Plumbing cooling lines NPT vs. flare

[Turbo67camaro]

I'm planning the plumbing of my cooling lines for a 4L80E.

From what I understand, the holes in the transmission for the lines are 1/4" NPT. The rear cooling line, requires the special fitting (i.e. Sonnax fitting), for proper fluid flow.

I'm leaning towards using hard lines instead of braided stainless.

The Sonnax fitting has a 1/2" 20 thread inverted flare female fitting for the rear. The front fitting, on the trans, is 1/4 NPT (I believe - not positive).

It seems that finding the hard line plumbing components is easier if I stick to NPT. Will NPT seal well enough? Should I use teflon tape on all NPT connections?

Or, should I try to make as many of the connections using inverted flare type connections for better seals?

[Steve Chryssos]

NPT seals on the threads, so teflon tape is a must. Inverted Flare seals on the beveled face--definitely better. I've always used AN with braided hose for it's flexibility. I can route the lines around the bell and up along the starter and oil pan. Keeps the lines away from the headers. And the hose flexibility is even more desirable in the tunnel area where clearance is minimal and hose curvature is to be expected. Lastly, I use AN adapter fittings near the core support for easy disassembly where access is best. That way my primary lines get capped of and come down with the trans.

That's just my way of doing things, but I think I would go nuts trying to accomplish all of the above with hard lines.

[parsonsj]

The only thing I can add is that I prefer Teflon paste, rather than tape.

But otherwise, what Steve said.

jp

[1969CamaroRS]

...but I think I would go nuts trying to accomplish all of the above with hard lines.

I guess I'm nuts then

I plan on doing 3/8ths hardline from the trans along the bottom of the block, all the way to the front of the block, then switching to braided hose to the cooler. Same thing on the other side of the block for oil cooler as well (just -10 or 5/8ths this time).

I don't like the teflon tape thou, had problems with that stuff coming apart and getting in places it shouldn't. I have used the ARP thread sealer with good results on just about everything that needed the threads water tight.

[Turbo67camaro]

Thanks for the great info!

I should be able to make an informed decision now.

I may chicken out on the hard lines. While I think they would look better if cleanly installed, it is more work, and the more I choose more work, the longer this project takes to complete.

[Captcloud]

I'm planning the plumbing of my cooling lines for a 4L80E.

From what I understand, the holes in the transmission for the lines are 1/4" NPT. The rear cooling line, requires the special fitting (i.e. Sonnax fitting), for proper fluid flow.

I'm leaning towards using hard lines instead of braided stainless.

The Sonnax fitting has a 1/2" 20 thread inverted flare female fitting for the rear. The front fitting, on the trans, is 1/4 NPT (I believe - not positive).

It seems that finding the hard line plumbing components is easier if I stick to NPT. Will NPT seal well enough? Should I use teflon tape on all NPT connections?

Or, should I try to make as many of the connections using inverted flare type connections for better seals?

As you were told, plumbing with braided line is easier than with hard line but the hard line looks fantastic when done. Do not use teflon tape as a sealing agent because it can send pieces where you do not need them. Use some sort of teflon liquid/paste. If you still want to use hard line use AN fittings (sleeve and nut), 37 degree flare not compatable with 45 degree flares, inverted flares. You will need to get a 37 degree flaring tool to do this. It is strong and easy to use. Let me know if you need more help.