Coolant leak

[Rmd143]

Has anyone had an issue with the overflow bottle leaking at the o'ring on the lower nipple? I've replaced the bottle and now it leaks at the second o'ring. one of the two nipples on the bottom of the bottle has a retaining clip the other doesn't. It leaks from the one that doesn't. I thought it was leaking from the drain cock and tried to tighten it and it snapped so I replaced the bottle housing mount bracket. Still the same issue. Any tips on getting the bottle to seat properly in the housing? Im thinking of changing the bottle back to see if the issue follows.

 

[bigwinn]

I usually grease them when reinstalling- there is always a solid ‘klunk’ when they seat in place

 

[TriggerFish]

You can get replacement o ring if it helps

BMW Z4 2.2i 2.5i 2.5si 3.0 3.0si 3.2 Cooling System Radiator Hose O-Ring Kit | eBay UK

But don't waste money buying a new sensor or unnecessarily replacing hose assemblies, all of which can last well beyond 10 years/150,000 miles. These o-rings seal the BMW press & clip hose connections.

ebay.us

I have found them to dry out and not reseal once disturbed

 

[firebobby]

When I changed my radiator and cleaned and put silicone grease on all the old seals. No leaks so far.

 

[Rmd143]

I lubed the seals and the orings were new. I've put the old bottle back in and it doesn't seem to be leaking. The new bottle wasn't OEM so lesson learned.