Crush washers on AN fittings?

[RNajarian]

I'm in the process of getting the necessary hardware to install a fender mounted oil cooler. At two points I will be joining a male AN12 fitting to a female AN12 fitting.

Is it recommended to put a crush washer (or any other type of washer) between them?

Thanks

[Oh Haha]

No washers needed on AN fittings.

[RNajarian]

Thanks! That means I have everything I need

[pampadori]

The flares on the fittings are what seal. They are cut at 37° on one and just a touch more than -37° on the other. As the fittings are tightened they come into one another and seal extremely well.
AN and JIC are basically the same except for the material and tolerances on AN are a touch better/tighter.

I always smirk a little when I see AN or JIC fittings connected with plumber's tape on the threads. No flare fitting ever required it for a seal.

[AsleepKat]

Being in aviation for the last 20+ years, I can tell you that there are rare instances where you will see an aluminum crush washer used, but usually in a fuel application. On our cars however, it's not needed for the exact reason that RNajarian pointed out.

[Tippy]

They have a 37° cone not requiring a washer. IIRC, standard flared fittings for general run 45°.

My understanding from tech school was to prevent non-aviation grade fitting from being attached.

[TimT]

In cases where a fitting is buggered up, and you have problems getting a leak free joint there are solutions... New fittings... no washer...

Seco seals from Pegasus

[gtc]

Originally Posted by pampadori

I always smirk a little when I see AN or JIC fittings connected with plumber's tape on the threads. No flare fitting ever required it for a seal.

Probably the same people that insist on new washers and nylock nuts on valve covers so they don't leak...