As I dig deeper into the CVC I've just removed the expansion tank and either I or a previous meddler has formed a very small crack in the breather pipe on the base of the expansion tank. Has anyone had any luck plastic welding the crack or would araldite bond well enough?
Makes a change, they normally crack on the side about where the Max level line is. Araldite won't bond property, plastic welding might work or just get a new one https://www.lrdirect.com/ESR2935-Coolant-Expansion-Tank-New-Rr-V8/?gclid=Cj0KCQjwtr_mBRDeARIsALfBZA6eVCzwWt0pJR5v2hhXAJcMkzF8KyaHcF8StFd2mANk-wpKEOMSvUEaAhoLEALw_wcB
Thanks Gilbertd, yes it makes sense to get a new one a few litres of antifreeze round the restored engine bay is not a good look.
I replaced my expansion tank with a BMW one that has a level switch in it. I wired it up to a light behind the dash.
Got a part number for the BMW one? Or a year/model/engine spec?
It is off an E36 or M3 model. bmw expansion tank part no. 17111712641
He are a few examples off Ebay:
https://www.ebay.co.uk/dsc/i.html?LH_TitleDesc=1&_nkw=bmw+expansion+tank+e36+17111712641
New, they are a bit pricey, like all BMW parts but they do come up cheaper from time to time on Ebay.
On a RHD car you will need to modify the mounting bracket to move it an inch to the left to clear the brake modulator. The hose connection comes straight out so you have to inventive with silicone tubing and a coupler. The level sensor works back to front as well. It is nc and goes open circuit as the coolant level drops, so I reversed the action through a relay.
I have since moved the relay. I didn't like where it was.