Nigel Triumph Posted April 8, 2020 Report Share Posted April 8, 2020 We have a 2006 BMW 318Ci as an everyday runaround. For those who know Beemers, it's an E46 with N42 engine. Recently it's started dripping coolant from the coolant level sensor in the bottom of the expansion tank. I've taken the sensor out, expecting to find an O-ring or similar rubber seal but couldn't see one, either on the sensor or in it's socket. Has anyone here got any experience of BMWs from this era? I've asked on a BMW forum and been told the whole expansion tank needs to be replaced but I don't know why and no explanation has yet been forthcoming. Please can anyone tell me how to get the sensor to seal into the existing expansion tank, or why I should change the tank? Nigel Quote Link to post Share on other sites
stuart Posted April 8, 2020 Report Share Posted April 8, 2020 Araldite. Stuart. Quote Link to post Share on other sites
Nigel Triumph Posted April 8, 2020 Author Report Share Posted April 8, 2020 8 minutes ago, stuart said: Araldite. Stuart. Thank you Stuart. The car isn't precious to us, other than its usefulness, so I was wondering about bodging it with silicone. Araldite sounds more permanent, and if the expansion tank does have to be replaced in the end, nothing lost. Nigel Quote Link to post Share on other sites
stuart Posted April 8, 2020 Report Share Posted April 8, 2020 Just now, Nigel Triumph said: Thank you Stuart. The car isn't precious to us, other than its usefulness, so I was wondering about bodging it with silicone. Araldite sounds more permanent, and if the expansion tank does have to be replaced in the end, nothing lost. Nigel Is its steel or plastic? You will need to get it dried off enough to get it to stick, rough the surface up a little to help as well. If its steel then a product like JB Weld would probably be more appropriate. Stuart. Quote Link to post Share on other sites
AndyR100 Posted April 8, 2020 Report Share Posted April 8, 2020 Stuart’s advice is spot on ....... Andy Quote Link to post Share on other sites
Nigel Triumph Posted April 8, 2020 Author Report Share Posted April 8, 2020 Thanks gents, The tank is plastic and I've realised the sensor fits in a pocket moulded into the tank, without coming into direct contact with the coolant. The leak therefore means there is a crack inside the tank or the pocket. To dry it out and clean sufficiently for Araldite to bond effectively, I'm going to have to get the tank out, including cutting a couple of one-time hose clips. Having gone that far, I may as well fit a new tank, they're only £20. Nigel Quote Link to post Share on other sites
HSM Posted April 9, 2020 Report Share Posted April 9, 2020 You need a new tank, they are prone to splitting ( common fault with age ) I have replaced many of these for my customers. Harvey S. Maitland Quote Link to post Share on other sites
Nigel Triumph Posted April 10, 2020 Author Report Share Posted April 10, 2020 I fitted a new tank this morning and the coolant leak is fixed. Thank you for your input and advice. Nigel Quote Link to post Share on other sites
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