1995-1998 s14 240sx infamous cracked fuel tank

[HellaSlowAndOld]

If you own an s14, I'm sure you've heard about the cracking of the fuel tanks. We find threads as early as 2004 on 240sxforums.com, around 2010 here on zilvia, on nicoclub.com, on reddit etc. Almost every post/thread states its on the USDM passenger side strap, facing the engine bay. AND almost every image found online look nearly identical, its either one crack or 2 cracks almost side by side. location of the crack(s) are to the outside of the passenger side strap by the fuel tank strap pin.

the tank in my s14 cracked 2 months ago so I started my voyage...

OEM fuel tanks were discontinued around 2014 or so. Used tanks rang from $800-$1700. Going fuel cell is an option for some but being in California there are no smog legal fuel cells. And yes, some of us like me, want to keep our cars still street cars, preserve the s14 etc. Others are saying that Nissan used cheap plastic to make the tanks which results in rott/drying up of the plastic causing the crack(s). Plastic welding seems to be out of the question, patching the crack(s) seem to be a temporary fix for most.

The part number for the s14 fuel tank is 17202-15U51. The Nissan skyline r33 GTS-T and the Nissan Laurel C34 use the same tank. (https://www.nengun.com/oem/nissan/17202-15u51) So I googled to see what the r33 guys and C34 guys are doing regarding their cracked tanks. And I found nothing. So this entire time, could it be that the s14 passenger side fuel tank strap is just too tight from the factory? Or possibly too short? Causing the s14 gas tanks to create stress cracks over time only in that spot? Could simple adding ~3 washers to the fuel tank strap bolt help to save our tanks from cracking?

[FaLKoN240]

There's one for sale by me locally in Temecula.

I replaced my gas tank twice before I found a good one that didn't leak.

[mav1178]

Originally Posted by HellaSlowAndOld

The part number for the s14 fuel tank is 17202-15U51.

there were 3, actually. 2 were relevant for the US market depending on which S14 you had

https://zilvia.net/f/showpost.php?p=...3&postcount=28

[AKADriver]

The R33 and C34 use the same strap, too, I'd think. If I had to guess there just aren't as many English speakers driving those cars, and I also don't know if the JDM cars would trip a fault for a small evap leak. I just googled "R33 fuel tank leak" and got tons of results from Australia complaining of leaky tanks.

Has anyone tried to use an S15, R34 GT-T, C35 tank? The dimensions and evap fittings look the same, the only difference I've read about so far is that you may need to use an S15/R34/C35 pump/bracket/hanger assembly. Not sure if that tank is still available new and even if so likely just a temp solution until that tank becomes rare too, but who knows, maybe they improved the part.

Edit: nope, it's literally the exact same 17202-15U00 as the US S14 OBD2 cars in the S15/ER34/C35, haha. Welp.

[HellaSlowAndOld]

Originally Posted by mav1178

there were 3, actually. 2 were relevant for the US market depending on which S14 you had

https://zilvia.net/f/showpost.php?p=...3&postcount=28

gotcha, thanks!

[HellaSlowAndOld]

Originally Posted by AKADriver

The R33 and C34 use the same strap, too, I'd think. If I had to guess there just aren't as many English speakers driving those cars, and I also don't know if the JDM cars would trip a fault for a small evap leak. I just googled "R33 fuel tank leak" and got tons of results from Australia complaining of leaky tanks.

Has anyone tried to use an S15, R34 GT-T, C35 tank? The dimensions and evap fittings look the same, the only difference I've read about so far is that you may need to use an S15/R34/C35 pump/bracket/hanger assembly. Not sure if that tank is still available new and even if so likely just a temp solution until that tank becomes rare too, but who knows, maybe they improved the part.

