S14 Fuel Tank Repair

[ixfxi]

Repairing the plastic S14 fuel tank has been a topic that has come up time and time again over the years here on Zilvia and various other forums. Being that I've always owned an S13 and other vehicles with steel tanks, I've never had the need to repair a plastic tank until my recent acquisition of an S14. If money is no issue I highly advise purchasing a new tank. In my case, this restoration project is so vast that I am doing my best to keep a practical budget in order to keep costs from spiraling out of control.

If your tank has a large split it will most likely need to be replaced. My tank had some very small pinhole leaks in the front LH corner, right along the factory plastic welded seam.

For all you novices, this is no easy fix and you will need to go through the extensive procedure of dropping the subframe, emptying the tank and then dropping it. I advise that the tank MUST be empty before attempting this fix.

Once you have emptied the tank, wash it out with water - inside and out. Dry it off and then seal off the tank as best as possible as you will need to pressure test it with compressed air and use soapy water and a brush to locate the leak(s). Locate the leaks and mark them with chalk. The next step is to use a heat gun with an exacto flat razor. I used the flat razor as a putty knife and using direct heat from the heat gun, managed to heat and rework the plastic tank. It took multiple attempts, but eventually I managed to close up and cover all the pin holes. There must have been about 5-6 very small holes, but that was enough for the fuel to seep out of. Here are some photos of the tank and the repaired area. You can see how the OEM seam has been flattened and smoothed.





As of today, new tanks list at $650. Most of the fuel related parts are discontinued. I would highly advise buying a new tank. But, if you are on a tight budget and replacing the tank is NOT an option, hopefully this fix will help you.

Note: I pressure tested the tank and it checked out A-OK.

[Hoffman5982]

I had my tank professionally repair. Put it back in and the car back together. 2 days later I came out to another puddle underneath the car. I dropped the money on a new tank and never looked back. At the time it was about $350-400 and I had to drive 4 hours to pick it up at the closest dealer with one in stock. Hopefully you have better luck

[ixfxi]

Thanks, I hope it works too. I will update with one more thing. Being that this is such a bitch of a job, I wanted to double and triple check my work and noticed one small pin-hole that was really tough to seal. Rather than continue to rework the area, I tried adding some filler plastic. I got pissed off and grabbed one of these removable cable ties (sorry, I dont know the name for this damn thing). Anyway, I worked the area and then melted it in as filler and it really flows well and surprisingly, bonds extremely well to the tank. These cable ties have a much lower melting temperature, but should suffice as filler. Here is a photo of the reworked section:



Good luck!

[Tempo]

I personally had to do this on my s14 last year, got lucky buying a low mileage kouki tank in excellent condition from a member on here. Ixfxi is correct about the work being extensive but if you have dropped your subframe before for bushings you're just a few hoses, clips and a heat shield away from unbolting the tank from there.

You will definitely know when your tank is leaking when you notice caked on crap on your subframe if you keep putting aside the job like it did [emoji28]

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[KAT-PWR]

Shop owner had a vertical crack starting about 2" below the ribbed seam extending up over the top of the tank, dremeled the seam the width of one of those gastank repair patches, epoxied it in. Still not leaking (been like 6 weeks maybe)

Also did it in the car with the tank drooped