3.2 coolant manifold corroded fitting, fixed !

[Eric B]

I am going through all my parts before I start to re assemble my 3.2 dohc / dohc hybrid. I came across this coolant pipe Y transition to rubber line. The pressed in steel nipple has corroded all the way through. Any ideas ? I am thinking of cutting the steel part flush then tapping 1/2 or 3/4 NPT threads , and installing a threaded brass nipple with a barbed end . There is about 4 mm of material to work with , and I can tap down at least 1/2 inch on the manifold..... Thanks in advance

[lucamax]

I would try to remove the damaged tube before tapping with the available fine thread.
If the damaged pipe is pressed, if you expand the aluminum with heat you should be able to pull it out
Or drill it if you have a precision drill column.

[Eric B]

I believe I can flush cut the tube , carefully split it within the raised boss , and collapse it . The boss appears to be about 4 mm thick , and I can tap 12 to 14mm in depth. I may go standard pipe thread ( NPT) but the jump between 1/2" and 3/4" is quite a bit. I could also warm the manifold in the oven - like 200 degress, and freeze a new tube, then press them together. I have access to liquid nitrogen. The cooling system is under pressure , about 14 lbs , not much , but it cannot leak. I own a mill , presses , and have access to a machine shop , but I am wondering if anyone else has completed this repair , rather than simply buying another one .... of which there is a dwindling supply of new ones.

[Eric B]

After some careful measurements , I was able to split and collapse the pressed in tube. The 3/4” NPT tap seemed to large at first, but it is perfect. I ran the threads down as far as possible. If you try this , insure that your manifold is square and level clamped , as you don’t need the tap to cut at an angle.

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It will bind and possibly crack the manifold. Say no to crack. I drilled and tapped the adjacent water tube with a 3/8 fine thread.

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The 3/4” and 3/8” threaded brass fittings are in stock at every hardware store.
I was not planning on using tape to seal the threads, but I still might use some sort of gloop. Happy to save a good part.

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[93trooperpooper]

i hardly use pipe tape anymore.....i use permatex thread sealant on all my air/ water/ oil fittings. i have seen thread tape wrapped around water pump impellers, and thread tape stuck to the suction side of pump screens aka oil pumps