Alloy header tank

[Lotus520]

I’ve just fitted an alloy header tank and thought I would share how I fitted the low level coolant sensor.
The new tank came with an M8 threaded insert that was and the original tank has a small rubber bush/ grommet which was a tight fit on the probe,
I used an M8 nylon bolt and washer and drilled a 5mm hole through the centre of the bolt on a lathe, and roughed up the necessary surfaces with some fine emery cloth and then cleaned everything up with panel wipe. I then fitted the probe through the bolt using high temp silicone gasket and allowed to cure.
I then put an M8 nut on to the bolt and applied some high temp epoxy putty where the probe exited the bolt ( the end that sits inside the tank) I then took the M8 nut off carefully to make sure no putty was fouling the thread. Lastly, I put some high temp silicone gasket around the M8 threaded insert/ flange and fitted the probe, just nipping it up with a 13mm spanner.
I’m really pleased with how it went and hope this thread helps someone out

[Hawaiis0]

Ideal for me as I will need to do something similar at the re-build

[rbgosling]

Interesting - my alloy header tank had a hole that fitted the original rubber grommet, so I could just re-fit as original. Mine was from SJ - where did you get yours?

Also, a word of advice from my experience - USE ALUMINIUM NUTS AND WASHERS!!! I originally used steel ones (probably not stainless, I can't recall for sure), and the first time I had to remove them the welded-in aluminium bolts snapped with barely any spanner load. SJ were at least kind enough to fix it for me for free. I found some cheap ones from this seller on eBay.