Leaky Gas Tank

[street_127]

Hey guys I have a gas leak! After a drive it leaks but below a half a tank it tends not to leak anymore. I believe its coming out the top through the filler when it moves around but I wanted to see if anyone has had this problem before and if it is common. My car is an 89 325i. Thanks

[SlamedIAm]

Replace the o-ring around the top of the pump and check to see if it continues.

[street_127]

I believe that this is the leaking line. There are three lines that run along the bottom of the car and this is the middle one. It turns to rubber and goes upward into the edge of the tank (Its about halfway up the tank which would explain why I can't put more than a half a tank in without dumping gas all over)

Please, someone help me out.

[street_127]

I need to know what line this is and the process of replacing it because it looks as if there is a nipple that pushes into the tank or something and its real loose.

Also, I checked the top of the tank through the rear seat and it doesn't look like I have any leaks there.

[SlamedIAm]

I believe that this is the leaking line. There are three lines that run along the bottom of the car and this is the middle one. It turns to rubber and goes upward into the edge of the tank (Its about halfway up the tank which would explain why I can't put more than a half a tank in without dumping gas all over)

Please, someone help me out.

I had the exact same issue of not being able to fill up more than half a tank without spilling at it was that o-ring.

The picture you've posted is of the fuel feed line. It's goes through that grommet and across the top of the tank but connecting to the pump with a short piece of fuel line. There is no reason why this should be effected by your fuel level as it is not entering the tank there.

Again, I suggest you replace the fuel pump o-ring first as it is a known source of the exact issue you have.

[street_127]

So I pulled that o ring out and cleaned the area, lubed up the o ring and put it back in. Filled up to 3/4 tank and drove around some windy roads, it still leaks a lot. I think I am just going to pull the tank and start fresh with lines and anything rusty unless there are other suggestions.

But thank you slamediam for your help, I appreciate it!

[SlamedIAm]

So I pulled that o ring out and cleaned the area, lubed up the o ring and put it back in. Filled up to 3/4 tank and drove around some windy roads, it still leaks a lot. I think I am just going to pull the tank and start fresh with lines and anything rusty unless there are other suggestions.

But thank you slamediam for your help, I appreciate it!

If you don't want to pull the tank just yet you could go ahead and replace the lengths of fuel line connecting the pump to the semi-hard lines across the top of the fuel tank. These are likely old, brittle, and due to be replaced anyway.

If you do want to go the tank route I'd be more than happy to answer any questions as I've done it twice in about 18 months.

[street_127]

If you don't want to pull the tank just yet you could go ahead and replace the lengths of fuel line connecting the pump to the semi-hard lines across the top of the fuel tank. These are likely old, brittle, and due to be replaced anyway.

If you do want to go the tank route I'd be more than happy to answer any questions as I've done it twice in about 18 months.

Would you be able to tell me the general process as to removing the tank? I know the exhaust and drive shaft have to drop but that's it. Thank you

[M-technik-3]

They rust along the seam replace tank with a new one and be done with it.

[roguetoaster]

Would you be able to tell me the general process as to removing the tank? I know the exhaust and drive shaft have to drop but that's it. Thank you

Yep, the DS and exhaust first. Then label the lines above and below and remove them. Remove the tank filler tube. After that you have 4 or maybe 5 main tank retaining bolts (one might be a nut). I don't mean to deter you at all, but it's a fair ordeal. Get someone to give you a hand with the R&R or your will struggle mightily.

[street_127]

Thanks guys. I will definitely have help throughout the process. I will probably end up replacing the tank and all or most of the lines so I won't have to worry about it again.

Genuine BMW tanks are really pricy so I looked into my options and JC Whitney has one for $189 and then another %10 off.

heres the link http://www.jcwhitney.com/replacement...17266y1989g2j1

Any opinions on the tank?

[SlamedIAm]

Would you be able to tell me the general process as to removing the tank? I know the exhaust and drive shaft have to drop but that's it. Thank you

What the other posters have stated so far is pretty much how it goes but I'll explain what I remember of it.

First off definitely grab a buddy and buy him some beer for his trouble. Nothing is really that difficult or heavy (and I'm a small guy) it's just some large objects.

Start by jacking the car up and getting plenty of jack stands under it. Drop the exhaust, heat shields, and driveshaft. If anything on your transmission is leaking now is a good time to do it or replace any shifter bushings. You'll need 6 new locknuts from the guibo. Also a good time to do guibo/CSB if they aren't fairly new. You'll need another 4 locknuts for where the driveshaft connects to the diff. I believe they're the same ones as the guibo. Not a bad opportunity to do trans/diff fluid while you're at this.

Remove the metal covers over the fuel filter and fuel tank. Remove the fuel filter and disconnect the soft lines from it. Labeling them is a good idea, and replacing them is too if they're original. I'd suggest using new hose clamps.

Remove the fuel filler hose from the back of the tank by the rear passenger wheel. Under the backseat remove both covers and disconnect the pump/fuel hoses/vent hose, and both fuel senders. Labeling lines will make installation easier.

Replacing the filler hose and any soft lines isn't a bad idea. The vent hoses running into the passenger rear wheel well are a pain in the ass so you probably won't want to bother unless something is damaged. Be extremely careful of those as you lift your new tank in as they're easy to pinch (and my buddy did so I had the joy of swapping them out).

When you get to the tank it's 5 (I think) bolts. You might have to bang it from the top or you might not. Definitely drain any fuel before hand or it's going to be extremely heavy and probably spill on you. Don't forget to swap the grommets and heat shield brackets from your old tank to the new one.

Installation is reverse.

I may have left something out so feel free to PM me or ask any other questions.

[Cinnabar325is]

Thanks guys. I will definitely have help throughout the process. I will probably end up replacing the tank and all or most of the lines so I won't have to worry about it again.

Genuine BMW tanks are really pricy so I looked into my options and JC Whitney has one for $189 and then another %10 off.

heres the link http://www.jcwhitney.com/replacement...17266y1989g2j1

Any opinions on the tank?

There's probably a good chance that hard metal pipe that runs across the top of the tank (and is welded to the tank) is rusted. That's where mine rusted through because of salt water/brine setting on top of the tank from the winter roads. And seeing that you're in CT, you could have the same issue.

I replaced my tank with that same tank you linked from JC Whitney and I paid $250 for it. Dang it! It's definitely the way to go, not quite the same quality as OEM, but pretty good and it fits exactly like it should. No problem there. I painted it black, though.

[street_127]

There's probably a good chance that hard metal pipe that runs across the top of the tank (and is welded to the tank) is rusted. That's where mine rusted through because of salt water/brine setting on top of the tank from the winter roads. And seeing that you're in CT, you could have the same issue.

I replaced my tank with that same tank you linked from JC Whitney and I paid $250 for it. Dang it! It's definitely the way to go, not quite the same quality as OEM, but pretty good and it fits exactly like it should. No problem there. I painted it black, though.

I paid $188 total for the tank and a mann fuel filter! The %10 off really helped!

[street_127]

On Friday I took the plunge and started to drop everything. I dropped the entire exhaust including headers (I installed aftermarket), driveshaft, and all heat shields (I painted them all). Saturday I dropped the tank and installed the new one, installed driveshaft and entire exhaust. Car wouldn't start so I went back to work this morning and found a fuel line that I had switched. Now it runs but I have a terrible header leak! Going to bring it to a shop this week and have them do the headers and weld the new section of exhaust that I installed. Thank you everyone for your help and advice!

Edit: Also, the welded line on top of the tank rusted through and was definitely the source of my leak!