Urgent: Boiling coolant, water pump working and loosing coolant

humbertob · 11-15-2017, 09:12 PM

Hi there, I'm having an issue with my son's car is a 2011 BMW 335i with the N55 engine, tonight he just called me and tell me that the low coolant warning was on, when he arrived home I just checked the car, is loosing coolant but I haven't pinpoint the leaking point, in the coolant reservoir you can hear the coolant boiling, the only leaking I'm seeing is in the coolant reservoir area, I was thinking that may be the thermostat or water pump is going because the car has 103K on the ODO, I just applied the coolant bleeding procedure and the water pump is working, just scanned the car and no codes at all, just the low coolant warning on the dashboard, any ideas on how to deal with this issue? Do I need to replace the water pump and thermostat or just replace the coolant reservoir, what would you do in this situation?

Thanks again for your help guys !

Welcome to NBA Jam · 11-15-2017, 09:19 PM

If your coolant is boiling, your system is not holding pressure somewhere. From your symptoms, your first bet will be to replace the coolant tank. It is cheap and easy to replace. It'll cost you maybe $50.

Riick · 11-15-2017, 09:28 PM

My radiator started leaking around 110k. They're like $120 shipped and insanely simple to replace with basic hand tools

weehe126 · 11-15-2017, 09:50 PM

Probably a cracked expansion tank. It's probably not boiling but you are hearing the return back into the tank.

humbertob · 11-15-2017, 10:14 PM

Thanks a lot for all your replies, Coolant tank is on it's way !

robthewrench · 11-16-2017, 09:21 AM

I don't think you hear boiling from too high a temperature. I think you hear coolant flow with trapped air. Start with the coolant tank. With no codes or overheat warning from the engine I would not jump to the waterpump yet.

Supermoon · 01-28-2018, 12:33 PM

Quote:

Originally Posted by humbertob

Thanks a lot for all your replies, Coolant tank is on it's way !

Did it fix the problem? I'm having the same issue right now.

humbertob · 01-28-2018, 06:28 PM

Quote:

Originally Posted by Supermoon

Quote:

Originally Posted by humbertob

Thanks a lot for all your replies, Coolant tank is on it's way !

Did it fix the problem? I'm having the same issue right now.

Yes replaced the coolant reservoir and the problem did go away for a week then one week later the radiator went bad and has been replaced also ! I think that when a coolant reservoir go wrong it's better to replace the entire cooling system for sure !

Supermoon · 02-01-2018, 10:13 PM

Quote:

Originally Posted by humbertob

Quote:

Originally Posted by Supermoon

Quote:

Originally Posted by humbertob

Thanks a lot for all your replies, Coolant tank is on it's way !

Did it fix the problem? I'm having the same issue right now.

Yes replaced the coolant reservoir and the problem did go away for a week then one week later the radiator went bad and has been replaced also ! I think that when a coolant reservoir go wrong it's better to replace the entire cooling system for sure !

Quote:

Originally Posted by humbertob

Quote:

Originally Posted by Supermoon

Quote:

Originally Posted by humbertob

Thanks a lot for all your replies, Coolant tank is on it's way !

Did it fix the problem? I'm having the same issue right now.

Yes replaced the coolant reservoir and the problem did go away for a week then one week later the radiator went bad and has been replaced also ! I think that when a coolant reservoir go wrong it's better to replace the entire cooling system for sure !

Thanks. I brought new parts to a local shop and they kept saying my cooling system is clogged b/c there's no visible crack on the tank.

They refused to work on my engine and sent me off to a small dealership. The SA worried about possible head gasket issue and sent me to a larger dealership.
I explained the SA there about the coolant reservior issue and he didn't buy it b/c he's never seen it happening.

They found no oil in coolant and pressure test didn't reveal any clog other than reservoir leaking coolant.
Then they admit it's the reservoir and I should wait for the parts to arrive.

Luckily I was prepared. I opened my trunk and handed him a set of genuine bmw coolant reservoir and cap.
I love this community and its archive of shared knowledge.

mweisdorfer · 02-02-2018, 11:00 AM

Put a dye in the coolant and see if you find where it's coming from.

11-15-2017, 09:12 PM	#1
humbertob First Lieutenant 137 Rep 318 Posts Drives: '16 BMW M235i Join Date: Jan 2013 Location: Laredo, Tx. iTrader: (0)	Urgent: Boiling coolant, water pump working and loosing coolant Hi there, I'm having an issue with my son's car is a 2011 BMW 335i with the N55 engine, tonight he just called me and tell me that the low coolant warning was on, when he arrived home I just checked the car, is loosing coolant but I haven't pinpoint the leaking point, in the coolant reservoir you can hear the coolant boiling, the only leaking I'm seeing is in the coolant reservoir area, I was thinking that may be the thermostat or water pump is going because the car has 103K on the ODO, I just applied the coolant bleeding procedure and the water pump is working, just scanned the car and no codes at all, just the low coolant warning on the dashboard, any ideas on how to deal with this issue? Do I need to replace the water pump and thermostat or just replace the coolant reservoir, what would you do in this situation? Thanks again for your help guys ! __________________ (OO)-(////)(\\\\)-(OO) '16 F22 M235i '19 G01 X3 \| Wife's '15 F30 335i M-Sport \| Son's '10 Porsche Boxster
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11-15-2017, 09:19 PM	#2
Welcome to NBA Jam Is it the shoes!? 3895 Rep 5,111 Posts Drives: (Sold) 2011 E92 335i ZMP 6MT Join Date: Mar 2014 Location: USA iTrader: (1)	If your coolant is boiling, your system is not holding pressure somewhere. From your symptoms, your first bet will be to replace the coolant tank. It is cheap and easy to replace. It'll cost you maybe $50.
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11-15-2017, 09:28 PM	#3
Riick Banned 136 Rep 818 Posts Drives: BMW Join Date: Feb 2014 Location: USA iTrader: (0)	My radiator started leaking around 110k. They're like $120 shipped and insanely simple to replace with basic hand tools
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11-15-2017, 09:50 PM	#4
weehe126 Brigadier General 1189 Rep 3,228 Posts Drives: 2017 340i Join Date: Apr 2014 Location: San Antonio iTrader: (2)	Probably a cracked expansion tank. It's probably not boiling but you are hearing the return back into the tank.
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11-15-2017, 10:14 PM	#5
humbertob First Lieutenant 137 Rep 318 Posts Drives: '16 BMW M235i Join Date: Jan 2013 Location: Laredo, Tx. iTrader: (0)	Thanks a lot for all your replies, Coolant tank is on it's way ! __________________ (OO)-(////)(\\\\)-(OO) '16 F22 M235i '19 G01 X3 \| Wife's '15 F30 335i M-Sport \| Son's '10 Porsche Boxster
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11-16-2017, 09:21 AM	#6
robthewrench Captain 266 Rep 950 Posts Drives: 11 E90 335i Join Date: Aug 2014 Location: Columbus OH iTrader: (0)	I don't think you hear boiling from too high a temperature. I think you hear coolant flow with trapped air. Start with the coolant tank. With no codes or overheat warning from the engine I would not jump to the waterpump yet. __________________ bone stock
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02-02-2018, 11:00 AM	#10
mweisdorfer Major General 1937 Rep 6,965 Posts Drives: 2007 Black/Black 335i e90 Join Date: Apr 2011 Location: Holly, MI iTrader: (0) Garage List 2007 BMW E90 335i [0.00] 2008 bmw x5 [0.00]	Put a dye in the coolant and see if you find where it's coming from.
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