Edit: nope, it's literally the exact same 17202-15U00 as the US S14 OBD2 cars in the S15/ER34/C35, haha. Welp.

when i googled r33 tanks, i also see a bunch of results, but non pertaining too cracked tank itself. A few threads about tanks splitting at the seams but no cracked, but i am kinda retarded (alex jones here) so I might be looking in the wrong spots

using google translate, i also googled "日産 ローレル C34 燃料タンク割れ" and "日産 スカイライン R33 燃料タンク割れ" I understand that Japanese have different dialects, so google might be giving me the wrong wording. but still nothing really popped out. s15 tanks seem to also be cracking at the seams. ill look more into it a little later

[jr_ss]

Originally Posted by HellaSlowAndOld

when i googled r33 tanks, i also see a bunch of results, but non pertaining too cracked tank itself. A few threads about tanks splitting at the seams but no cracked, but i am kinda retarded (alex jones here) so I might be looking in the wrong spots

using google translate, i also googled "日産 ローレル C34 燃料タンク割れ" and "日産 スカイライン R33 燃料タンク割れ" I understand that Japanese have different dialects, so google might be giving me the wrong wording. but still nothing really popped out. s15 tanks seem to also be cracking at the seams. ill look more into it a little later

It could be climate based too. The rate of expansion and contraction varies nationally and global based on the climate zone you live in. Most of the people seeing tank cracking are in arid climates or see extremely drastic changes annually. Perhaps this is more likely the case, than a strap too tight?

[CrimsonRockett]

Originally Posted by jr_ss

It could be climate based too. The rate of expansion and contraction varies nationally and global based on the climate zone you live in. Most of the people seeing tank cracking are in arid climates or see extremely drastic changes annually. Perhaps this is more likely the case, than a strap too tight?

That could be part of it.

I've easily sold over a dozen S14 fuel tanks within the last year and it's one of the highest demand parts along with S14 window switches and OEM S14 Kouki front end pieces.

We've also had some pretty severe heat waves and droughts. I'm sure the higher temperatures in California have caused pressure build ups in S14's sitting causing them to eventually crack and fail.

I'm surprised no one has focused on a stamped steel version of this tank knowing how many Nissan's share the same model/design. That would be an easy 5000+ units sold considering the demand worldwide and the growing number of restorations. Hell, I would immediately switch over and never worry about that tank again.

[AKADriver]

I think the complex shape might make steel very hard to do (which is why the factory did blow molded plastic). There are fabricators that can do odd shaped aluminum cells like that but it's out of league of most of us probably.

I could be wrong, though. The WC34 Stagea kept the tank aft of the axle but went plastic at the same time so maybe it was just done for weight or cost.

Off the topic but the whole thing has me imagining how cool it would be to build a cannonball run style S14 or R33 with an additional S13/R32 tank mounted aft of the axle...

[Kingtal0n]

My original 95' tank was fine until I went over some really rough roads out in the middle of nowhere. I took the car wayy out to no mans land for some test and tune and found the worst possible road I've ever seen, it really rattled the car up. Came back and smelled fuel... uh oh. The crack location was standard but I have a feeling if I never went over that rough road it would still be fine. Now I just keep a spare tank handy and reinforce them with sports tape, glued using HDPE adhesive using proper prep and heating. And add padding to the straps using cloth and undercoating. The metal strap on plastic just seems like a terrible idea in the first place, I can't believe they did it like that.

[irish_idiot]

The s14 I bought I bought from a grandpa who took really good care of the car, the fuel tank was perfectly fine in their ownership until my three months into using it as a daily was when I started having this gas leak problem. It cracked along the passenger side where the strap goes? I think the small vibrations and bumps in the road causes it to crack.

I initially took the tank to San Marcos plastics to have it plastic welded but the "patch" that was done started leaking again after 3 weeks of driving it normally.

One thing I did notice is in Cali climate as of late, during extreme weather changes such as really cold to hot during the day would cause further stress, because during the entire time that it was cold in the winter I had 0 problems, but as soon as it got warmer and going through a heatwave suddenly I was dripping gasoline along the seam.

From my own observations and experience of this headache it seems to be:

- Heat, or drastic weather changes
- Vibrations in the road
- Also 25 years old

I ended up running a fuel cell because I didn't want another headache with having to take off the subframe over and over again to remove the tank, sucks that Nissan decided to discontinue this part.

