GTSBoy

Because an o-ring is a cushion that prevents the male fitting from pulling up hard on the external seat of the connection, unless the o-ring is deformed beyond intended design in that conical seat. That seat is not designed for an o-ring. AN fittings do not look like that. Parallel threads are of course completely normal on collar type fluid couplings that have conical metal on metal seats. This is not the same situation.

CFL backlight probably gone to the crapper.

Well, it kinda is. They've used a thread that looks about the same as a 1/8" pipe thread, but isn't. Then you either have to use their fitting or go out of your way to get a fitting that has that thread on it, which has got to be about 100x more difficult than just getting something with a 1/8". But then it wouldn't tighten up. You'd be relying on a threadlocking compound to stop the fitting backing out.

Yes, and look at the conical seat on that port. It is clearly meant to work with a bespoke fitting that has that cone on it. Seems silly, when everybody else would just use a 1/8" NPT or BSP parallel in there, with a tapered fitting. I mean, good on the yanks for doing something, anything, in metric. But dumbo points for using a metric bolt thread for a f**king plumbing fitting.

There's not really any such thing as "metric pipe threads". When we're talking about screw in fittings, and elbows and Tees that go onto pipe, etc etc, there is really only 2 dominant threads. BSP and NPT. The Yanks, the oil & gas industry and a few others are stuck on NPT. The rest of the world pretty much uses BSP. The Europeans call BSP threads by other names though. If you see a German company describing a threaded port or stub on their equipment, they will call it G1/2" or G15 (same thing). And there are other variations on the theme. M8 is a bolt thread specification. It is really not relevant to "plumbing" fittings. People don't use metric bolt thread forms for tapered male into female sealing threads. They may well use metric bolt thread forms on collars of fittings that use seats to seal (like Swagelok or other similar pneumatic or hydraulic fittings) but they are just as likely to be imperial/American or totally custom in those systems, seeing as they are usually proprietary anyway.

I'd be very willing to try a HGT 6 speed.

But we don't think of them as a Corvette engine. They were a family car engine here. They're lying around in piles. Much better idea than trying to upgrade to any RB option.

Just one more thing on the list of sketchy looking things with that car.

Yes. Basically the same thing. No, because AWD. Why bother? Break the gearbox, then replace engine and gearbox with LS1 & T56.

The Neo is the smart choice.

The GTR manual is pretty much suitable for the GTSt. Doesn't cover 2WD stuff obviously, but it covers GTS4, which is RB20DET, so you get pretty much all of the GTSt stuff you need except gearbox. GTS uses a flimsy gearbox related to the 4 cylinder boxes. GTSt is basically the same box. These are tiny boxes compared to the big tough RB25DET box. The RB25DET box is basically the same as the front half of the GTR box. The Z32 boxes are related to the RB25DEt and GTR boxes, but obviously with VG bellhousing (which is the whole front half of the casing). You cannot mix and match anything from small gearboxes to big ones. Some (many) of the parts from big boxes go back and forth. AWD boxes are obviously different in many ways. They have a transfer case, so the output end is different, the shifter is different, the mounts are different. All of this information is available on here in spades! Just search. It's been >20 years since this forum started.

Well, none of us want diesel.

Same manufacturer does not imply same manufacturing techniques, machines, processes, QA/QC rules on tool inspection and replacement (CNC machines are not magical devices - they require a f**kton of expert care and feeding), etc etc. To a large extent you can set your pricepoint and tailor the quality of the manufacture to suit.

It was a joke. This is a Skyline forum. We know nothing about BMW 4 cyl diesels and how their compound turbo systems work. So we recommend suitable Skyline related suggestions.

The RB25DET gearbox is big and strong. Any box that came behind ANY RB20 is not. They do not last long when pushed by a 25.

Is it a Tesla?

I'm pretty certain that no-one here has the slightest idea how a compound turbo system on a random BMW diesel 4cyl engine is supposed to work, let alone how to diagnose a mystery problem with one.

Spray carby cleaner at possible leak spots. If the idle drops, you found a leak. You can also pressure test the intake tract (up to the TB anyway).

It couldn't be the other thing, could it?

And long may such automotive hypocrisy continue. The last thing we should be doing is dropping the old cars because the new cars are simply faster. Why would anyone continue to play with the Historics, a la Goodwood, otherwise?! I am dismayed with myself for not keeping the wreck of my HG, because whilst it was proper f**ked in the late 80s when I binned it, it was actually quite repairable. I am dismayed with myself for putting my HQ Monaro into harm's way and letting it be stolen. I occasionally kick myself for not fixing my VC Commode when I bought my ALFA, and then selling it for a pittance. I continually kick myself for offloading the ALFA when I bought the Skyline. I bought the R32 for very good reasons in terms of what it would cost me to make the ALFA perform as well as the already turbod, already 4 pot braked, etc R32.....but I still miss the way the 116 chassis handles, and that car would be worth 5x what I got for it by now. I simply cannot contemplate paying as much money for a new car that would actually not be a soulless transport appliance. $100k is much better spent elsewhere. So I will never part with the R32 and never stop dailying it, unless there is no option.

yes.

Have you fixed the vacuum leak?

FFS! How about applying a little bit of science?

The answer is heaps is pulled out. Subarus from the 90s were really good. Well engineered, good quality components. By 2010 the rot had started to set in and they had so many common problems. Head gaskets at 130000km. Leaking seals. Shit suspension/body bushes by 30,000. Etc. Bad electronics (coils, ignitors, etc). Nissans became Renaults and all sounded worse than an SR20 or 4G63 (which are both about as bad as a 4cyl can get). All BMWs from the last 20 years have time bombs built into the engine and the gearbox and the electronics. Same with Audis. Merc used to be pinnacle engineering and they are now riddled with cheap components and poor engineering choices. This is not to mention the lack on investment in actually achieving emissions standards and just cheating the tests! I'm look at Ze Chermans here in particular.

Measure the resistance of the sensor when cold and when at operating temperature and compare with the KNOWN temperature-resistance characteristic of that sensor. Job done.