Fuel Tank Leak

[Stukwon-do]

Filled my 1996 Galant VR-4 with gas and when i got home after about 30 Mins could smell petrol in the garage, looked under the car and sure enough the stuff was pouring out right under the tank on the passenger side, there was about a square meter puddle on the floor. I thought I'd smelt petrol the last time i put a decent amount of gas in but could never see anything but if its got less than about 1/2 a tank full then its fine so naturally I'm gonna assume that its leaking from the tank somewhere around half way(possibly the tank seam). I've searched and found a few people having similar problems:
http://www.clubvr4.com/forum/showthr...Fuel-tank-leak

This one is decribed as the "fuel tank sender seal".. Is that the thing under the steel cover that's screwed down under the back seat..? If so that's not the problem, no petrol here at all. Assuming it is the seam or corrosion or something along those lines, is it fixable or do i need a new tank? Any info/thought appreciated.

[elnevio]

You need to check whether the fuel tank recall has been done on your car, as you may be able to get the remedial work done for free. Look for the 'Check your car's recall status' thread.

There are two fuel pumps. There is the main fuel pump on the driver's side under the back seat, and there is a lift pump on the passenger side, which moves fuel over the hump in the middle of the tank (which is there because of the 4WD running gear). If either of the seals are leaking (the sealing ring(s) may only need slightly tightening), then yes it will usually only show up when the fuel tank is full. To see if it is either of these, you need to remove the screwed-down plates, otherwise you can't see the fuel pump assemblies! They are pretty unmistakeable when you see them, and their design is such that if you have had a leak, some of the petrol pools on top of the assembly. It is a fairly easy check though - you shouldn't be able to move the plastic sealing ring by hand for sure - there have also been the occasional reports of this ring cracking, which means it can't do its job. Furthermore, sometimes the seal itself may not have been reseated properly if the sealing ring has been off.

So yes, I'd be surprised if there is a problem with the fuel tank itself - they're not known for splitting or anything, and I would be looking at the lift pump sealing ring assembly.

[Stukwon-do]

How accurate is this recall status because i got: "4 models such as gear run and [regunamu] (the 4WD car) about the fuel tank" and it says "Work performance being completed"(27/06/2000) is that the direct translation meaning "Completed" or that it is still "Being Completed"?

[wintertidenz]

Are you sure that you haven't drilled any holes through the tank when fitting any cables for a sound system?

[Stukwon-do]

I haven't fitted a sound system. I haven't done anything to this car yet. I've only had it for about 3 weeks and the only sound system mods are different head unit and 2 6x9s on a parcel tray in the back, I don't know why you would be drilling any holes anywhere near the tank to fit them..?

[elnevio]

Yes, that means the recall work has been completed. I'd be looking at the sealing ring on the lift pump assembly now!

[blodeaxe]

there is a lift pump? i dont see it?
On the passenger side all I got is a fuel level sensor

[elnevio]

there is a lift pump? i dont see it?
On the passenger side all I got is a fuel level sensor

What version Legnum do you have? If it is FWD rather than 4WD, then the tank doesn't have a hump in it and doesn't have a lift pump. However, I would have thought that the fuel gauge sensor would still be part of the main pump assembly.


Here's the VR-4 assembly:

VR-4 fuel tank assembly.png

You can clearly see the hump in the middle of the tank. The driver's side fuel pump & gauge assembly is on the upper left of the picture and the passenger side lift pump assembly is to the bottom. The part on both pumps with number 05261 is the seal (aka gasket). The sealing ring is 05102. These parts both appear to be identical to each other.

As a side note, I have noticed that in the top right hand corner of that picture is something I didn't know what it was. Turns out that it is a 'Gauge Unit, Fuel Tank'. I therefore believe this is the sensor for the fuel light on the dash. The one attached to the fuel pump assembly clearly affects the operation of the fuel gauge, which I can vouch for from personal experience!


Anyway, hopefully something among this lot is useful to you!

[blodeaxe]

this is what the diagrams said is in the passenger side of the tank..........no pump just a cone shape fuel level sensor

the fuel line leads to a mesh filter

[elnevio]

Well, on closer inspection, you appear to be correct!


It would appear that the 'lift pump' is powered by the main fuel pump. Wonder what the level sensor is for then? Maybe THAT's the fuel light one?


ANYWAY, regarding the original post, it's still worth checking either of the seals/rings to see if a fuel leak is coming from there.

[Patryn999]

Just be careful removing the ring by hand. Mine cut loose and I ended up with the metal skin burried to the bone in my finger, and had to try and tighten it back up to get my finger out The ol' galant got more than its fair share of blood/sweat and swearing that day.

Yeah, in retrospect it was pretty dumb but hey. Ended up lightly tapping it around with a flat-head screwdriver and a mallet.

[Oggie]

you know i just realised that i too have a gas leak in my legnum gets really badd when i go faster

but seriously... I hope you get it fixed asap.. I had a fuel leak once and it cost me a bucket tonne to get fixed.
4.1 L straight 6 MK IV cortina with a leakign fuel pump.

that reminds me.. checked the fuel pump?

[Stukwon-do]

So how do i get at the seal for the passenger side level sensor? Under the back seat on the passenger side there is no steel cover like there is on the drivers side(for the main pump)?

[blkcar]

I have also developed a seam leak on my fuel tank. Had it all pulled out & had a plastic weld repair done on the seam, after which I pressure tested it twice & everything was fine so I put it back in.
The plastic weld guy would not guarantee the weld on a seam as they are notoriously difficult to repair properly. Anyway once back after just 2 weeks it started to leak again.

As such I'm chasing another tank but I'm really worried that I'll get another dud plus I'm finding them hard to come by.

Does anyone know whether any other more common Mitsu models that share the same fuel tank as the Galant & Legnum?

[Nutter_John]

should not be that hard to find one put a WTB thread on here and on OZvr4