On-car Fuel Tank Cleaning?

Krzysztof

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Hi,

Is there any way to clean the tank without pulling it out from the car.
I'm telling about situation where there is not a rust in but a lot of debris.

How to remove them?
I was thnking about the Venturi effect-based tool (e.g. brake bleeder) which is creating a vaccum being supplier from compressor with a containter for dirty fluid.

Maybe dirt can be dissolved somehow and washer with the tan still on the car?

Do you have any experience?
 

Paul Wegweiser

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Removing the tank should not be very difficult. (5-6 bolts?) A quick Google of "fuel tank cleaning techniques" will offer up some options. Instead of shaking a chain around mine, I emptied my 5lb penny jar into my tank and sloshed all the coins around inside it (with lacquer thinner) for about an hour. My shoulders hurt, but it did a great job of removing varnish and loose stuff.
 

Krzysztof

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Removing the tank should not be very difficult. (5-6 bolts?) A quick Google of "fuel tank cleaning techniques" will offer up some options. Instead of shaking a chain around mine, I emptied my 5lb penny jar into my tank and sloshed all the coins around inside it (with lacquer thinner) for about an hour. My shoulders hurt, but it did a great job of removing varnish and loose stuff.

It is true for E3/E9 ... My bad I'm asking about other BMW where it require removal of the complete exhaust, driveshaft and thermal protectors. I do not have an access to lift or garage to play to long. I'm in a little hurry.

There is a half-jar inside the tank and most of debris (some were there from zinc peeling of from metal the pump frame/bracket).
Of course there is a sand-like mud in some quantity.

The best would be to clean it with an agent which is not explosive using a pressure washer but no idea how to...

Wondering if light kerosene could be used as it can be left in some portion and it is not explosive as a gas is.

o_O
 

Cornishman

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Diesel has good cleaning properties, I think this is due to the detergents, also it is not flammable. But it won’t address the sand like pieces.
Could you rig up a suction pump, filter to remove the debris and then return it back into the tank, keep this going for some time? But, non explosive fluid is required.
 

Krzysztof

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Interesting to consider to use few liters of a diesel.

Some diesel which would left in the end should not make any problems mixed with a gasoline later.

Run the pump with a filter and let it circulate for some time could be a plan.

I removed the fuel with the outside pump. It survived but in the past I killed three internal pumps that is why I'm investigating the way to remove debris.
Rear pain is gas is containing ~20% of ethanol today which is absorbing water.

I heard from the owner of classic car collection he's keeping 1-3 liters inside tank as modern gasoline is clogging the carburetors quite fast once they are standing not used for a while.

Would make sense to use the pump where the fuel is not coming through it (non-standard fuel pump)? Which type to use?
 

Cornishman

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What type of pump? As no real pressure is needed, I expect a small centrifugal. But I would search for one that agricultural dealers use to empty fuel tanks of tractors, to pump into containers used hydraulic oil etc. They typically run off a 12 v battery and have a pipe with about 20mm ID.
Some have built in filters for when they are used to return diesel afterwards, ie give it a clean on the way back in.
I would go in the top where the fuel level indicator goes, then use it like a swimming pool cleaner.
However, might be worth coating the inside with POR tank lining stuff, for that I think you need to remove it.
Good luck and send us photos.
Regards
 

Krzysztof

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Thanks for good hint.

I will check for agricultural-like pump availability. I have one with standard garden hose in- & outlet, driven by the drill. Maybe I will try to use that one.

20mm dia. makes sense due to size of debris. The biggest amount of debris is in the half-jar where the pump is located with the level sender.

Hope I will be able to make first try during the weekend (day is short, car outside and snow is falling)

I will make pictures to show the inside. I was about to make some last weekend but got too focused on pumping out the fuel (being covered with fuel vapors).

I do agree the best would be to remove the tank and clean it under pressure and paint with some 2K paint. I have even spare, used one (for verification) but short term not really able to exchange them outside.

Good in a bad, inside is relatively without any significant rust but rather mud or other debris probably coming from the "mud-like" layer covering the walls of a tank.

Will be back with some pictures
 

tferrer

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I'm in the middle of this operation now. I may end up just removing the tank depending on the amount of debris/rust scale left in the tank but I've already removed 80% if it using this method. Purchase a 12v fuel transfer pump (gravity siphon wasn't strong enough to pick up larger pieces) and get a couple inline wix fuel filters on the intake side. Vacumn up your mess (may take a couple cycles) and then use a fresh fuel filter-or 2 in-line, to transfer from your fuel cans back to the car.

