How/should I remove old gas?

Status
Not open for further replies.
K

kpatter

Joined
Aug 26, 2011
Messages
91
Location
texas
I have recently purchased 1990 BMW 535i at an Auction. This was a drug seized car. The auctioneers gave me all paperwork to get title etc..

The car has sat idle for who knows how long and there is still gas in the tank. I have seen plenty of you tube ads about removing the fuel tank and even been told I can have the tank "boiled" to remove all rust etc..
I really don't have a place to remove the fuel tank as I live in the city. Is this really necessary?

Can I siphon and fill with hi octane gas? Berrymans? Any other ideas?

Any input really appreciated.
 
Fill it with high octane, a good-quality PEA-based cleaner (Gumout) and run the gas out of it with a long drive.
 
Berryman's B12 is just lacquer thinner and acetone.... Nothing more. You can mix your own a LOT cheaper.

I once bought an EFI Mustang from a dude that was in prison for 10 years (his family kept it for him all that time).

It was half full of old gas - - I dumped in another 5 gallons of fresh gas and drove it home.

Modern EFI engines are very, very, very, very, very forgiving of "old gas".
 
Gas tank on the E 28s had a plug. Dunno about the E34.. I would siphon as much as you possibly could. Raising the back of the car would help. That is about the last decent BMW
 
perhaps this?

$6.95 harbor freight. Get as much of the old out as you can.

[Linked Image]
 
Most newer vehicles have a blocking device down in the filler neck that prevents a siphon hose from being inserted down into the gas tank. I can't speak to weather or not the 1990 BMW 535i has this.
Modern EFI engines may be very, very, very, very, very forgiving of "old gas", but the fuel systems (especially the injectors) are VERY UNFORGIVING of the varnish that eventually forms in old gas.
 
I would definitely just put fresh gas in and drive it. Draining the tank seems like to much work for basically no reward
 
Last edited:
Originally Posted by addyguy
Fill it with high octane, a good-quality PEA-based cleaner (Gumout) and run the gas out of it with a long drive.


THIS!
 
The OP didn't tell us how long the car sat unused. 1 year? 5 years? If much over 1 year, I would siphon the old gas out and install new gas with a good cleaner like Techron or GumOut. Keep an eye on the fuel filter, if applicable.

While I don't recommend it to others, I would siphon it out the same way my great grandfather did, LOL.
 
Originally Posted by Linctex
Berryman's B12 is just lacquer thinner and acetone.... Nothing more. You can mix your own a LOT cheaper.

I once bought an EFI Mustang from a dude that was in prison for 10 years (his family kept it for him all that time).

It was half full of old gas - - I dumped in another 5 gallons of fresh gas and drove it home.

Modern EFI engines are very, very, very, very, very forgiving of "old gas".


My mom had a strange little convertible that I can't remember the model for that sat in the garage, buried by junk, for at least five years. All of the fluids looked terrible and the gas tank was half full. I told her I would bring all of my stuff down to visit next time, if she wanted me to change the fluids; either that, or have it towed somewhere to have the fuel tank siphoned and at least the oil changed.

She got a jump and drove it. I have no idea if she filled up with gas before it was on E or if she got any of the fluids changed. She said the car was fine when I asked, though she is likely in the top 1,000 people who would ignore major signs of trouble in a vehicle....The car was gone soon after. I never asked if it was junked, stolen or sold...
 
If the car has a gas filter remove it and attach a plastic hose to dispense into a container. Turn the key to position 2 and the pump should just pump it out.
 
Old ethanol gas that we have today does not last like gasoline used to. Manufacturers say don't leave it a month. In my personal experience I would not use any old ethanol gas older than a few months unless it had been properly treated with something like STA-BIL In particular, if you are in a humid environment, like near the ocean, ethanol gas gradually absorbs moisture and eventually you get what is called phase separation. If you looked at some in a test tube you would see green gunk on the bottom with good gas floating on the top. Unfortunately, the car sips the fluid on the bottom first and gets the gunk. Ask around any marina or boat engine shop about this problem and you will hear lots of horror stories, and many motorcycles suffer from this too after being parked for a winter.
 
Originally Posted by LazyDog
If the car has a gas filter remove it and attach a plastic hose to dispense into a container. Turn the key to position 2 and the pump should just pump it out.

Fuel pumps won't run without oil pressure or a computer signal.
 
Originally Posted by addyguy
Fill it with high octane, a good-quality PEA-based cleaner (Gumout) and run the gas out of it with a long drive.


This. I'm partial to a cleaner that also removes moisture, since it's been sitting awhile condensation may have gotten in the fuel.
 
The aforementioned phase changed gas can be rehomogenized. Add 4 oz of Stabil and a couple gallons 93 octane gas and run it. Personally I wouldn`t drive it very far at first. Gas in a modern vehicle is not freely exposed to air so lasts longer than gas exposed to air.
 
I'd try the siphon down the gas fill. It might be old enough to not have an anti-siphon screen in there.

Or look at the fill hose, how it connects to the gas tank. Maybe you can easily disconnect the fill hose right at the gas tank and then siphon at the gas tank.

Having said that, I recently started a car that sat for 3+ years. It should have had 10% ethanol 87 octane in it. Opened the gas tank cap, the gas still smelled like gas. Some people say the gas will smell weird if it's turned to varnish. It started right up. I then babied it until putting some miles on it with 91-93 octane.

Either way, after starting it, I'd change the fuel filter sooner rather than later.

edit: I did remove the spark plugs and put a little oil in each cylinder, and turned the engine over a few times by hand to make sure it wasn't seized. It wouldn't hurt to do that on the BMW, but probably unnecessary unless it's sat for a very long time.
 
I just pull off the fuel filter put a hose on the line down to a gas can and jump the fuel pump relay and pump all the gas out and use it for starting bonfires etc.



Ive also done this in preparation of changing a gas tank or sending unit
 
There was a story on the news a few years ago about a guy that tried using a shop vac. The flames shot 20' into the air!
 
Status
Not open for further replies.

Similar threads

C
Best carbon remover gas additive
2
Replies
21
Views
1K
Lubener
J
how to lower hydrocarbons for emissions test ?
3 4 5
Replies
87
Views
4K
johnmyster
J
Water In Fuel Filter - Sensor Issue?
Replies
9
Views
769
jtay2024
Warstud
Do I Need High Octane Gas?
2
Replies
31
Views
1K
Zee09
SupremePossum
How often to change oil in unused portable generator?
2 3
Replies
43
Views
6K
MSCH
Back
Top