GX tanks can't be reused?

[allpro]

I have a GX with some body damage that will require removal of the tank as a precaution (the tank was not damaged). So I found a mechanic with the factory GX manual with procedure to remove the CNG tank. But it says that once the tank is removed, replace it with a NEW one! This can't be right.

So according to Honda, there is no such thing as a used tank, that once it's removed, it's compromised. I'm sure someone has re-used a tank with no problems. If this is true, why? If not, why would they say that?

[freedml]

Re: GX tanks can't be reused?

CYA and/or sell more $6k tanks...

[karlhafen]

Re: GX tanks can't be reused?

I have read that in the 2001-2005 and 2006 GX supplement. It sounded strange to me too. The only reason I can think of is the factory procedure calls for you to manually drain the tank completely. I understand that draining a type 4 tank completely is rough on the tank liner. I wonder if running the tank down ONLY till the car stopped running would be a better idea. Any Lincoln experts know for sure?

[siai47]

Re: GX tanks can't be reused?

I didn't think that the 2006 and newer GX's used type IV tanks. If thats true there must be another reason (in Honda's mind) as to why the tank must be replaced. Maybe they just mean that after you remove the tank you must re-install it .

[larrycng]

Re: GX tanks can't be reused?

There are some good comments. I, not being a lincoln expert, would recommend venting the tank down to around 100 psi to make sure the liner stays inflated. I have heard about problems with the liner collasping, no hard evidence. Besure to snug down the manual lock off on the cylinder valve and post a note indicating there is still pressure in the tank.

Have the cylinder inspected by a certified cylinder inspector. Pay special attention to the area around the cylinder and make sure the tank has not received any impact. Also check the "witness marks" on tanks to see if there is any movement. And be sure to follow Honda's instruction tightening the cylinder mounting straps in the brackets - thery are spring loaded. If everything is good, put it back in service. I also believe the Honda is doing a CYA.

How about it Curtis, any comments ??

Larrycng

[karlhafen]

Re: GX tanks can't be reused?

From the 2006 GX supplement section on removing the tank: This procedure degrades the integrity of the fuel tank. If you do it, do not reinstall the original fuel tank. Install a new one.

That being said. The tank remains clamped in it's frame during removal. I cannot imagine anything other than the venting that could injure the tank.

[Franz]

Re: GX tanks can't be reused?

The clamps place compressive stress in two localized areas. When the clamps are removed, the area which was previously stressed is now relaxed, even if there is no fuel in the tank.

Composite tanks are excellent in resisting expanding stress but not so well in compressive stress.

Honda is certainly doing a CYA, but they are the ones who will bear the blame if a tank failed. They are being conservative.

Franz

[larrycng]

Re: GX tanks can't be reused?

Thanks Franz, hadn't thought about that aspect. It always best to follow the the factory recommendation, even if they are CYA

Larrycng

[Highmarker]

Re: GX tanks can't be reused?

CYA and/or sell more $6k tanks...

FYI, I looked into replacing the tank on a Chevy Cavalier and the dealer quoted me $3k (this is a Type II tank).

[allpro]

Re: GX tanks can't be reused?

There are some good comments. I, not being a lincoln expert, would recommend venting the tank down to around 100 psi to make sure the liner stays inflated. I have heard about problems with the liner collasping, no hard evidence. Besure to snug down the manual lock off on the cylinder valve and post a note indicating there is still pressure in the tank.

Larrycng

So what would be the best way to vent the tank? The shop believes that can be done by letting the engine run till the pressure is insufficient and it shuts off, then close the manual lock off on the tank.

The clamps don't have to be removed, the whole assembly comes out when the rear seat is taken out.

[Curtis]

Re: GX tanks can't be reused?

Franz. thanks for the input, but it begs the question of reuse of used cng tanks in general. Most used tanks have been removed from their straps, heck, some have been dragged around on the ground due to their sheer weight.

If the decompressive forces are an issue... are some types/makes of tank more inclined to failure than others if reused after removal?

Frankly, I imagine that Honda wants to preclude any type of a potential failure possibility. I know I would, if I were them. Lives are the most important thing here. Even if the risk were very low, as it may be, zero is always a better number when talking about the alternative.

Are used tanks more inclined to failure, even if not damaged, and even if CSA certified for reuse?

[freedml]

Re: GX tanks can't be reused?

Let's not forget the initial question. Removing and reinstalling an undamaged tank from a GX so body work can be done. As long as you don't "drag the tank around on the ground" while it's out I don't see any safety issues with that.