Hi Everyone, I have a '92 4.0L 4WD Larado, this is my first post..
Finally getting around to getting my '92 XJ back together and running, I pulled the tank because the fuel pump literally melted...
So this meant dropping the tank to fish out the rest of the fuel pump parts and whatever other trash was in the tank
See all that white stuff? It's flaking off the inside of the tank, it seems like some kind of polyethylene coating which has degraded in the rancid gas
My question -- what to do about this? It's on in some places pretty well, and nothing I've found can dissolve it away. I could try and power wash it out but that's only going to go so far as I can't access the tank entirely.
As I said, I tried dissolving it in everything I could think of and nothing touched it, I ended up burning a small pile of it and it smelled just like polyethylene burning (anyone that's ever done a rope knows the smell well).
a) do nothing, as the new fuel pump has a strainer
my tank is out to replace a failed FP, and its not great inside either...they never are
b) coat the whole tank inside with POR15, which will work, but if there is any existing flaking coat, it wont adhere...fuel tank "coatings" are rusky in my opinion
Have heard of a dude recently damaging his newly rebuilt expensive engine cause the in tank fuel coating jammed some valves
c) using external heat on the tank, see if that will cause the internal coating to "peel off"
This is also not without risk, as using naked flame near even an empty tank runs the risk of an explosion due to fumes. You must wash it out many times with detergent and water first
If I had a bit more time and inclination, I would insert a drain bung in the fuel tank
corrosion in the fuel tank is an everlasting problem on older vehicles, moisture in the air gets in the tank, does its evil work
A hot dip done commercially might work. they can often boil out gasoline residues, and even tank liners.
A pressure washer with the correct nozzle should be able to access much if not all the inside. Test if a pressure washer works, if it works in a test, then buy or fabricate a nozzle and or wand that will access all the inside.
Thanks all, I ended up cleaning it out with a shop vac then I set it out in the hot sun, after that I poured some concentrated degreaser, washed well and then I blasted away with the power washer and managed to knock nearly all of it off, rinsed a few times and while still in the hot sun, focused a heat gun into the filler port, it got the whole tank up to 170 degrees and totally dried it out without flash rust. One more vacuum to get the last bit of trash out I painted the rusty spots (minimal) with some good old black Rustolium before reinstalling everything.
Next on the list is a new radiator, but hey it starts and runs now
