BMW Z4 COOLANT LEAK! sigh..

BMWZ42.2I · 05-02-2014, 04:46 AM

I noticed in the last week that my coolant light would flash on, stay on for a few minutes and then disappear. I checked the manual and it said to add coolant. I popped a coolant in there as it was low and hence the reason why the light when on then off. The light didn't come on again for a day, but today it came on and stayed on longer. The temperature gauge is right smack in the middle which is where it has always been. I believe there is a leak somewhere. I looked online and apparently coolant leak is very common especially on the expansion tank.

update:

My mechanic mate spotted some leak on the expansion tank. It was bloody $300 nzd. ($250+ usd). It came with the O ring side the tank.

but there were no o rings on the expansion connecter to hose. Apparently I cant just buy the o ring itself but is it necessary to change the hose as well? Hose comes with the o ring.

does anyone has experience with these?

dharper · 05-02-2014, 06:39 AM

It might be best to replace the entire tank. These are known to deteriorate over time and fail. I replaced the tank in mine as it had developed a crack that was small at first, but then became worse as the tank heated and cooled with the coolant cycle. It is a snap-together system (those O rings fit inside grooves) and is pretty easy to work on.
Good luck with the fix.

05-02-2014, 04:46 AM	#1
BMWZ42.2I New Member 2 Rep 13 Posts Drives: BMW Z4 2.2I Join Date: Jul 2013 Location: New Zealand iTrader: (0)	BMW Z4 COOLANT LEAK! sigh.. I noticed in the last week that my coolant light would flash on, stay on for a few minutes and then disappear. I checked the manual and it said to add coolant. I popped a coolant in there as it was low and hence the reason why the light when on then off. The light didn't come on again for a day, but today it came on and stayed on longer. The temperature gauge is right smack in the middle which is where it has always been. I believe there is a leak somewhere. I looked online and apparently coolant leak is very common especially on the expansion tank. update: My mechanic mate spotted some leak on the expansion tank. It was bloody $300 nzd. ($250+ usd). It came with the O ring side the tank. but there were no o rings on the expansion connecter to hose. Apparently I cant just buy the o ring itself but is it necessary to change the hose as well? Hose comes with the o ring. does anyone has experience with these?
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05-02-2014, 06:39 AM	#2
dharper BMW CCA Member 29 Rep 90 Posts Drives: '19 BMW X3 30i-'11 BMW 128i Join Date: Oct 2009 Location: Music City area iTrader: (0) Garage List 2016 BMW 328i [0.00] 2011 BMW 128i Cabrio [0.00]	It might be best to replace the entire tank. These are known to deteriorate over time and fail. I replaced the tank in mine as it had developed a crack that was small at first, but then became worse as the tank heated and cooled with the coolant cycle. It is a snap-together system (those O rings fit inside grooves) and is pretty easy to work on. Good luck with the fix.
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