Bad fuel or not?

G`day Odog,
It could be either. Given enough time & conditons algae will grow. Moreso if you`ve left your vehicle standing with a not full tank for any length of time. Same goes for the service station, that`s one reason why it`s recommended to only fill up at garages with a big turnover. As with rust it`s the oxygen molecules that does it. Obviously you can`t keep a full tank all of the time but if one could minimise the oxy contamination, we`d all be better off. That`s a very simple response but you can google algae & diesel to find a better explanation.

Cheers Rog

G'day Odog
Algea can grow anywhere the conditions are favourable for it. The algae may have been pumped into the tank and has also prospered there.
If there is a lot in the tank/s it would require cleaning out.
It's a good idea to periodically add some bug killer to the fuel so it deals with it or eliminates/inhibits it's growth.

If the situation is up in the warmer, more humid climates like QLD or NT then it is common.

Algae grows at the fuel/air surface.

Water Watch is a good device for warning of water and also pics up the algae too but water dissolved in the fuel isn't prevented from going to the injection system, only detected.

The vehicle fuel filters will also be contaminated and will have to be changed when/if cleaning is done otherwise the circulation distribution of the system will keep recycling the bugs in it.
You/he will still have to treat it with bug killer though.

Hi, I am a retired aviation fuels inspector and both Jet fuel and diesel are prone to an algae called cladisporum which grows on the interface of the fuel and water. It can only survive while there is water/moisture present and while a crook batch of fuel could be the contaminant it is evident that you have water in the tank and it really doesn't matter how you got it you must get rid of it. As water sits below fuel you might be able to drain the water out if you have a drain valve or plug in the LOWEST part of the tank. Some people put a cup of metho in the tank but I am not real confident of the results. The fact that your mate has the algae up to the water dump means that the entire fuel system must be flushed with clean diesel, and any filters that are made of water absorbent elements need to be tossed out in the process.
I have a Nissan Patrol which has an inline filter at the entrance to the fuel pump and it stopped me in the NT a few years ago until I found out about this filter from a Nissan mate, I got it out and it was clogged solid with this algae, but I don,t know if the Prado has the same filter.
Cheers, BillM

Odog - The bugs are cutely called Hydrocarbon Utilizing Micro-organisms (HUM-bugs!).

These bacteria are ever-present and they feed on the interface between the diesel fuel and any water present.
They're more common in above-ground fuel storage tanks - but they can appear anywhere under the right breeding conditions.
The right breeding conditions are a supply of diesel, a supply of water, the right temperature, and generally, stillness of the fuel.

Using a bleach solution in the tank, and/or steam-cleaning the tank, followed by a biocide, is the only solution - as the algae is a prolific multiplier and can produce recurring mats or strands of algal gooey-ness that keeps blocking tanks, lines and filters.

http://www.racq.com.au/motoring/cars/car_advice/car_fact_sheets/diesel_fuel_sludging

This following mob (link below) flog a bug filter, and they have an extensive write-up on the bugs (see "diesel bugs" in the LH menu).
I cannot vouch for their filter, I've never used it - but they have testimonials from the oil companies that say the oil companies noticed a reduction in algae when they tried their filter.

http://www.morison.com.au/De-Bug.htm

Cheers - Ron.

Thank you all, some great info in all the replies. I will get some anti bug stuff to add to my tank, my prado is all good, (touch wood). But if I can prevent or slow down any nasties, it will be worth it. Fella with the cruiser has been filling up at a servo where i know others have had dramas. I think he would have got a dose of it there, and has bred up I guess. Thanks again lads. Happy travels. Cheers Odog

Odog

Toyota have a injector cleaner/fuel treatment. May be best to stick with there products if your still under warranty??

Cole