Gas Tank Flush - best method

[bgray]

Hey All,

I need to flush the gas out of my Fj40. Tank is a third to half full (5-10 gallons), but fuel is about 20 years old. Do you think it is sufficient to shake the cruiser then drain the tank, refill with a gallon of fresh gas and repeat a few times; or do you think I need to pull it entirely and flush? Since there was a good deal of gas in the tank, I was thinking that maybe it didn't settle out too much, as would have been the case if it evaporated dry -- similar to what my carb looked like (varathane muck). Note that I do plan to replace all fuel lines, filter and the fuel pump.

If I do need to pull and flush it, what is the best method. The cruiser has very little rust so I doubt there is rust in the tank.

Thanks.
Brian

 

[joeyg1973]

Hey All,

I need to flush the gas out of my Fj40. Tank is a third to half full (5-10 gallons), but fuel is about 20 years old. Do you think it is sufficient to shake the cruiser then drain the tank, refill with a gallon of fresh gas and repeat a few times; or do you think I need to pull it entirely and flush? Since there was a good deal of gas in the tank, I was thinking that maybe it didn't settle out too much, as would have been the case if it evaporated dry -- similar to what my carb looked like (varathane muck). Note that I do plan to replace all fuel lines, filter and the fuel pump.

If I do need to pull and flush it, what is the best method. The cruiser has very little rust so I doubt there is rust in the tank.

Thanks.
Brian

If you have to flush it go to a pet store and get a bag of the sharp gravel that is put on the bottom of a fish tank. Use that along with whatever chemical you use to shake around in the tank.

 

[71cruiser71]

do you have the OEM tank? if so there should be a bolt on the bottom of the tank. hard lines should be fine, replace rubber hoses and fuel filter.

 

[craptabulous]

if you pull it get it dipped in a kreasote tank at a radiator shop .

 

[destin]

Should be a plug on the bottom of the tank to drain it.
Make suer you drain it in a large enough container.
Half of an 18 gallon tank is a lot

Then you can have it cleaned and resealed at a radiator shop

 

[BJEC69]

I just went through this process. Drain the tank into a suitable size container as mentioned. I could not find a local radiator shop to clean it, so I powerwashed the tank through both the snorkel and the fuel sending unit hole in the tank. Leaving it wet, I added some HVAC system cleaning acid to remove the rust. I powerwashed again a few times. I used the shop vac blower option to completly dry the tank, sprayed some WD40 inside to prevent any flash rust, and reinstalled drain plug with new gasket, installed the tank and refilled. So far so good. If the tank is real bad, new OEM tanks are still easily sourced for a reasonable cost. You always have to figure in the time factor vs money. Hope this gives you another option. Brendon

 

[bgray]

Thanks for the responses. I'll call a few radiator shops to get a quote on flushing & resealing.

I recognize that doing a full flush & reseal is the best solution, but if in inspecting the tank I don't see any signs of rust or leaks, it is necessary verses flushing on my own (e.g. add a gallon of new gas, shake like crazy, drain, repeat)? Since the tank is 40 years old, I suspect the answer will be to have it correctly serviced.

thanks,
Brian