Gas Tank Cleaning

High MX
Elite Member
Joined: October 9th, 2012, 12:54 pm

July 14th, 2013, 3:11 am #1


I don't have any pictures but the task is straightforward. Hopefully your tank is empty or near that. If it isn't you will need a hand to steady the tank and have some kitty litter standing by in case you spill any gas.

These are the steps I took to clean out my tank so they might not work for you. The important thing to take from this is vinegar works to remove rust and gunk from your tank. I was ready to replace mine and decided, what the heck, I have nothing to lose. I couldn't believe how well the vinegar cleaned the tank.

1. Disconnect the battery.

2. Pull up the rear seat, disconnect the fuel pump and fuel level harness. Push the harness and grommet down through the floor so you can drop the tank.

3. Jack the rear of the car until the rear wheels are about 6" off the ground and support it with jack stands.

4. Support the rear of the car with jack stands. Yes it is worth repeating.

5. Disconnect the fuel, return and vent lines.

6. Disconnect the fuel filler and vent lines.

7. Support the tank with a floor jack.

8. Remove the four 12 or 14 mm bolts and carefully lower the tank.

9. Remove the fuel pump, fuel level sending unit (clean it and verify it works), vent system and associated lines and hoses. Take notes or pictures so you can put everything back together. Replace any dry rotted gaskets.

10. Drain and properly dispose of any residual gas.

11. Grab at 2 to 3 gallons of vinegar. I used plain white vinegar from Wally World. You can use apple cider vinegar too as either one will get the job done.

12. Pour the vinegar in the tank along with a couple handfuls of pebbles and give it a good sloshing around. Do this every few hours until the rust and gunk is all broken loose. I let mine soak for several days. I would give it a good sloshing in the morning before work and when I got home.

13. When you feel like it has soaked long enough then fill the tank the rest of the way with water and let it soak for 6 to 12 hours.

14. Dump the vinegar/water mix out and pressure wash the inside of the tank. I dumped mine out and took it to a car wash. I did a soap and rinse to the inside of the tank until the rinse water came out clean. Make sure you get all the pebbles out!!! My tank looked spotless.

15. Here is an important step. Take a hair dryer or heat gun and completely dry the inside of the tank. Any residual moisture in the tank will cause it to immediately rust. If you are not going to install the tank then put some WD-40 or something similar to keep it from rusting.

16. Reinstall a fuel pump (new), fuel level sending unit, vent system and associated lines and hoses. I replaced all the hoses.

17. Disconnect the fuel feed, return and vent lines at the front of the car and remove the fuel filter. Blow out the lines with compressed air to make sure there isn't any garbage in them. Now is a good time to inspect the car's fuel lines and replaces the hoses.

18. Install a new fuel filter.

19. Push the harness and grommet up through the floor and reconnect the fuel pump and fuel level harness. Make sure the grommet is installed. Reinstall the rear seat.

20. Reinstall the tank.

21. Connect all the fuel feed, return, vent and filler lines.

22. Add a couple gallons of gas.

23. Reconnect the battery.

24. Turn the key to the ON position and check for any leaks.

25. If everything looks good the lower the car.

26. Start the car and check for leaks again.

27. If everything checks good the job is complete!

Good luck!!!

Last edited by High MX on July 14th, 2013, 2:35 pm, edited 2 times in total.

MR Bill
Elite Member
Joined: August 20th, 2010, 3:10 am

July 14th, 2013, 12:34 pm #2

Very good , I have a tank off right now and will try you way of cleaning. Thanks

Elite Member
Joined: May 25th, 2009, 2:59 pm

July 14th, 2013, 2:35 pm #3

Since you did all that it would be a good idea to seal the tank....
Eastwood Gas Tank Sealer

Remember 9/11. Never Forget.
The $ symbol goes in FRONT of the numbers, like so..... $30. NOT 30$. It makes you look stupid.
DISCLAIMER: All my posts unless otherwise noted or are blatantly obvious are my experiences with my car or past cars. Currently driving the '96 '98 Geo.

Constitution....what Constitution? obama

Elite Member
Joined: December 12th, 2011, 1:10 am

October 9th, 2013, 12:51 am #4

...Or just buy a new tank.

Elite Member
Joined: September 6th, 2010, 2:41 am

October 9th, 2013, 2:33 am #5

Something I did, when I swapped over to a GT/Turbo pump, even though I was using a pressure regulator that would keep the fuel pressure far below what the fuel line was rated for, I upgraded all of the rubber lines over to new injection rated hose. 100psi working versus 30psi(IIRC for these been a year or two since I did it) for what the stock stuff is. I also used it for all of the vapour lines, as while the outside of the lines looked fine, the interior was often cracked/crumbling.

Just an FYI, most all fuel line should be replaced every 5 to 10 years anyways, especially now that they are putting ethanol in the gas, and that stuff likes to eat rubber. Last thing you want is a line to burst while cruising on the highway, and you are greeted with a massive influx of heat from under the hood. :popcorn
Last edited by gamefoo21 on October 9th, 2013, 2:35 am, edited 2 times in total.

Joined: August 23rd, 2013, 11:21 am

October 18th, 2013, 1:11 am #6

0. wait til the tank is very near empty, if possible

alternate 3. back the back tires onto ramps. set the parking brake and otherwise ensure vehicle is secure

13.5 repeat 12 and 13 using ospho or other phosphoric acid or diluted muriatic acid solution. wear goggles.

alternate 15. rinse the tank out with a little ethanol or methanol, followed by a little gasoline. this will get all the moisture out