I know our cars are getting on in age and thought it might be a good idea that the almost 30 years of accumulation of varnish, dirt and other sludge inside the petrol tank be boiled out in order to not get caught up in the CIS system and cause phantom problems. This involves removing the petrol tanks and I was hoping somebody in here has done it so they can tell me how its done.

I removed my 83 iS tanks ...a split tank set-up. Not sure if it's same on 323's. This is a dirty job at best. Steam clean/pressure wash underneath if you can. You will need eye protection and face mask! Best to do this on a lift..if not make damn sure your jackstands are set solid. YOU will be under the car!
Drain the tanks as much as possible. Remove rear seat to get access to fuel pump housing. Disconnect wiring. Your choice to take out fuel sender/pump. disconnect hoses at that section. Remove the filler hose. access from under right rear fender.
Remove the tank crossover protector cover. Loosen the tank front retaining bolts(13mm ?) do not remove! This should give you enough slack to remove the crossover hose. Gas will gush out so don't be under it when you take it off. If you are going to replace it just puncture the hose and let the gas drain out. Take proper precautions!!!!
Loosen the rear tank retaining bolts. Remove the front bolts, to let the tank hang down a little. Then remove the rear bolts. The tanks are heavy so dont be under them when they drop. I used a cardboard box to cushion the fall. You might have to wiggle it a little because of caked dirt and stuff.
Once down you can remove any incidentals that might be still attached.
I took mine to a radiator shop to have them cleaned and recoated. Cost me $150.
Take this time to inspect your fuel and brake lines for rust. You might have to replace them as well and better to do it when there is room to work with. There is an ETK access at the old E-21 forum. Get a parts diagram of the fuel tank for reference. It'll help. Don't know if this will be of any help to you. If I left anything out jump in my S--- forum members.
Good luck in doing this. Take your time and be sure to take every safety precaution!!!!!

I know this may sound a little hokie, but here is what I do. Once the tank is out, and rinsed out, pour in a bunch of salt, ice cubes, and toilet bowl cleaner or coffee pot cleaner. Shake it around. The salt and ice will scour away any scum or rust. The cleaner will help to chemically remove any scum. Once your arms get tired or the ice melts, rinse it very well with clean water. Allow to dry and add a can or POR15 gas tank sealer or similar. allow that to dry and your free to reinstall. Hair dryers help dry the rinse water faster to prevent any surface rust forming on the freshly prepped tank. Works fantastic, it's quick, doesn't cost $150 bucks, and you don't need to make two trips to the radiator shop. Me and my friends have done this on at least 20 tanks over the past 15 years. Like I said, it works great.

There are some gas tank cleaning ideas and useful links here:
http://forums.bimmerforums.com/forum/showthread.php?t=868941&highlight=Gas+tank

I removed both of the 323i tanks and drained all the varnish that was in there.

It was Nasty.

Anyone got their car up and able to measure how high you car needs to be to get the tanks out? I'm probably going to do this real quick. I need to redo the fuel lines under the back seat anyway.

I removed mine on regular jack stands set at the max level of a standard jack (18"?). Not very high.

$150 for a tank cleaning? Thats a rip off. I paid $50 for both of mine to be done.

$150 for a tank cleaning? Thats a rip off. I paid $50 for both of mine to be done.

I went to 8 different places b4 finding one that would do it for under $100/tank. Paid a premium price I know but it needed to be done and I didn't want to deal with the mess/toxic chems in a DIY job. I know of no other E-21 drivers in this area so have to forge my own way...and at times it is expensive!!
Doing my part to keep the economy thriving!

I checked my receipt and it was $50 a tank so $100 for the cleaning. I sit corrected.

Wouldn't it be simipler to just buy new ones? I'm mean that old, rusty, and work. I'd just buy new ones. I know, that's just what "I" would do.

Wouldn't it be simipler to just buy new ones? I'm mean that old, rusty, and work. I'd just buy new ones. I know, that's just what "I" would do.
sure its easier, but they'd cost you about $660 shipped. As you said in another post, I'd find better things to spend my money on.

Yes I did say this, but it's what your spending money on that counts. If your intention is to keep the car till who knows when than it's worth it and a waste of time cleaning an such. If you know you won't keep the car for long, then yes cleaning is the way to go.

PS: I just responded to that other one comment, and I explain the difference.

Thank all of you for your input! I want to get the fuel system as clean as possible before I start putting in the Motronic system so nothing old gets dislodged and causes problems. How much varnish is expected to be at the bottom of the tanks, is there enough to smear all over my asshole neighbor's weenie prius and make his car an environmental nightmare?:redspot

Thank all of you for your input! I want to get the fuel system as clean as possible before I start putting in the Motronic system so nothing old gets dislodged and causes problems. How much varnish is expected to be at the bottom of the tanks, is there enough to smear all over my asshole neighbor's weenie prius and make his car an environmental nightmare?:redspot

It depends on how much gas was in it when it was parked and how long it sat. I put new tanks on mine from the BMW stealer and they were around 460.00. These cars do not like dirty fuel. Clean everything.

$460.00 each? Expensive but worth it, I plan on keeping mine!

I understand what you're saying about buying new to avoid future problems, but a good set of used tanks is hardly going to leave you stranded on teh side of the road someday.

I plan on keeping mine too and $460 is hardly worth paying for ANYTHING that is readily available used, in perfect condition, for pennies on the dollar from forum members or bmw scrap yards. When prices are that high for something so retarded I consider it NLA.

Call 2002ad.com and see how much they want for a set.

Except for wear items, most of the parts on my car were purchased used on ebay or from a junk yard. Bumpers, fenders, hood, entire interior, dash, carpet, seats, center console, wheels, strut tower brace, sway bars, 323i trailing arms, turbo, manifold, volvo fuel distributor, throttle body and so much more I can't even list it all. Just about everything can be restored to like new or better condition with some elbow grease and time.

I've never bought anything from a dealer, and the only stuff I buy new is wear items. It's your money, you can waste $880 on new fuel tanks, guys like me would spend it on coil overs, camber plates, and a new set of tires since I go through them every 2 weeks. Or I'd spend it on megasquirt or a used SDS system and crank things up to 300 hp. Or maybe a big brake kit from Massive Lee and some nice used wilwood calipers... ooo the possibilities are endless.

Well I like new with old not old with old.