TheTallOne

Daily Driver
Does anyone know the size of the inlet and outlet tubes to the coolant tank from the thermostat housing? I'm rebuilding an '84 FI engine and the larger tube is totally rusted away to nothing, while the smaller tube is functional, but could use attention too. The usual suspects only seem to carry full replacements, so I can't just buy a new tube from them. The bigger one appears to be M19x1.5, but my diameter guessing is not the greatest
 

I asked a similar question a couple of months ago. Hope this helps.
 
The bigger one appears to be M19x1.5, but my diameter guessing is not the greatest
That sounds right for the thread, it's tapered too IIRC - good luck getting it out in one piece 😬 The hose tail is 18mm +swaged end.
 
They are a tapered metric thread.

Are you in the US? I may have the pair as spares. I'll have to look. Probably some pitting, but they were certainly good when I removed them to switch to larger bore fittings .
 

I asked a similar question a couple of months ago. Hope this helps.
Thanks for posting Alex. I thought this topic sounded familiar but could not recall who it was.

I might be misunderstanding things, but all of my thermostat housings have cast-in hose barbs, not threaded (removable) ones. What years had that?
 
Mine have all been cast as well. Last one I did, I zipped off the fittings, tapped the holes for NPT and installed new barbs. Back in business - quick and cheap.

IMG_3749.jpg
 
What size fittings did you use? Did you drill the ports oversize before taping?
Did it awhile back and really don't remember the details. It probably was 1/4 and 3/8 NPT and the barbs are not metric so they are whatever is close to the original hose size. I think the holes were a little over sized, so the tap was not a problem, but the threads were looser than I was comfortable with, so they were liberally coated with JB Weld, screwed in and cured for a day or two. It's been running for awhile now and works fine.
 
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