This is the pump I purchased
Orion Motor Tech Diesel Transfer... https://www.amazon.com/dp/B019ZD3R52?ref=ppx_pop_mob_ap_share

Note: I used an adapter to reduce the intake hose size to 3/8 (I think) as the included 1" hose intake on that pump would empty the tank in a couple mins at most and you'll need the additional time to move the pickup hose around your tank.
 

Krzysztof

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Thanks for your update.

Sorry for late feedback - no time earlier.

I have purchased a pump like below, 5liters of kerosene and plan to but another 5 liters of diesel (not done yet),
1638995984039.png


It is told to be 24V/12V compatible. In the comments section in the shop someone wrote it was to weak at 12V.

In the user manual I have read it is only for light oil and diesel fuel. It is forbidden to pump water and vaporous fuels (including gasoline/petrol).
the diameter is relatively big.

There is a filter but it is poor quality and not dense enough.

We have snow here and - from other reason - I'm not able to make it this week so I'm considering to give it back and look for better quality part.

All the pumps I have seen have operation time limit: 30 minutes max.

I'm still quite confident I can clean it up.
For sure in-line fuel filter has to be change too after clean-up.
Expecting kerosene & diesel mixture could help to remove the "dust" and debris.
It is still a risk of other dirt hanging over which I will not be able to remove.
 

tferrer

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It works fine but you can't use the the existing hose barb with the kit. It's for a 1 inch hose which is way to big. Get an adapter at the hardware store to bring it down to 3/8 diameter. 12v is plenty strong. The filters you want to use will be a Wix inline filter that you can see through. You'll see what is coming out of the tank. Here are the ones I'm using..

Wix 33003 (3/8") In-line Fuel Filter, Pack of 4 https://www.amazon.com/dp/B016OVZ2H...abc_14T5THF3KAZ0F0Q38T97?_encoding=UTF8&psc=1
 

Krzysztof

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Thank you for the hint. I need to buy a bunch of filters.

This pump is capable to go with water and gas:
1639001465841.png


Maybe because it has plastic impeller, not a metal, like the pump I bought.

Still wondering if not to return the pump as I had no time to use it so far. The one above looks to be more universal for the future.
 

Krzysztof

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It works fine but you can't use the the existing hose barb with the kit. It's for a 1 inch hose which is way to big. Get an adapter at the hardware store to bring it down to 3/8 diameter. 12v is plenty strong. The filters you want to use will be a Wix inline filter that you can see through. You'll see what is coming out of the tank. Here are the ones I'm using..

Wix 33003 (3/8") In-line Fuel Filter, Pack of 4 https://www.amazon.com/dp/B016OVZ2H...abc_14T5THF3KAZ0F0Q38T97?_encoding=UTF8&psc=1

May I ask how's you experiment is moving?

Is the pump able to suck the diesel/kerosene by itself or it has to be filled earlier before pumping?

What was the length of the pipes you've been using?
 

Krzysztof

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My congrats. I need to wait but hope it should also work for me.

In the meantime I have disassembled the fuel pump which's stopped after a year in the tank. Will make pictures tomorrow.
 

Krzysztof

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Today was the day as temperatures were line in the early spring (>10degC).

Here's the setup:
setup.jpg

I'm very satisfied with the pump. It has plastic parts inside. The first I bought has metal internal parts which are prone to corrosion and sparkling (worst case but I prefer to avoid any possible risk).

I used diesel mixed with kerosene. There was also some gas residue in the tank.

First run - mostly big particles:
filter0.jpg

Some runs after (new filter) - medium mud:
filter1.jpg

After few runs - dense mud barely visible but clogging the filter (visible deformation cause by presssure applied on the filter blocked by mud):
filter2.jpg

In the end filter was not blocking the flow.

All the activity repeated for two parts of the tank (E30 - 65liters).

Next steps:
- replace the main fuel filter
- change the pump to brand new
- fill the tank with fresh gas fully to protect against further surface rust

It would be good to be able to turn on/off the pump locally (not by disconnecting the clamps on the battery).
Pump Speed/suction adjustment might be helpful in some cases.
LiON battery pack or motorcycle battery would make the setup more versatile. I used car's battery.

Pump is really fast. over 10 liters are pumped below 1 minute, so can be use to fill the tank from the container.
 

Cornishman

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Krzystozf
Did you just run it in a loop straight back into the tank, or into cans and then pour these back now and again?
Will you leave one filter in the system which is visible to help you to see if there is more debris being pulled through?
 

Krzysztof

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I was pumping it into the canister and than back into the tank for each half of the tank several times changing filter once it was blocking the flow of the fuel.

I have also changed the main fuel filter and cut it to check how dirty it was but it has no big debris - only the thinnest parts.

The plan is to mount new filter after few months of usage.

Of course I'm expecting there will be some more debris appearing. I hope I will be able to change/renew the tank still this year
 
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