Sealing Temperature Sender

[William2]

My car has a very small leak around the temperature gauge sender union that screws into the cylinder head. What is the best product for helping to seal the threads. I have noticed that on my particular union adaptor that the threaded part that screws into the head is shorter than the other side which doesn't help to get a good seal.

[KevJ+2]

I think I would use pva tape on the thread.

[KevJ+2]

Hmmm...thought about this. Although I did this on mine and all was okay, I suppose it could cause a loss of earth connection if too much is used or needed!
Just an afterthought

[billwill]

You need to say whether it is an electrical sensor (plus 2s) or a ether-vapour-pressure bulb and capillary tube (2--seater Elans).

The bulb type seals well with the white slippery PTFE plumbing tape.

[Elan45]

If you have the capillary tube type, there is a very narrow copper crush washer that goes into the bulb/ adapter connection. It will leak w/o the washer! I use teflon tape on the adapter/ head connection.

Roger

[mbell]

Hmmm...thought about this. Although I did this on mine and all was okay, I suppose it could cause a loss of earth connection if too much is used or needed!
Just an afterthought

I doubt it. It's a low current circuit, so would only need a very small contact patch to operate fine. Generally PVC tape will end up filling the gaps between the two threads where they occur and will be removed from the areas that the two threads are tight. Meaning the area it ends up wouldn't have provide a good electric connection to start with, so the PVC is insulating some that wasn't a connection anyway. It is removed from the tight metal to metal areas leaving a good connection.