Gas tank cleaning
Thread Starter
Intermediate
Joined: Jun 2017
Posts: 40
Likes: 11
Gas tank cleaning
I recently inherited a 91 coupe,it was sitting for 6+ years. i had taken the fuel pump assy. off and going to replace it. The tank was half full of varnish at this point, the rubber and all the filter had all disintegrated.This are the steps i performed:
1. There is no battery in the car so i didn't have to disconnect the battery.
2. I removed the fuel door assy., then the boot. Then removed the fuel lines and electrical connector.
3. Upon removal of the fuel pump assy., i noticed the gas had turned to varnish, and pieces were floating around in it.
4. I removed the gas with a hand siphon(do not ever use an electrical pump).
5. I read somewhere(i believe in this forum) to use OXI-Clean to clean the tank. I went and bought some and placed about 5 scoops in the tank and filed with water and let sit for 6 hours. OMG this is a godsend!! after i pumped tank out there was no residue from the pieces of rubber or chucks from the fuel pump!! i would recommend this to anyone!! do not use any chemicals as the inside of the tank is painted(this is the liner). I used a terricloth towel to remove the small puddle of water left and put new fuel pump assy in. wow i did not need a new tank!!
i know this was probably covered before but i was overjoyed i did not have to replace the tank!!
1. There is no battery in the car so i didn't have to disconnect the battery.
2. I removed the fuel door assy., then the boot. Then removed the fuel lines and electrical connector.
3. Upon removal of the fuel pump assy., i noticed the gas had turned to varnish, and pieces were floating around in it.
4. I removed the gas with a hand siphon(do not ever use an electrical pump).
5. I read somewhere(i believe in this forum) to use OXI-Clean to clean the tank. I went and bought some and placed about 5 scoops in the tank and filed with water and let sit for 6 hours. OMG this is a godsend!! after i pumped tank out there was no residue from the pieces of rubber or chucks from the fuel pump!! i would recommend this to anyone!! do not use any chemicals as the inside of the tank is painted(this is the liner). I used a terricloth towel to remove the small puddle of water left and put new fuel pump assy in. wow i did not need a new tank!!
i know this was probably covered before but i was overjoyed i did not have to replace the tank!!
Pro
Joined: Aug 2007
Posts: 668
Likes: 38
From: Austin TX
After cleaning the tank, clear your fuel lines and fuel rails:
Install the fuel pump/sender unit into the tank and connect only the fuel pump hose and vent hose. Install a short piece of rubber hose to the return spigot into the tank and block it off. Before you install the fuel filter. Install a rubber hose on the fuel line where the inlet of the fuel filter is and put the other end of the hose into an empty gas can. Put a couple of gallons of fresh gas in the vehicles fuel tank. With the fuel cap slightly opened, turn the ignition switch "ON" as to energize the pump for a few seconds to clear that line with fuel into the gas can. Remove the rubber hose at the fuel filter location and install the fuel filter. Extend the rubber return line and drop the end into an empty gas can (away from the exhaust of course). Fire the engine and let run long enough to clear the return line with fuel into the gas can. Re-establish the return line to the tank and your good to go.
Install the fuel pump/sender unit into the tank and connect only the fuel pump hose and vent hose. Install a short piece of rubber hose to the return spigot into the tank and block it off. Before you install the fuel filter. Install a rubber hose on the fuel line where the inlet of the fuel filter is and put the other end of the hose into an empty gas can. Put a couple of gallons of fresh gas in the vehicles fuel tank. With the fuel cap slightly opened, turn the ignition switch "ON" as to energize the pump for a few seconds to clear that line with fuel into the gas can. Remove the rubber hose at the fuel filter location and install the fuel filter. Extend the rubber return line and drop the end into an empty gas can (away from the exhaust of course). Fire the engine and let run long enough to clear the return line with fuel into the gas can. Re-establish the return line to the tank and your good to go.
Advanced
Joined: Apr 2021
Posts: 85
Likes: 6
From: Northern Neck Va
Well.. I am in the process of figuring out the best way to clean my rusty gas tank. First off, we C4 owners should consider ourselves very thankful that we can do this without having to drop the tank! That is awesome.
Secondly, better think twice about using OxiClean to remove the rust. In the process of trying to figure out the best approach for chemicals, and was going out to buy the Oxiclean to do my gas tank with, I found this message. Link below message.
"OxiClean is not recommended for use on rust. Oxygen is a major ingredient in OxiClean, and an essential contributor to rust. Better to go with a product like Whink Rust Stain Remover to clean rust from metals and rust stains from fabrics."
https://www.apartmenttherapy.com/oxi...takes-36666388
Secondly, better think twice about using OxiClean to remove the rust. In the process of trying to figure out the best approach for chemicals, and was going out to buy the Oxiclean to do my gas tank with, I found this message. Link below message.
"OxiClean is not recommended for use on rust. Oxygen is a major ingredient in OxiClean, and an essential contributor to rust. Better to go with a product like Whink Rust Stain Remover to clean rust from metals and rust stains from fabrics."
https://www.apartmenttherapy.com/oxi...takes-36666388
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
This is an old thread should have started a new one. Best way to deal with rust in tank is replacing it. It this was something special where a tank wasn't readily available, there a products to clean and seal tank.
Advanced
Joined: Apr 2021
Posts: 85
Likes: 6
From: Northern Neck Va
Old thread but still shows up in a google search for C4 corvette rust in tank. The rust in the tank has killed 2 fuel pumps and going the rout of removing the rust and treating the tank. The car sat for several years before I bought it with bad gas and water in the tank. Just the bottom part of the tank is rusted, can definitely be saved. I can find a replacement tank but the labor getting a shop to remove it would probly be more that I paid for the car.
