several times, electronically and manually but I still hear it. This means the bmw accessory mode, the turning on engine and auto rev, the manual coolant bleed funnel and sucking out the fluid after to bring the level back to max. Multiple times. No coolant loss over the course of 10k miles but still happens and it worries me.

I have a 2020 pure 800 CONSERVATIVE 92 octane tune. Never ran ethanol. This is my daily driver and I never see the temperature gauge go above the fourth level bar. I don’t see coolant spraying anywhere in the engine bay. I was thinking if there was a leak then there would be coolant loss but it remains EXACTLY the same or if it was slightly overfilled, it never goes below the max tab line.

some said this might be normal because coolant expands and transfers over causing a slight intermittent b

I only notice it where I drive a good distance and come back home.

please help!

This can be a couple of things. Failed rad cap, blown head gasket, stuck thermostat, air trapped in the system somewhere. Something to remember is the coolant reaches its highest temp immediately after shut off. The fan is no longer running and the coolant is half stagnant but also “flowing” by pressure and active condensation alone. Sometimes you can hear that process as bubbling. A decent mechanic can rule out the cap, head, and thermostat pretty quickly. And honestly some vehicles just do it. Both my jeep wranglers sounded like a crawfish boil after shutting them off.

edit* since you’ve has some work done on this car also double check all your PCV hoses etc.

 

[Amfchang]

What makes you think it's engine coolant? What about the air conditioner evaporator? Have you checked the A/C charge?

Phil

Oh shit I didn’t know that. Thank you so much. Because I would heather deal with ax issue than coolant…

 

[Amfchang]

This can be a couple of things. Failed rad cap, blown head gasket, stuck thermostat, air trapped in the system somewhere. Something to remember is the coolant reaches its highest temp immediately after shut off. The fan is no longer running and the coolant is half stagnant but also “flowing” by pressure and active condensation alone. Sometimes you can hear that process as bubbling. A decent mechanic can rule out the cap, head, and thermostat pretty quickly. And honestly some vehicles just do it. Both my jeep wranglers sounded like a crawfish boil after shutting them off.

edit* since you’ve has some work done on this car also double check all your PCV hoses etc.

the Only line I can’t see it the coolant line to the turbo and block but I’d figure there’s some loss of coolant if there was some sort of leak. With the radiator cap, I’d figure there would be some sort of spray residue around the cap seal or area but nothing. So the last two options are stuck thermostat and blown head gasket. Hopefully and I pray it’s not. My tune is super conservative but I understand there can be anything that’s factored. I’m not sure if I know how to tell for a thermostat but I’m praying it’s what you’re saying. It’s always for only a few seconds like it was flowing the last bits out of a water bottle into a tank.

 

[Lonestar_Nomad]

the Only line I can’t see it the coolant line to the turbo and block but I’d figure there’s some loss of coolant if there was some sort of leak. With the radiator cap, I’d figure there would be some sort of spray residue around the cap seal or area but nothing. So the last two options are stuck thermostat and blown head gasket. Hopefully and I pray it’s not. My tune is super conservative but I understand there can be anything that’s factored. I’m not sure if I know how to tell for a thermostat but I’m praying it’s what you’re saying. It’s always for only a few seconds like it was flowing the last bits out of a water bottle into a tank.

Most of the time I saw this it was a bad cap or a cracked/badly secured fitting letting air into the system as the heat/pressure rises after shut down. The air inside lets the coolant begin to boil. Any coolant losses could be so small you’ll never notice for weeks. As mentioned above the A/C can also do this as refrigerant is boiling off inside the system but that’s very simple to rule out. Run the car with ac completely off for a bit, let everything come up to temp and shut if it. If the bubbling stopped then you’ve got your answer. Good luck on the hunt!

 

[pdxnkh]

Did you ever figure this out?

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