Fuel type tank compatability...

[GreggK]

Hello all,
I recently bought a new fuel tank for my '86 2wd. The tank is going to be supplying a diesel engine. This is actually the second tank I bought for this van but that's another story. Before I purchased the first tank I asked the vendor if the tank was compatible with diesel fuel and the answer was yes. So just last week I went and picked up another tank from the same vendor since the last tank I got from them would work with the diesel fuel. I finally got around to opening the tank today and it looks very different from the first tank. The differences are that the first tank had plugs in all the openings and caps on all the hose lines. It was also a dull silver color and you could see the outside was painted with the caps and plugs in place.

The tank I just opened today has no plugs or caps and it is a shiny silver color. My concern is this. If you shop for 2wd tanks on Van Café you will see a note at the bottom of the page stating the tank is not suitable for diesel fuel due to a coating on the inside of the tank which may dissolve if in contact with diesel fuel.

I called the vendor I purchased the tank from and explained my concern and asked for any info that I could do my own research with. After a brief hold the vendor returned with the answer that "it should be ok".

Can anyone give any input on this topic. I'd hate to contaminate or do any damage to my new engine.
Thanks GreggK

[Zeitgeist 13]

I know nothing about the internal coatings of tanks, but my experience with a silver late model tank from CIP1 (going into an early model van) is that the curvature of the bottom did not conform easily to the shape of the harness brackets. I had to fuss and muss with them endlessly.

On my personal van, I just flushed the stock WBX tank, and then ran two tank vent hoses with an atmospheric filter up each rear pillar. No problems so far.
_________________
Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[Dampcamper]

If the tank has zinc coating (as in a traditional galvanized coating) the sulfuric acid in the diesel will dissolve the zinc and this will gum up your injectors and pump. ("Gum up" is too light a term here. It will ruin them.) Even todays "Ultra-low sulfur diesel" fuels will do this, maybe just a little longer before you have to replace your injectors and pump.
"Terne metal" (steel coated with what is basically a high-lead content solder) is one possibility for diesel tanks. Probably some phosphatized tanks out there too.
You'll have to inquire what the anti-corrosion coating is.
(Going back to maritime roots, lots of vessels were built with uncoated "black iron" diesel tanks, the exterior being painted for corrosion control. They lasted pretty well if the steel was thick enough to begin with, but did better if removed, cleaned and recoated every decade or so. This routine is not listed in your Vanagon maintenance schedule.)

[CdnVWJunkie]

[Gizmoman]

Now you've got me worried. I replaced my tank quite a while ago and have been having a stumble when I floor it - never related it to the tank. I wonder if it's zinc? Mine was coated with silver and I believe it was on the inside as well.

Other than the stumble at WOT (and holding it there for a bit) it runs great.
_________________
82 Vanagon Westy - AAZ 1.9 TD, HE200 Holset, WAIC, 27.75 dia tires, Electric power steering, 5-speed AAP w/.078 5th
Oversize spare carrier - stock location (no longer for sale).

[calo1956]

I did get a new tank and it had plugs and all were painted the silver color you described. It is for a gas bus though. It has been 2 years since i installed it, but to the best of my recollection the inside was not painted.

[GreggK]

So it was eating at me all day and I just couldn't stomach the "it should be ok" answer I was given so I called back the vendor. Eventually I got to talk to someone who seemed to have more power than the original employee I was speaking to. Unfortunately their solution doesn't seem too promising so far and it sounds like they don't have the resources to pin point who the supplier is that they got the tank from so they can contact them and ask if the tank is suitable for a diesel application.
So the ball being in my court I need to go a plan "B" and figure out a solution to get what I need.

[GreggK]

I thought to try a few diesel flushes to dissolve any interior coatings if preset but I don't know if that would be thorough enough to feel comfortable with. When I originally started this conversion I planned to replace everything fuel delivery related with "new" so I've since recycled the original tank. It might just come down to finding a vendor who can give a definite answer if the tanks they carry are suitable for diesel application or if they can call their supplier and ask them. I WILL find out a solution to this and follow up to help out anyone else doing a diesel conversion but right now it sounds like the best thing to do is wash out and reuse the original tank just like they suggest in the FAS install manual and like Casey did.

[GreggK]

Sorry to start a thread to get you worried Gizmoman.

[djkeev]

An Absolutely fascinating topic!

Who woulda thunk?

