Coolant Leak

makeitcount · Today, 07:18 AM

I'm losing about a litre of coolant about a few days after refilling my main reservoir back up (it doesn't seem to loose any more than just a litre even if I leave it for another few days) . Seems to be leaking from this reservoir/chamber in the attached image, which is covered in dried coolant just in front of the main reservoir, but I can't figure out what this is or a part name/number. I found it on an engine bay schematic but it says it's a turbo vacuum chamber... So I'm confused (and/or scared!) because it seems like it's the source of my coolant loss. Advice much appreciated plus if anyone has a part number or name.

2007 E93 335i N54

Many thanks.

Wolf 335 · Today, 08:00 AM

Those are vacuum tanks. They dont have anything to do with coolant.

What you are seeing is coolant spraying onto vacuum tanks while it is hot, expanded and pressurized.

Check that you don't have any leaks on the radiator or even overflow hose that is attached the to coolant tank. If you follow that hose it connects to either a metal pipe or a plastic one that runs on top of the radiator.
Sometimes they develop hairline cracks that could be to source of your coolant spraying out.

Inspect the radiator and also the flange that connects the thermostat coolant hose to the engine block. That flange cracks and leaks. If it is leaking you will see youre engine block is wet behind the drive belt.

Today, 07:18 AM	#1
makeitcount New Member 2 Rep 7 Posts Drives: 2007 335i Convertible Join Date: Nov 2021 Location: Australia iTrader: (0)	Coolant Leak - what is this component? (Noob) I'm losing about a litre of coolant about a few days after refilling my main reservoir back up (it doesn't seem to loose any more than just a litre even if I leave it for another few days) . Seems to be leaking from this reservoir/chamber in the attached image, which is covered in dried coolant just in front of the main reservoir, but I can't figure out what this is or a part name/number. I found it on an engine bay schematic but it says it's a turbo vacuum chamber... So I'm confused (and/or scared!) because it seems like it's the source of my coolant loss. Advice much appreciated plus if anyone has a part number or name. 2007 E93 335i N54 Many thanks. Attached Images Last edited by makeitcount; Today at 07:47 AM..
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Today, 08:00 AM	#2
Wolf 335 Brigadier General 2557 Rep 3,662 Posts Drives: 2007 E92 335i Join Date: Aug 2012 Location: Toronto iTrader: (0)	Those are vacuum tanks. They dont have anything to do with coolant. What you are seeing is coolant spraying onto vacuum tanks while it is hot, expanded and pressurized. Check that you don't have any leaks on the radiator or even overflow hose that is attached the to coolant tank. If you follow that hose it connects to either a metal pipe or a plastic one that runs on top of the radiator. Sometimes they develop hairline cracks that could be to source of your coolant spraying out. Inspect the radiator and also the flange that connects the thermostat coolant hose to the engine block. That flange cracks and leaks. If it is leaking you will see youre engine block is wet behind the drive belt.
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