AN fittings

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Discussion

Q_Plate

Original Poster:

349 posts

208 months

Wednesday
quotequote all
Looking for some advice please.

I’ve fitted some new oil lines between an oil filter sandwich plate and oil cooler, they are AN10 fittings on both ends. I’ve seated them carefully and tightened them sufficiently. Unfortunately I’m still getting some oil seapage from both ends, when I look into it people don’t recommend rubber O rings or and kind of sealant. Has anyone got any experience with this?

Thank you.

GreenV8S

30,849 posts

299 months

Wednesday
quotequote all
You need to use anti-sieze on the threads. If you fit them dry there's a danger of galling the threads, also not tightening them fully since some of the torque is lost to friction. The connical sealing face should always be dry. Cheap fittings can sometimes gall here too, so if it's tightened properly and still leaking you need to give it a visual inspection. You shouldn't need to add any form of seal to a typical joint, but if you're sure all the bits are completely compatible and in good condition and torqued properly and so on then it is possible to buy conical seals(conical crush washers) which should give you a perfect seal - I've never had to resort to that, though.

stevieturbo

17,764 posts

262 months

Yesterday (09:25)
quotequote all
Q_Plate said:
Looking for some advice please.

I ve fitted some new oil lines between an oil filter sandwich plate and oil cooler, they are AN10 fittings on both ends. I ve seated them carefully and tightened them sufficiently. Unfortunately I m still getting some oil seapage from both ends, when I look into it people don t recommend rubber O rings or and kind of sealant. Has anyone got any experience with this?

Thank you.
Explain better and exactly, with photos if need be.

AN by design are taper seat fittings, they just seal. Job done.

Obviously the AN side may adapt to other parts with different threads and designs which may require something else.

Or if the actual hose is not correct for the fitting, etc etc

E-bmw

11,023 posts

167 months

Yesterday (16:54)
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Shouldn't need anything, but having said that, in my previous existence as a hydraulic specialist I did come across some copper "washers" that were obviously shaped to fit the cone, but these were on HIGH pressure lines, such as 400 bar.

Is the weep definitely coming from the mating surface?

I ask as cheap AN fittings can only have 1 "peg" between the nut & back face of the fitting, so they can be trying to sit un-square if you understand what I mean.

GreenV8S

30,849 posts

299 months

Yesterday (17:16)
quotequote all
By the way, I've got a couple of fittings in my fuel system connecting hoses into filters where the hose end fittings are regular AN fittings (complete with the 37 degree conical seat) but they screw into housings without the corresponding conical mating surface - these joints are sealed by O rings. If you're having trouble getting it to seal, double check that you do actually have an AN style conical mating seat on both parts and that the hose end is actually bottoming out on that seat.