I stumbled across a US Navy paper on this topic.
Also all sorts of links to information documenting sludge build uo and injector failure.

Dave
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http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

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http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[Gizmoman]

[djkeev]

Methods to test for a zinc coating include licking it..... seriously!

Step 1
Prepare a solution of three parts salt to one part water that will be used to test the steel sample. Exposing the steel sample to the salt and water solution is the quickest and easiest way to determine whether or not your sample has undergone the galvanization process.

Step 2
Dip an old cloth into the salt and water (saline) solution and wipe it on the sample of steel. Set the sample aside for 24 hours to allow the it to develop rust. Heavily saturate the sample in order to allow the saline solution to permeate the steel.

Step 3
Examine the sample for the presence of rust after it has rested for 24 hours. Untreated steel will show the presence of rust within a day's time, while galvanized steel will not allow rust to form. The zinc coating becomes a part of the structure of the steel during galvanization and prevents corrosion.

Step 4
Lick the sample of steel if you are still unsure whether or not your sample has undergone the galvanization process. Galvanized steel tastes chalky and the taste is distinct and very noticeable.

Step 5
Assess the results of your tests and look closely at the color of your samples. If your steel sample shows variations in color and pattern and lacks the presence of rust, it is probable that the sample has been galvanized. If the sample is uniform in color and it rusts, it is safe to assume that it is untreated steel.
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http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

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http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[GreggK]

That's good to hear Gizmoman. From the research I've done so far I think your right that you would have far more problems than just a stumble.

Dave,
WOW you really looked into this. I'll have to re-read the testing procedure a few times and possibly follow that route. I don't think I'll be able to reach the inside of the tank with my tounge which is a bummer since it sounds like the easiest and more undetected test. Only apprehension is that once I start testing, either positive or negative, the tank is mine. As it stands I can still return the tank. I did use an inspection mirror and light to look around in there but its too hard to tell if there is any coating or just an over spray through the filler hole and the sender hole. They are the only locations I can inspect through.

I really want to get this figured out for sure. I do all projects meticulously and seriously, be it for work and more so my personal projects. I've spent many patient hours working on my van and it would be very upsetting to have to go back to the drawing board over a potential problem I can avoid now. Thanks again to everyone for getting this thread rolling. Dave, can you provide info where I can look up that info you had found. It is also interesting to me as well. Thanks GreggK

[Gizmoman]

You may find this article interesting.
https://www.bp.com/content/dam/bp-country/en_au/media/fuel-news/long-term-storage-diesel.pdf
It also mentions that brass is another metal that doesn't get along with diesel.

I'll bet there's a lab somewhere that could tell if there was zinc in my fuel (from the tank). Probably cost more than a new tank though.
_________________
82 Vanagon Westy - AAZ 1.9 TD, HE200 Holset, WAIC, 27.75 dia tires, Electric power steering, 5-speed AAP w/.078 5th
Oversize spare carrier - stock location (no longer for sale).

[GreggK]

That was another thought I had too. Pour some diesel in the tank, slosh it around and let it sit awhile so if it was going to dissolve anything it would and then find that lab and get it tested.
This is such a bummer that instead of putting up my new tank this weekend and being that much closer to start up, I'm playing out these scenarios in my head. Its better safe than sorry thou. I think I'll call Van café/RMW this week and try to get to the bottom of where they came to the conclusion about their tanks not jiving with diesel.

[Gizmoman]

I agree, you should be able to get a definitive answer. The tank I had in my van when I bought it (used but stock diesel). the tank had some sort of stuff that looked like an epoxy coating on the inside.. I ended up installing a new one for other reasons.
_________________
82 Vanagon Westy - AAZ 1.9 TD, HE200 Holset, WAIC, 27.75 dia tires, Electric power steering, 5-speed AAP w/.078 5th
Oversize spare carrier - stock location (no longer for sale).

[IdahoDoug]

What about calling around to see if there is a service in your area to save antique fuel tanks by coating the interior and asking them if they have a diesel safe coating for your new tank? It's a common service in classic and antique automobile restoration.
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[?Waldo?]

Interesting. That's the first I've heard of any of the tanks being incompatible with diesel.

[CdnVWJunkie]

[djkeev]

Also, the stock VW tanks have very fine screens inside them. These would be sealed shut with any treatment.

Do the replacement tanks have similar screens? ..... I suspect not.

Dave
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Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

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http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert