I’m in the process of E-Rod swapping my 240SX. And I figured this might be a good time to pull the gas tank and clean it. The car has been sitting for around for about 14 years, and I figured the tank must be pretty nasty. It certainly didn’t look too nice, although it looks better than I thought it would.



After some cleaning, it is looking better, but still not very nice. Of particular concern is that white crusty stuff. It comes off with Chemtool if you scrub. But it is going to be difficult to impossible to do much cleaning further in the tank, especially since there is a baffle that completely blocks access to about a third of the tank.



I heard about using a chain to clean the tank. And this seems to help quite a bit. But admittedly, it’s not actually looking very spotless, as there are still some white deposits.



At the end of the day, it doesn’t look like I am going to get the tank spotless. And when I have asked around about professional gas tank cleaning, people react as if I have brought up the dumbest thing in the world. In other words, it looks like I am on my own. Honestly, I am not so sure I can get the tank much cleaner than this. This begs the question: How clean does a gas tank REALLY need to be? Is this something that will just clean up with time as the tank is filled with fresh gas? And might the deposits simply get trapped by the filter over time? Or is this something that I really need to be concerned with?

 

That white powder is usually from water contamination in ethanol fuels. It’s nearly impossible to get it all out and it will scale off of the tank over time as gas and the ethanol in modern gas wash the walls of the tank. All those particles are notorious for clogging up filters in the fuel system. I hate to say it but I would just replace the tank

 

Not really an option for a 240SX. At least not at any kind of reasonable cost. The only new gas tanks I have found go for north of $1000. That’s ALOT of C5 fuel filters right there! In any case, I have probably removed at least 75-80% of the stuff. So hopefully, it isn’t TOO much of a problem.

 

I actually found out what those white deposits are. For the heck of it, I tried burning a piece of paper towel after wiping down those deposits. The deposits on the paper towels turned from whitish-gray to yellow when the paper towel was burned. One notable compound that does this is zinc oxide. This makes sense, as sheet metal parts (such as gas tanks) are often made from galvanized steel. Those deposits are zinc oxide due to the corrosion of the galvanizing layer.

 

maybe you can get rid of all zink with acid and then do an epoxi coating.

 

I’ve done it with dirt bike tank once with good results. I think it’ll take a lot to do a car sized tank though.