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Do I need a new expansion tank?

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Griffo46
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Do I need a new expansion tank?

Post by Griffo46 » Tue Oct 04, 2022 11:27 am

Car - 2007 3.0si
So yesterday I checked the coolant level and the float was well below level. I topped it up and completed the bleed process. Float still remained at the bottom and the stick was definitely there.
Today, I checked level again and the stick has vanished, float there and coolant visible.
Shall I just consider getting a new tank and sensor?
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After
8A84A83F-EA29-4562-8B98-5509C04A7AB0.jpeg (145.77 KiB) Viewed 277 times
Before
Before
92FD2FE8-BDDE-466C-B93F-639D6834E652.jpeg (148.62 KiB) Viewed 277 times
2007 3.0si Roadster Stratus Grey/ Red Leather
2016 520d F10 M Sport Space Grey

JamesClements
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Do I need a new expansion tank?

Post by JamesClements » Tue Oct 04, 2022 5:48 pm

Its a fairly easy replacement - although when mine split it was spraying out the back of the tank after less than a mile and all over the engine - have you tried removing the plastic cover thingy (technical term :) ) on the radiator and checked for any staining/residue with a torch?
2006 Sapphire Black E86 3.0si | 108's, ZHP, Stubby, Eibach Springs
2007 Carbon Black E85 2.5i | 19" NAD alloys, Pilot Sport 4S, strut brace, Stubby, ZHP, Brembo 4 pots, Greenstuff pads, Alcantara retrim, roof motor in boot
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colb
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Do I need a new expansion tank?

Post by colb » Tue Oct 04, 2022 6:37 pm

Since you topped it up and its gone down since it must be leaking away somewhere, odds on the tank has a split that opens up when hot so probably best to put a new one in. As to the indicator stick not moving is that the case when you top it up it stays at the bottom?
Maybe the float is punctured and filled with coolant and causing it to stay at the bottom instead of floating. Best all round to replace the tank.
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Griffo46
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Do I need a new expansion tank?

Post by Griffo46 » Tue Oct 04, 2022 7:26 pm

I haven’t experienced any leaking yet, unless the amount is so small I can’t tell. I’m more worried about where the stick is, it’s not attached to the float in the ‘after’ photo. I think I’ll get a price on a new tank and consider a full flush too. Thanks for peoples feedback
2007 3.0si Roadster Stratus Grey/ Red Leather
2016 520d F10 M Sport Space Grey

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