Seal threads of non-tapered fitting

[Finnius]

Hi folks,
I am thinking of using some adapters to change the funny AC style pipe fittings used for the oil cooler lines in a 300TDi.

There is 2x m20x1.5 female fittings in the oil housing and i want to convert them to AN fittings.

I can get an adapter that goes from 10AN to m20x1.5, but of course the fitting is non-tapered and i feel that by just screwing them in nice and tight it wont guarantee oil pushing up through the threads and leaking.

Is a thread sealant such as permatex teflon sealant good enough for a job like this? Or will a non-tapered thread always leak in a situation like this?

Thanks!

[Tombie]

Best way - M20 Bonded Washer also known as a Dowty washer.

I’d also use a hydraulic sealant as a back up.

[p38arover]

Thanks Mike. I've never heard of the Dowty washer - but I have, of course, heard of George Dowty.

That looks to be a useful device.

[Bigbjorn]

Taper pipe threads seal on the threads. A sealant, teflon tape, or, long ago, plumbers hemp. Straight pipe threads usually have a gasket or o-ring.

[Finnius]

Wow!

I can't believe i haven't heard of those before. I googled them and found out how they work and they sound sooooo useful.

Is my local hardware/fastener shop likely to stock them or are they a specialty item that has to be ordered from somewhere?

[Tombie]

CBC, Pirtek and other hydraulic shops should have a range.

In Perth a quick trip to Hallite Transeals should see you sorted.

[Finnius]

Yeah, i am near Albany. Will have to hunt around or buy online i guess.

[p38arover]

Try a bearing supplier if you don't have Pirtek or similar.