Author Topic: Easiest way to clean a fuel tank..?? (Read 5881 times)

E30J · « **on:** November 28, 2013, 05:13:45 PM »

Well i recently purchased a 91 318is and it had been sitting a while.

Wouldn't start, come to find out the fuel pump and relay are both bad. Pulled the fuel pump and looked down in the tank and everything looks pretty caramelised and rusty.

Is there any solution i can pour in the tank and maybe give it a rinse?? Trying to avoid dropping the whole thing which i think also requires removing the exhaust and drive shaft��

Any help will be appreciated.
Thanks

keflaman · « **Reply #1 on:** November 28, 2013, 07:56:14 PM »

I don't have a lot of personal experience cleaning automobile gas tanks, but if you search the net for something to the effect of "cleaning varnish from gas tanks" you'll get a ton of hits.

A couple of things to consider about the gas tank in our car: The drain plug on the tank isn't very large and there is a crossover tube between the two tank sections. Depending on the amount of debris and rust you have may determine whether or not you have to drop the tank.

DesktopDave · « **Reply #2 on:** November 28, 2013, 09:09:08 PM »

I've tried out chelating rust treatments like Evaporust. They work well, but I'd bet twelve gallons or so would get pretty expensive. It also has trouble with fuel varnish.

I've lined motorcycle fuel tanks with Kreem, but that'd be pricey too. POR-15 has a great motorcycle kit, but I'm not sure how well it would work in larger tank. You'd still have to drop the tank to do it right.

New tanks aren't all that expensive compared to etching and re-lining one. Here's one for $228. I'm not recommending that tank nor vendor, just found it with a quick search. You'd still need the connector piece.

If you're close to PA I have a brand new OEM 55L fuel tank, in a box, in my garage, with the connector piece and o-ring...

E30J · « **Reply #3 on:** November 28, 2013, 10:26:14 PM »

Quote from: DesktopDave on November 28, 2013, 09:09:08 PM

I've tried out chelating rust treatments like Evaporust. They work well, but I'd bet twelve gallons or so would get pretty expensive. It also has trouble with fuel varnish.

I've lined motorcycle fuel tanks with Kreem, but that'd be pricey too. POR-15 has a great motorcycle kit, but I'm not sure how well it would work in larger tank. You'd still have to drop the tank to do it right.

New tanks aren't all that expensive compared to etching and re-lining one. Here's one for $228. I'm not recommending that tank nor vendor, just found it with a quick search. You'd still need the connector piece.

If you're close to PA I have a brand new OEM 55L fuel tank, in a box, in my garage, with the connector piece and o-ring...

Hey man.. unfortunately I'm no where close to PA but i appreciate the offer. Also not in America so anything will be pretty expensive

Looks like this is going to be fun.. $:-\$

E30J · « **Reply #4 on:** November 28, 2013, 10:27:57 PM »

Quote from: keflaman on November 28, 2013, 07:56:14 PM

I don't have a lot of personal experience cleaning automobile gas tanks, but if you search the net for something to the effect of "cleaning varnish from gas tanks" you'll get a ton of hits.

A couple of things to consider about the gas tank in our car: The drain plug on the tank isn't very large and there is a crossover tube between the two tank sections. Depending on the amount of debris and rust you have may determine whether or not you have to drop the tank.

Yep i saw both the smaller drain plug and narrow cross over tube thanks. It seems pretty bad in there though when i took the fuel pump out and pulled the filter off it stuck to my hand from the varnish and took a few washes to finally get it off my hands� $:-\$

DesktopDave · « **Reply #5 on:** November 29, 2013, 08:12:00 AM »

Be aware that there are at least three different E30 tanks, if you go the used parts route. Our cars use the smaller 55L tank...I'm pretty sure all the M10, M40 and M42 cars shared this design. IIRC earlier later six-cyl cars used a 63L tank with a connecting pipe...later six-cyl cars also had a 63L but with some type of a siphon off the return fuel line (to pull fuel over the driveshaft hump to the lift pump).

I've pulled tanks out of old BMWs before, it wasn't as bad as I thought it'd be. With the road salt they use for de-icing around here, even small jobs can get pretty challenging. I recall being pretty impressed with the quality of BMW's hardware, as I had very little trouble.

I'm still interested in finding a larger tank to install in my car. Mine is heavily dented, and can barely fit 11 US gallons. AFAIK the only differences between the cars are the wiring for the dual senders, and a different fuel gauge in the cluster to read those senders properly.

deansweet · « **Reply #6 on:** November 29, 2013, 07:28:07 PM »

I don't see how it would be possible to reseal the inside while still in the car.
I replaced my tank with one purchased from Advanceautoparts.com
It was around $150 shipped at the time but I see it is no longer that price. Only issue I had with ours, and it being 360k miles in the salt friendly use Ohio, was the tube that connects the two tubs in the middle. That single part was $50... Consider replacing center support bearing and guibo while you're in there?

E30J · « **Reply #7 on:** November 30, 2013, 05:54:23 PM »

Well.. after taking a look at it i decided to leave it in lol� drained the gas out ran some new gas through the line to flush out any debris and called it a day

Everything is gummy inside but i doubt it will be coming loose any time soon

DesktopDave · « **Reply #8 on:** November 30, 2013, 06:44:38 PM »

The ethanol mixes we have around here will strip varnish out of tanks and send it down the system. I'd definitely change the fuel filter.

I've heard good things about SeaFoam as a varnish cleaner, but I haven't had a lot of luck with it on fuel-injected vehicles. It didn't seem to hurt anything, basically didn't change anything at all. It's good for carb'ed stuff like my bikes though. If you decide to use some SeaFoam, I'd hold off on the new fuel filter until you passed it all through the fuel system.

ryanjv · « **Reply #9 on:** December 03, 2013, 11:16:55 AM »

Quote from: DesktopDave on November 28, 2013, 09:09:08 PM

I've tried out chelating rust treatments like Evaporust. They work well, but I'd bet twelve gallons or so would get pretty expensive. It also has trouble with fuel varnish.

I've lined motorcycle fuel tanks with Kreem, but that'd be pricey too. POR-15 has a great motorcycle kit, but I'm not sure how well it would work in larger tank. You'd still have to drop the tank to do it right.

New tanks aren't all that expensive compared to etching and re-lining one. Here's one for $228. I'm not recommending that tank nor vendor, just found it with a quick search. You'd still need the connector piece.

If you're close to PA I have a brand new OEM 55L fuel tank, in a box, in my garage, with the connector piece and o-ring...

not to thread jack, but i'm also in the same boat where i have to drop the tank for a leak, but was going to clean it as well. If it's patchable, great. If not, I may be interested in that gas tank. My inlaws live in the McCandless/Wexford area, so we frequent there every month

Author Topic: Easiest way to clean a fuel tank..?? (Read 5881 times)

E30J

Easiest way to clean a fuel tank..??

keflaman

Re: Easiest way to clean a fuel tank..??

DesktopDave

Re: Easiest way to clean a fuel tank..??

E30J

Re: Easiest way to clean a fuel tank..??

E30J

Re: Easiest way to clean a fuel tank..??

DesktopDave

Re: Easiest way to clean a fuel tank..??

deansweet

Re: Easiest way to clean a fuel tank..??

E30J

Re: Easiest way to clean a fuel tank..??

DesktopDave

Re: Easiest way to clean a fuel tank..??

ryanjv

Re: Easiest way to clean a fuel tank..??