coolant light no leaks level is good

Brett Krehling · 09-22-2019, 02:30 PM

hey guys been having a coolant light pop up on my 2011 135i whenever i start it and turn it off. i checked the coolant and its not low. i checked everywhere for a leak and none. next i went ahead and replaced the level sensor and its still on. i even went ahead and bled the entire coolant system. the car is not overheating as i stay below 220f. i was reading up and found that possibly the float in the expansion tank maybe stuck down causing my light to stay on. oh yeah i just had my waterpump thermostat and expansion tank replaced a month ago, this problem just started to occurred. if anyone has similar issues let me know what you did to fix it, my next step is to replace the whole expansion tank....

zx10guy · 09-22-2019, 03:38 PM

The coolant level sensor has been known to go bad. Try replacing it. It's located in the overflow tank so not hard to replace. You also may consider replacing the entire overflow tank as they're known to crack/leak with age. I just had to replace mine due to a crack causing coolant to leak out. I got an OE tank from FCP Euro which comes with the coolant level sensor.

dtla1 · 09-23-2019, 11:30 AM

I would say try to replace the level sensor again, and/or, double check that the wire that plugs into it is securely connected.

I bought a replacement tank with sensor from amazon, the level sensor went out in about a month.

MightyMouseTech · 09-23-2019, 11:41 AM

Check the connector that plugs into the sensor for corrosion, and the wiring going to the connector.

Brett Krehling · 09-23-2019, 08:30 PM

Quote:

Originally Posted by MightyMouseTech

Check the connector that plugs into the sensor for corrosion, and the wiring going to the connector.

so i had already replaced my coolant level sensor .. today the code is off...i drove it to and from work no light. my expansion tank is brand new.. turns out the float was stuck down causing the light to stay on. the coolant level sensor has a magnet that senses when the float is down lower than i should be, triggering the light to go off. i was informed this is actually normal with the seasons and weather changing. which the temps here in PA have been pretty drastic lately. glad this was something stupid and don't need to spend anymore lol

jaydieu · 01-02-2020, 12:58 AM

Quote:

Originally Posted by Brett Krehling

so i had already replaced my coolant level sensor .. today the code is off...i drove it to and from work no light. my expansion tank is brand new.. turns out the float was stuck down causing the light to stay on. the coolant level sensor has a magnet that senses when the float is down lower than i should be, triggering the light to go off. i was informed this is actually normal with the seasons and weather changing. which the temps here in PA have been pretty drastic lately. glad this was something stupid and don't need to spend anymore lol

How did you fix the float from staying down? I have the same problem, but when I check my coolant level, the float goes up to max. I just wanna make sure I don't have the same problem as you before I try to replace my sensor

dtla1 · 01-06-2020, 12:15 PM

Quote:

Originally Posted by jaydieu

How did you fix the float from staying down? I have the same problem, but when I check my coolant level, the float goes up to max. I just wanna make sure I don't have the same problem as you before I try to replace my sensor

I think you just give it a little tappy tap tap.

Dackelone · 01-13-2020, 03:10 PM

Replace the coolant tank and sensor with BMW (dealer)parts. Not aftermarket ones. The expansion tanks are known to blow apart with high mileage at the seam welds.

But before you do that... check the level sensor's wiring & harness. Look at the Terminals. Give the sensor's plug a good tug and see IF you have a marginal wire crimp(s).

Check the float when the engine is stone cold in the morning... the level should be a MIN on a cold engine.

Good Luck,
Dackel

09-22-2019, 02:30 PM	#1
Brett Krehling New Member 16 Rep 20 Posts Drives: 2011 Bmw 135i Join Date: Jun 2018 Location: Pennsylvania iTrader: (0)	coolant light no leaks level is good hey guys been having a coolant light pop up on my 2011 135i whenever i start it and turn it off. i checked the coolant and its not low. i checked everywhere for a leak and none. next i went ahead and replaced the level sensor and its still on. i even went ahead and bled the entire coolant system. the car is not overheating as i stay below 220f. i was reading up and found that possibly the float in the expansion tank maybe stuck down causing my light to stay on. oh yeah i just had my waterpump thermostat and expansion tank replaced a month ago, this problem just started to occurred. if anyone has similar issues let me know what you did to fix it, my next step is to replace the whole expansion tank....
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09-23-2019, 11:30 AM	#3
dtla1 Colonel 828 Rep 2,232 Posts Drives: 2011 135i, Space Grey Join Date: Apr 2014 Location: Silicon Valley iTrader: (2)	I would say try to replace the level sensor again, and/or, double check that the wire that plugs into it is securely connected. I bought a replacement tank with sensor from amazon, the level sensor went out in about a month.
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09-23-2019, 11:41 AM	#4
MightyMouseTech Major General 4338 Rep 6,196 Posts Drives: 13 135i 6MT LeMans Blue MSport Join Date: Feb 2013 Location: Ottawa, Canada iTrader: (0)	Check the connector that plugs into the sensor for corrosion, and the wiring going to the connector.
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01-13-2020, 03:10 PM	#8
Dackelone European Editor 10589 Rep 22,992 Posts Drives: N54 e82 Join Date: Feb 2010 Location: Bayern, Germany iTrader: (1)	Replace the coolant tank and sensor with BMW (dealer)parts. Not aftermarket ones. The expansion tanks are known to blow apart with high mileage at the seam welds. But before you do that... check the level sensor's wiring & harness. Look at the Terminals. Give the sensor's plug a good tug and see IF you have a marginal wire crimp(s). Check the float when the engine is stone cold in the morning... the level should be a MIN on a cold engine. Good Luck, Dackel __________________ Dackel's European Delivery Museum Guide
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