after a blocked filter or 4 i looked in the tank to find a waxy bone coloured gunk in the bottom and walls and the same gunk but grey on the top of the tank. The tank was spotless 5000 kms ago , got 4000km on one filter then ran into problems. I did have a water problem a month back maybe its related.

1. What is it?
2. how do i get rid of it, would filling tank with methonel or ulp clean it over a couple of weeks driving. ive cleaned the middle third with rags but i cant get passed baffles., maybe I should hire a high pressure blaster with degreaser. Cleaning in situ would be ideal.
3. or if I have to remove the tank should i take this oportunity to replace the steel tank with a plastic tank, current tank standard 80 series L/C.

G'day Tom, if you want trouble free motoring, then it would be best to get rid of your steel tank and replace it with plastic in my opinion. I have a HJ60 cruiser and triton ute, both on WVO and have had heaps of problems with the same gunk as you. I pulled out the cruiser tank, cleaned it out and used a biological agent to stop it. But down here in Tas we have dramatic changes in climate and it seems no matter what I do, except for cutting the tank open and coating it with something, it still develops gunk. My triton is the same but I seem to have it under control with the anti bacterial and keeping the tank full at all times. My start up tanks are plastic and I have a 280 lt tank I stick in the back of the triton and it's had fuel in it through freezing conditions and 35-40 deg temps and doesn't have any problems with it. I stuck it outside in the weather with 60 litres in it for the last 3 weeks to see what will happen, today I drained it and put it back in the shed. We've had sleet, hail, heavy rain and really hot days, but the oil I took out showed no signs of gunk and the tank looks clean. I also have trouble with my steel settling tanks and storing oil in steel drums, they either develop gunk after a few months or the settling tank has scum and thicker oil around its sides. The steel absorbs the heat and cold much easier than plastic, so if you have the chance, change to plastic and save yourself a lot of trouble. I'm chucking out all my steel tanks as soon as I get replacements.

Hi Tom,

I used POR15 to clean out, then coat the inside of my plain steel aux tank on my Landcruiser. I used their same cleaner to clean the inside of the standard tank, but didn't put the sealer inside.

I had cut open the bottom of the aux tank and cleaned out the buildup of fats and brown residue caused by poor filtering in my early days. then I welded the tank up again and used the three stage POR15 process.
POR-15 Shop - Links

Tank cleaner, Surface prep, and then pour in the paint/sealer and turn the tank over and over and over. It seemed to run all over the insides of the tank and has dried really hard and smooth - supposedly not allowing the plain steel of aux fuel tank to act as a catalyst with the oil - which might explain the different reactions happening in plain steel aux tanks, and factory tanks. It cost around $100 from memory and might be a worthwhile step rather than cutting open the tanks. I had something rolling around inside my tank I had to remove and I cut them open before learning of the POR15. They may have an agent down your way, the guy at Malaga Rust repairs was pretty helpful.

I know Brian had a similar problem and coated his tank with a two part epoxy paint after cutting it open, and has had no further problems.

To use POR15 you will need to remove the tank from the vehicle, but you don't have to cut it open.

I found grey gunge once and figured it was algie. A few good does of Algie killer fixed it up, but the grey gunge is really hard to move by simply running BioD for a while.

Hope this helps

Tim

I had this kind of problem when I was hot-filtering the vege.

David, I do dry my oil and it handles the pan test well. But we get days of heavy moisture in the air and it gets very damp, being by the sea we also get moisture laden winds blowing over us. So it's really hard to keep moisture out of the oil and your tanks in the cars or out. The por15 system sounds good and I will look into it, if it works then I reckon it could be better than changing your tanks to plastic. But on the other hand how long does it last and what happens when it gets old and starts to come off, does it main fixed, dissolve or does the tank become clogged. Plus you also have to consider the metal fuel lines and whether they have an effect as they heat up and cool down with temperature changes. I would expect others in places with dramatic and damp weather conditions may have some of the same problems. If I garaged my vehicles, it have a difference, but I don't have a garage and if I did, it would probably be used for something else or be full of junk.

Thanks guys, im going to try and find a plastic fuel tank, Ill clean this one in situ by filling with ulp and driving on the diesel tank for a week, then drain the ulp. Ive tested a small sample and it disolves in ulp.

That's proof it's fat..... I had the same problem as mentioned earlier. It looks waxy or jelly like and is grey to white in colour. Soft to touch, and squashes easily to a paste. And as you said dissolves in ULP.

What happened to me was when I tried hot-filtering the vege, fats go through the filter and end up settling out in the tank and eventually in the onboard filter.

One theory was that if the fuel was run hot enough, the fats would melt and go through. For me it never worked out that way.
Nowadays, I remove all the fat and filter at room temperature.

Please, keep us informed of your findings.

Interesting, as my problems are very much the same. Would it work if you just blended some ULP into your oil for a few tanks fills and open the drain plug each morning after it had settled, The stuff I am using has stopped the red green gunk growing but not the stuff you both describe. My triton has a bit of a starving trouble during the first 30-40 klms, until the recycled oil starts to heat up the tank oil.

Caution: There was talk on the Infopop site re starving the IP.
Longer term exposure was said to cause internal damage.

starving the ip doesnt sound like a good idea so I will try and sort it out.
I cold filter my oil but i used oil from the base of my "5 micron fitered oil "drum. silly me
It had sat in the drum for 4 weeks and water had settled out of it so I got a tank of water/oil. I drained this two days later but it must have left a scum.
So my guess is its water and fat related combination, some fats may have escaped the filter process and settled in the base of the drum with the water. I no longer draw from the base of a drum at any stage of the process.
The scum wasnt a big problem short term ,until I added 10% ulp to the tank. This broke down the scum to a slurry which sucked up and blocked my filters.
Its important to note that with the 80 series tank the pickup draws from a compartment inside the tank. The only access for fuel from the tank into this compartment is through a 10mm hole roughly 10mm up from the base of the compartment. I mention this as when the main tank is drained there is still 10mm of fuel in this compartment. To clean this compartment there is an inspection hatch between the back seats, this hatch removes the contents float gauge and pickup tube.
Im still letting the ulp do its job so I cant report on progress yet.