[HellaSlowAndOld]

Luckily I found a used tank locally that was very fairly priced. I noticed that the passenger side strap had a much sharper turn vs drivers. And since the strap is shaped like the Nike swoosh, tightening the bolt side, it seems the strap tightens a lot tighter at the turn vs rest of strap. So I added 5 washers between the strap and chassis. My theory is that the shortened distance created via the washers will help take some of that tension off the strap where it turns.


https://imgur.com/gallery/43R6gGQ

I also took Fitted Life's recommendation and add this foam padding from his video https://youtu.be/zAQGxsJIz80

https://imgur.com/gallery/4TElX2D



Since I got 50ft of the padding straps and when looking underneath the chassis where the tank butts up, there was a ton of rubbing scratches. I used the excess padding straps and add them too the tank. Sure it might look retarded but why not try it.

https://imgur.com/gallery/yQQS06P



I currently have GKtech's poly subframe bushings installed which pushes the subframe 10mm closer to the chassis. Everything clears with the "looser" tank installed. I'm going to fill the tank up 1/2 full, check if any movement in tank. If not, fill full and check again. If everything looks fine I'll check later after some mileage.

[HellaSlowAndOld]

[FRpilot]

Originally Posted by Kingtal0n

My original 95' tank was fine until I went over some really rough roads out in the middle of nowhere. I took the car wayy out to no mans land for some test and tune and found the worst possible road I've ever seen, it really rattled the car up. Came back and smelled fuel... uh oh. The crack location was standard but I have a feeling if I never went over that rough road it would still be fine.

That's kind of in line with what I was thinking a while ago about bumpy and stiff suspension possibly not being good for these fragile gas tanks. My S14 is on Tein Flex, which is relatively soft, but there softer suspension options out there or I can even get something like Fortune Auto or Feal and have them spec'ed even softer. I also considered taking my solid subframe spacers out and I have aftermarket RUCAs too, but it's kind of extreme to replace those with oem arms and bushings since I don't think spherical bearings are that bad and the camber adjustability is convenient. Mainly the subframe bushings and coilovers/strut & spring assemblies, so solid subframe bushings are out of the question. I'll probably just replace the subframe and all other stock arm bushings with oem or Nismo or aftermarket oem rubber replacements if I can't find either when the time comes. You mentioned padding between the straps and plastic tank, which seems like a good idea too.

Interesting that in the last week or so, there have been tons of posts and talk about s14 fuel tanks in the various fb groups and two recent threads popping up on Zilvia. I guess it's around the time with these cars being over 25 yrs old now.

[mav1178]

Any part can be made tomorrow

Finding the first 20 or even 100 customers is easy

Finding the next 100 is infinitely harder

I would know… I have trouble selling some of my parts, believe it or not. And mine are as rare as you can get…

[HellaSlowAndOld]

Originally Posted by mav1178

Any part can be made tomorrow

Finding the first 20 or even 100 customers is easy

Finding the next 100 is infinitely harder

I would know? I have trouble selling some of my parts, believe it or not. And mine are as rare as you can get?

I've talked to a few people via facebook that where trying the reproduce the s14 fuel tank, and they pretty much said the same.

[HellaSlowAndOld]

I've put roughly 200 miles since the new tank, no issues of yet. Everything seems to be holding just fine with the looser fuel tank straps. No added noises or vibrations with full tank.

https://imgur.com/a/2K64mLH

[ka24det1995]

SpinWelding is a great fix for cracked HDPE tanks.
Hello guys, it's been a long time since I perused these forums.
Buckle up, here's the long-winded explanation for my confident solution. My '95 240 SX tank split or cracked in 2010 just as typically described. Researching and finding no adequate solution, I pushed off working on it. I also knew the fix would involve dropping the sub frame and take quite a lot of time. I exaggerated the amount of effort it would take in my head, so, I parked the car in the shed. (It had never been my primary driver). After 12 years and my son nearing driving age, the repair was overdue. I began the repair in August 2022. Five weeks later, I had my first failed attempt at plastic welding (heat gun and special iron). After 10 days with 10 gallons in the tank, the gas leached its way through the poor weld. Building on what I learned, I tried again, upping my game. HDPE melts at 285?F. I had the tank and new HDPE donor sheet up to 400?F with 2 heat guns. The plastic got super soft but never really melted. The second attempt was much better, but I suspicioned I had a cold weld. I figured that if I could peel off the new donor sheet, gas would eventually leak. Indeed, about half the repair area could be coerced to peel away. So, the second attempt failed in my mind. I removed all the HDPE donor plastic with wire wheel on a 4" high speed grinder, even the other half area that seemed tight. Time to use plan C, the spin welding recommendation from a friend who has always provided solid recommendations. I bought a $40 bit/tool from spinwelding.com and 100 HDPE 0.875? diameter patches ($10). Borrowed friend's wood working router and proceeded to correct the original crack (and 2 failed repairs). It was far easier than everything I had been trying to this point and worked so well that I have no doubt that the problem is behind me for good. I was originally concerned with the irregular/contoured surface, but it turned out to be no issue, especially since I used the smallest diameter patch (30B).
The root cause for these 240SX cracks is a design flaw (in my view as a Mechanical Engineer). [The study of] Statics would reveal that the tensile force in the metal strap is too high for how it bends sharply around the front of the tank. Some people have used some sort of cushion between the strap and tank to reduce chance of reoccurrence. Not this guy. Doing so would increase the squeeze on the tank if you bottomed out the fastener because you have effectively made the strap shorter. My solution? Only tighten the strap's bolt until you can't jiggle/move the empty tank. Maybe the back side of the tank will sag when full of fuel, that doesn't bother me in the least. The bolt itself is bound up like it has medium thread locker, so I'm not concerned it will back out.
EDIT: Coming up on 2-year anniversary and the tank is holding up great. Someone asked about the patch and driver part numbers. I looked up my invoice. Patch part number is 30B and driver is D-50/350/30

[schassis240]

my freind cracked his fuel tank in his s14...sucks you gotta pull the subframe to install the s14 one...I like the s13 metal ones..stronger and no need drop the subframe

[BoredEE]

Originally Posted by ka24det1995

SpinWelding is a great fix for cracked HDPE tanks.
Hello guys, it?s been along time since I perused these forums.
Buckle up, here?s the long winded explanation for my confident solution. My ?95 240 SX tank split or cracked in 2010 just as typically described. Researching and finding no adequate solution, I pushed off working on it. I also knew the fix would involve dropping the sub frame and take quite alot of time. I exaggerated the amount of effort it would take in my head, so, I parked the car in the shed. (It had never been my primary driver). After 12 years and my son nearing driving age, the repair was overdue. I began the repair in August 2022. Five weeks later, I had my first failed attempt at plastic welding (heat gun and special iron). After 10 days with 10 gallons in the tank, the gas leached its way through the poor weld. Building on what I learned, I tried again, upping my game. HDPE melts at 285?F. I had the tank and new HDPE donor sheet up to 400?F with 2 heat guns. The plastic got super soft but never really melted. The second attempt was much better but I suspicioned I had a cold weld. I figured that if I could peel off the new donor sheet, gas would eventually leak. Indeed, about half the repair area could be coerced to peel away. So the second attempt failed in my mind. I removed all the HDPE donor plastic with wire wheel on a 4? high speed grinder, even the other half area that seemed tight. Time to use plan C, the spin welding recommendation from a friend who has always provided solid recommendations. I bought a $40 ?bit?/tool from spinwelding.com and 100 HDPE 0.875? diameter patches ($10). Borrowed friend?s wood working router, and proceeded to correct the original crack (and 2 failed repairs). It was far easier than everything I had been trying to this point and worked so well that I have no doubt that the problem is behind me for good. I was originally concerned with the irregular/contoured surface but it turned out to be no issue, especially since I used the smallest diameter patch.
The root cause for these 240SX cracks is a design flaw (in my view as a Mechanical Engineer). [The study of] Statics would reveal that the tensile force in the metal strap is too high for how it bends sharply around the front of the tank. Some people have used some sort of cushion between the strap and tank to reduce chance of reoccurrence. Not this guy. Doing so would increase the squeeze on the tank if you bottomed out the fastener because you have effectively made the strap shorter. My solution? Only tighten the strap?s bolt until you can?t jiggle/move the empty tank. Maybe the back side of the tank will sag when full of fuel, that doesn?t bother me in the least. The bolt itself is bound up like it has medium thread locker, so I?m not concerned it will back out.
I?ve got several good pictures and one short video. I just need to figure out how to put them here.

I just want to confirm you went with part number 30 or 30B for the black version from spinwelding.com


Is there a driver tool part number? Oddly the website doesn't seem to list tooling parts.



I'm imagining this is something you'd be best to order over the phone with this company.

[AKADriver]

Originally Posted by schassis240

my freind cracked his fuel tank in his s14...sucks you gotta pull the subframe to install the s14 one...I like the s13 metal ones..stronger and no need drop the subframe

I've kind of wondered if an S13 tank setup would fit in some of these cars.

I mentioned this in a prior comment but the WC34 (Stagea) retained the S13/R32/C33 tank location even though the rest of the chassis is updated similarly to the S14/R33/C34. Mostly so it can have a flatter load floor behind the seats rather than the fuel tank hump between the rear strut towers that the other cars have. It's actually a plastic tank in the WC34 but the same piece was also used in the BNR32 GT-R... anyone know if R32 GT-Rs have tank cracking problems?

[CrimsonRockett]

Originally Posted by AKADriver

I've kind of wondered if an S13 tank setup would fit in some of these cars.

I mentioned this in a prior comment but the WC34 (Stagea) retained the S13/R32/C33 tank location even though the rest of the chassis is updated similarly to the S14/R33/C34. Mostly so it can have a flatter load floor behind the seats rather than the fuel tank hump between the rear strut towers that the other cars have. It's actually a plastic tank in the WC34 but the same piece was also used in the BNR32 GT-R... anyone know if R32 GT-Rs have tank cracking problems?

S13 or any other metal fuel tank really. As long as the capacity remains reasonable, I would be more than happy to modify the floor pan by the rear seats to accommodate a new design.

Another thing I've wondered is weight distribution. Rear seat floor pan or trunk floor pan sections wouldn't be overly difficult to redesign for a new fuel tank. A filler neck could be made to retain the same door location.

I would much rather switch to an S13 or similar fuel tank design over the S14. Out of all the S13's I've owned, only a handful have had fuel leak issues and 95% of them were from being punctured while bottoming out or backing into something. The rest had small leaks from the O-rings and were all easily resolved.

[HellaSlowAndOld]

12/6/2023 update

Its been a over a year now since I replaced the fuel tank and spaced out the gas tank traps via washers. No issues as of yet. I legitimately daily the s14, its on HKS hyper S coilovers and on 55 series tires, I believe that helps too.

[TheVinylKingz]

Originally Posted by HellaSlowAndOld

12/6/2023 update

Its been a over a year now since I replaced the fuel tank and spaced out the gas tank traps via washers. No issues as of yet. I legitimately daily the s14, its on HKS hyper S coilovers and on 55 series tires, I believe that helps too.

Post some pics please of your work. Thanks for the update!!

[Rosdikolaus58]

Climate greenleafguru could also be a factor. The rate of expansion and contraction varies nationally and globally based on the climate zone you live in. Most people experiencing tank cracking are in arid climates or areas with extreme annual temperature changes. It's possible that herbalhighsociety this is more likely the cause than a strap being too tight.

[ka24det1995]

Originally Posted by BoredEE

I just want to confirm you went with part number 30 or 30B for the black version from spinwelding.com


Is there a driver tool part number? Oddly the website doesn't seem to list tooling parts.



I'm imagining this is something you'd be best to order over the phone with this company.

Yes, 30B is the patch. Driver tool part number D-50/350/30

[HellaSlowAndOld]

8/9/2024 update

still driving the 240 daily, stepped up the wheels from 16s to 17s with 45 series front and 40 series rear. No issues to report as of yet.

[bekeanloinse23]

Originally Posted by HellaSlowAndOld

12/6/2023 update

Its been a over a year now since I replaced the fuel tank and spaced out the gas tank traps via washers. No issues as of subway surfers yet. I legitimately daily the s14, its on HKS hyper S coilovers and on 55 series tires, I believe that helps too.

Thanks for updating!