S4s turbo coolant ports -thread size?

[Chillidoggy]

Despite them supplying me with the new turbo, the laughingly-termed "customer service department" at Fawlty Turbos had, as expected, "errrr......no idea mate" as what the female thread in in the turbo body might be.

Does anyone know, please?

[Trevsked]

From memory I think they are quite big but not sure if that's metric or imperial. HTH.

Trevor.

[Chillidoggy]

Thanks Trev.

[eeyoreish]

Is the bolt/stud thread size not shown on the parts diagrams (Deroure site etc)? They often are...

[Zolder]

Just checked my parts manual, not much help I'm afraid......

[Chillidoggy]

No, there's no size listed I can see, and I have searched the web extensively, but come up with all kinds of different answers.

The brass fittings look unique, I've never seen anything like them, only shorter block elbows, but the female end fittings are 5/8" UNF, 18 TPI, and the male end is a taper.

I suspect it's 3/8" NPT, but I don't know.

[sailorbob]

I believe they are 3/8-18 NPT but I'm not 100% on that.

[Vulcan Grey]

I don't remember the size, but I replaced them with parts from an American home and garden store... So they are definitely not metric. I think sailorbob is correct.

[sanj]

3/8" NPT. The other end is a standard flare nut.

Edited April 18, 2015 by sanj

[Chillidoggy]

So the turbo body is 3/8" NP, and the brass fitting is 3/8" NPT? Or are they both NPT? I suppose if I get a straight fitting , I could check that.

NPT dies are available, so I could conceivably shorten the brass fitting, and recut the thread if I'm careful.

[sanj]

The female threads in the turbo and the mating male threads on the brass fitting are the same, either NPT or NPTF. If it's damage at the male end of the brass fitting you're dealing with there's no reason I can think of to stop you re-threading it. There is a limit on how short you can make it, however.

[Chillidoggy]

Having done some more thinking, and a bit more research, I've come to the conclusion that the original fitting has to be replaced. They are definitely 3/8" NPT, in case anyone is interested. Or at least they are on my turbo/fitting.

I'm not going to bother shortening and rethreading the brass fitting, it's too much of a pain, because I'd have to machine a taper on the shortened fitting, and to do that I'd have to set it up in a 4-jaw chuck, plus order an NPT die, or set the lathe to thread cut, and it's getting a bit time-consuming.

So I've found, and ordered up, a 90 degree 3/8" NPT elbow which has a 3/8" hose tail. I've ordered some new 3/8" flexy pipe, and hopefully that should solve my problem.