Help me replace the fuel tank...

[Kroggers]

It is winter, so time to do all the fixes and upgrades on the Boxster racing car

One thing I have to replace is the fuel tank in my Boxster S (2001), as it sustained some damage during the 2011 season.

I am trying to get the old one out and the new one in with as little effort as possible, and without having to remove EVERYTHING from the front of the car!

Anyone here got any experience with getting the fuel tank out on a Boxster and can give me some good tips and advice on how to best do this project?

[Kroggers]

I should probably change the title to this thread to "WARNING: react fast if your fuel tank is not releasing pressure properly"

My Racing car had some venting problems during the season that I did not look into good enough, and now that the car is up on a lift and ready to be sorted out - it would look like the problem was actual a lot bigger than I thought. This does not look to good!!!

[dad911]

Good time to remove those heater lines behind the tank. I 'dropped' mine just enough to get the heater lines out, it was a royal pain.

Edit: It doesn't look creased, I wonder if it would pop back out if you pressurized the tank somehow?

[Kroggers]

Originally Posted by dad911

Good time to remove those heater lines behind the tank. I 'dropped' mine just enough to get the heater lines out, it was a royal pain.

You can see in one of the pictures that we just cut the heater lines when the car was converted to a dedicated racing car. When I have the tank out I will do anything else relevant whilst i have the access - forgot about theater lines, good point. Thank you

Originally Posted by dad911

Edit: It doesn't look creased, I wonder if it would pop back out if you pressurized the tank somehow?

I have been thinking the same thing, but not sure how I would seal the tank to be able to pressurize it properly (and safely). I can use my compressor to pump air into it, but how do I seal it properly to make sure it gets properly pressurized?

Any ideas?

[howe00]

Dont use air to pressurize,very dangerous, water could be a safe option, any relatively easy.

[Kroggers]

Originally Posted by howe00

Dont use air to pressurize,very dangerous, water could be a safe option, any relatively easy.

I would need some more info here - how would I pressurize the tank with water?
How do you suggest I do this? I will assume I fill up the tank with water, but then what?

[Dale_K]

I read a thread just like this once but I can't remember where. It was at a dealer and they saved the tank somehow. I think there are vacuum control devices in the plumbing but I don't know how they work.

Please carry on with the thread as you work on the car.

[healthservices]

Dry Ice?

Use at own risk! This is just an idea. use what ever safety precautions nec

If the tank is soo sealed right now, drain tank of as much fuel as you can.

drop several (a lot I would think at least a 2 pounds) crushed dry ice (solid carbon dioxide) cubes into the tank.

close cap.

keep a careful eye on the tank.

as soon as the tank is bloated back up open cap and leave off until tank is at room temp. This can take several hours depending on how much dry ice is still in the tank.


And yes if you just leave the cap on and walk away the tank will explode! so keep a close eye on on it!

After tank has resumed shape and ice has evaporated, check all lines to make sure none have popped off due to the pressure.

After the dry ice is melted (turned to gas) you should be able to just put gasoline in, as the tank is not contaminated

Note: Dry ice (solid carbon dioxide) is non flammable and considered inert in the gas tank. It changes from solid to gaseous state without becoming a liquid when in the form of dry ice.

[dad911]

I would not use an air compressor, or anything with a motor that could spark. Perhaps a hand pump, and go gently, a few pounds at a time to see if it will work. I'd guess very little pressure would be necessary.

With water you'd need to remove the fuel pump, wayne has the procedure online here: Pelican Technical Article: Boxster Fuel Pump Replacement - 986 / 987

With either method I'd remove any senders and plug all of the lines.

I looked in the factory manual and did not see the procedure for removing the tank. I seem to remember dropping the sway and front suspension a little in order to drop the tank and get out the water lines. It was a pain, but fairly straightforward.

[Kroggers]

My current plan looks something like this:

The tank has already had all the fuel drained out - that was one of the first things I did, and since then (about two weeks ago), has been siting open.

I do worry about it exploding as the garage is in the basement of our house, and I do not want the house to go up in flames!

I actually do have a replacement tank that I purchased used from a parts supplier here in Finland, but after it was suggested to me by a friend i thought I would investigate the option to fix the tank. The process to remove the tank is not a simple project die to how it is sitting in the car. I have to drop the complete front end including the power steering, cooling system and suspension to get the tank out - so if it can be fixed whilst still in the car it will make the job a lot easier

I am undertaking some other jobs at the same time, so the car is now on the lift and can not be moved due to me not having the option to fit one of the rear wheels at the moment!

Here is my current thinking based on all the comments - what do you think to this approach?

1.- Fill tank with water (this will probably damage the fuel pump, but I have a replacement and the current one is jammed between the buckled bottom and the top of the tank!)

2.- Seal the tank and the slowly compress it with air - I have been suggested to try a hand pump to start with rather than air from my compressor.

3.- If it is proving stubborn, I will put a halogen lamp under the car (tank) to radiate some heat at the dent.

4.- Once the dent is out, I will drain the water out from the tank and leave it open to dry out completely.

5.- Should this not work out, then I will have to drop the tank and replace it.

Am I correct in assuming that filling the tank with water will reduce the risk that it will go up in flames and reduce the amount of compressed air required to return it to original shape?

Does this sound like a good plan?

[Kroggers]

Much better



Some heat under the tank and compressed air administered slowly, fixed the problem...

Now I have a spare Boxster fuel tank that I am not sure I will ever need

[dad911]

Great! Now how about some details.....?

How did you plug the lines? How did you apply air? PSI, etc....

[Kroggers]

Some details....

When the tank collapsed it completely damaged my fuel level sender and as such I had a spare one to play with. I permanently blocked all the holes in it apart from on (the one that feeds the breather system and charcoal canister - this gave me a perfect fitting cover for the top with just one hole in it where I could pump the air in.

I put a large halogen lamp under the tank and turned it on to give some heat to the tank - this was to help soften the plastic just a little bit - remember my tank was empty when I did this

I then turned down the pressure on my compressor as much as possible and proceeded to pump compressed air into the tank with short bursts. I kept about a 5 sec gap between each burst and had a close look at the bottom of the tank. It only took about 5 bursts for the tank to slowly start returning to normal shape.

[howe00]

Sorry for the delay in getting back to you, but for the future, fill the tank with water, close all orifices, then use a old hydraulic jack or similar, connect to any inlet pipe etc and just pump.Its safe because you are not using compressed air, purely hydraulic prerssure,not potential energy stored, if it lets go all you get is a leak. ---- cheers