Blew the stainless-steel fuel line.

[TheMarkedOne]

I thought this would be an interesting post. But I have a very modified car, and I regularly go out racing on the weekends. On the way back I smelled some E85 and popped the hood. Check this out! Guess the OEM stainless steel line cannot handle the prolonged pressure overtime. Will need to find an aftermarket replacement that can handle it. But for now, I replaced it with an OEM part for 150 bucks. Part number is 17520-6GP0A if anyone is interested but was told by the dealer to probably buy a few spares before any aftermarket replacements come about. Glad there was no fire!

Update 3/16/26: On my third line keeps breaking at the same spot on the copper. No aftermarket replacement yet.

 

[RobotAZ]

Looks like the fitting. Buy a Swagelok fitting and it won’t leak, ever. I design natural gas facilities with a lot more pressure than a fuel line and have never heard of a leak.

 

[TheMarkedOne]

When I inspected the old line, it was coming out of the copper seal before fitting. The new line what looks to be a thicker copper seal/copper ring around it. Not sure what happened to the previous one.

 

[bpeckham]

Seems like my stock car may have had a similar problem. https://www.nissanzclub.com/forum/threads/fuel-rail-leakage.9258/

 

[bpeckham]

@TheMarkedOne , to orient myself, your video is with the engine cover removed, and the black cap is the oil filler cap and the driver's side (LHD models) air cleaner is in the lower left of your video. Front of the car is to lower left, is that correct?

 

[KrackaC8]

Please report this to NTSB, stock or not, with two issues on the forum at the moment this could be a wider issue in need of a safety recall (and an improved part from Nissan).

 

[FSUZ33]

@TheMarkedOne , to orient myself, your video is with the engine cover removed, and the black cap is the oil filler cap and the driver's side (LHD models) air cleaner is in the lower left of your video. Front of the car is to lower left, is that correct?

Correct.
If you’re standing in front of the car looking at the engine it’s in front of the oil filler neck, with the fitting that’s leaking on his just To the right. Pretty sure you need to remove the engine cover to see it.

 

[Zplz]

When I inspected the old line, it was coming out of the copper seal before fitting. The new line what looks to be a thicker copper seal/copper ring around it. Not sure what happened to the previous one.

Thanks for posting the video. It definitely could have turned into a dramatic "flame thrower." I wonder if it was faulty manufacturing versus a bad design. Hopefully, it's not something involving all Z fuel lines. However, your description of the new line could indicate a design mod, unless they really screwed-up in production. You'd hope Nissan would have done a notification for the Z, especially if they actually changed the design for a part with such safety critical implications but even a manufacturing defect should have rung some bells. Then, again, they've had a part on the engine for years, the oil solenoid, that could result in totaling the engine if it decides to fail.

Definitely something to be aware of, especially if you start to smell gasoline. Having your Z self-immolate would make for a very bad day.

 

[FSUZ33]

Not sure if the majority or all fail at that spot. Could be a manufacturing defect (crimping that fitting incorrectly. Or an installation defect (twisting the tube/fitting when tightening the nut). Or something else. Regardless, if you install one yourself, m,y advice is to loosely attach all but the screw-on fitting so that you can make sure that fitting lines up. If they're already weak at that spot and you tighten that nut first, moving the rest of that assembly around could put more stress on that joint. Also watch for movement of the tube as you're tightening the nut. You shouldn't see any movement. May even benefit to put a tiny bit of antisieze in the end of the fitting where it swivels against the flare of the tube just to give it a tad more lubrication.

One thing I don't suggest is loosening it to inspect and reattaching. If it's already prone to failure I would say that thing's a one-time-use part. Not cheap, but that thing leaking creates a dangerous situation really quickly.

 

[Zplz]

Not sure if the majority or all fail at that spot. Could be a manufacturing defect (crimping that fitting incorrectly. Or an installation defect (twisting the tube/fitting when tightening the nut). Or something else. Regardless, if you install one yourself, m,y advice is to loosely attach all but the screw-on fitting so that you can make sure that fitting lines up. If they're already weak at that spot and you tighten that nut first, moving the rest of that assembly around could put more stress on that joint. Also watch for movement of the tube as you're tightening the nut. You shouldn't see any movement. May even benefit to put a tiny bit of antisieze in the end of the fitting where it swivels against the flare of the tube just to give it a tad more lubrication.

One thing I don't suggest is loosening it to inspect and reattaching. If it's already prone to failure I would say that thing's a one-time-use part. Not cheap, but that thing leaking creates a dangerous situation really quickly.

All good points. I'll keep an eye on it but I'm not messing with it, for now, as in "don't try fixing it if it's not broken." Maybe someone in Japan was having a ham-fisted, bad Monday during production a few times. I sure hope Nissan and/or the NHTSA keeps an eye on it, too. We shall see.

 

[FSUZ33]

It's in this spot:

 

[G M]

Please report this to NTSB, stock or not, with two issues on the forum at the moment this could be a wider issue in need of a safety recall (and an improved part from Nissan).

You probably meant to say the NHTSA as they are the agency responsible for safety recalls.

Here is the link: https://www.nhtsa.gov/report-a-safety-problem

 

[KrackaC8]

You probably meant to say the NHTSA as they are the agency responsible for safety recalls.

Here is the link: https://www.nhtsa.gov/report-a-safety-problem

Yes, thank you!

 

[TheMarkedOne]

Wanted to update you guys that I’ve replaced this part twice already. I’m now on my third one, and it failed in the exact same spot at the copper again. This time the dealer did the install just to rule out any chance that I caused the issue.

I’ve also seen multiple reports of this happening to other Z cars in my Facebook community. Guys have had theirs blow out in the same location too. What’s concerning is that this seems to happen whether the car is tuned or completely stock.

Honestly, at this point it feels like a major design flaw and a lawsuit waiting to happen. I’m pretty surprised no aftermarket company has stepped up to make a proper upgraded replacement yet.

 

[FSUZ33]

It looks like it goes from that screw on fitting into a distribution block, then splits to the fuel rails, and the fuel rail connections are hose clamps, so I assume there's not a crap-ton of pressure on it...fuel pressure, I guess (60psi?...idk).
It would be possible to fab a quality fitting, but I don't know what's going on in that block (whether it's a straight-through split, or there's something fancy in there).