I have a brass temperature sensor about 14mm in diameter, no 'O' ring or shoulder, just seals on the threads into an aluminium cylinder head. What should I use to seal it? Nothing, ptfe tape, ordinary blue loctite, plumbing thread sealing compound (a bit too permanent I would think) or something else? Glad of any advice.
No taper at the end? PTFE tape won't do any harm.
I use ScotchClad thread sealer for everything that screws into my ally engine. It seals, prevents corrosion, and locks.
Thanks. The ScotchClad seems a bit elusive, though.
If Loctite don't make something exactly designed for this, I'll eat my hat.
Ooh. I don't own a hat. Hmm...
Yup - you'll not find it in Halfords. A car body shop that deals with 3M for paint should be able to order it for you. Comes in litre tins - last one I bought about £35. But of course will do hundreds of bolts, and that tin is lasting well. It's for all the world like a clear cellulose varnish. Full name ScotchClad 776. But I'm sure there will be a tube of loctite that does much the same.
That's what I tend to use on cars. Not sure how well it is rated as a sealant, but I suppose it is bound to works at least to some extent if it locks the threads.
Does it actually NEED sealing - ie is it going to leak coolant or does it screw into a blind pocket? I'd simply put a smear of anti sieze or a corrosion inhibiting heat sink compound on the thread if there's no leakage likely
It is potentially going to leak coolant.
A CTS normally pokes into the coolant.
I've just looked at a spare I have here for an SD1 Rover - ally head. It definitely has a taper at the end of the thread just below the hex.
Do you reckon ordinary blue (clone) Loctite is good enough? I'm not convinced taper threads should be used without sealant.
On the Rover, I've not heard anyone say you must use any sealant at all.
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