Fuel tank breather maybe????

[nika Member Find all posts View Profile Close nika]

Saw this the other day and was wondering why its there, if its a breather for the fuel tank or over pressure release valve do we need to extend it like the diff breathers? It is located at the rear tank between the diff and tank.



any ideas people? Its a 120, 2004 model diesel.

[MickL Addicted PP Member Find all posts View Profile Close MickL]

Re: Fuel tank breather maybe????

Looking at ToyoDIY it seems to be this part no; 90917-10092

Listed as; Valve, check (for main tank)

It's shown to be teed off a pipe running between the two tanks.

Someones gonna have to take it off and see if it lets stuff in or out :!:


Mick

[Matty80 Avid PP Poster! Find all posts View Profile Close Matty80]

Re: Fuel tank breather maybe????

Saw this the other day and was wondering why its there, if its a breather for the fuel tank or over pressure release valve do we need to extend it like the diff breathers?

Seeing as your mentioned it Nick, looks like you'll be the guinea pig on this one, so when you going to pull it out for a look?

[nika Member Find all posts View Profile Close nika]

Re: Fuel tank breather maybe????

Looking at ToyoDIY it seems to be this part no; 90917-10092

Listed as; Valve, check (for main tank)

It's shown to be teed off a pipe running between the two tanks.

Someones gonna have to take it off and see if it lets stuff in or out :!:


Mick

Well others were sucking and blowing on diff breathers that were removed in the quest to help out PP members, guess what I will be doing tomorrow, bugger! Oh well might save me gettting water in the fuel so all is good, will report back later.

[nika Member Find all posts View Profile Close nika]

Re: Fuel tank breather maybe????

Ok in the interest of science I mean PP, took it out



and seperated it to see what it was all about



The verdict is, when you suck on it (tastes like sh1t) it free flows meaning air can freely flow into the fuel tank, blowing is restricted but only slightly.
Now I have to work out where I'm going to extend it to, like we do to diff breathers, possibly to the refueling point?

[AJ120 Out of control poster! Find all posts View Profile Close AJ120]

Re: Fuel tank breather maybe????

Just went out in the dark and crawled under the Prado with a torch, the D4D has the same breather. Given the amount of very deep water we took the Prado through on our recent Cape York trip i guess it is not a real issue. Having said that water and common rail diesels don't mix so given that it looks like a fairly easy job to extend it, I think i will just to be sure. Thanks Nick.

Cheers Andrew

[MickL Addicted PP Member Find all posts View Profile Close MickL]

Re: Fuel tank breather maybe????

Bit of further research seems to show this is diesel engined models specific. Looks like on the petrols this line runs all the way to the charcoal canister.

Someone with a petrol Prado want to confirm please?


Mick

[nika Member Find all posts View Profile Close nika]

Re: Fuel tank breather maybe????

It's shown to be teed off a pipe running between the two tanks :!:

Yes this is correct, would love to know if the petrol models have the same setup and if others have had water in the filter after crossing deep water. As I said earlier it allows air to enter freely into the tank but has a "slight" and I use the term lightly, slight restriction when bowing into it (meaning, allowing the tank to relieve pressure) maybe 1 or 2 psi of pressure(dont quote me as I havent tested it with a guage )

[Matty80 Avid PP Poster! Find all posts View Profile Close Matty80]

Re: Fuel tank breather maybe????

Sounds like another one added to the list for once i'm home again! Thanks for the info fellas...
Just a case of where to run it too - i'd be thinking the refueling point also mate, it seems the logical place for a "fuel tank breather"

Will you be using the same toyota fitting at the end of the extended hose? Or replacing for different type such as like what most have done for the diff breathers?

[nika Member Find all posts View Profile Close nika]

Re: Fuel tank breather maybe????

I think I will use this bit (original part)



to extend the line to a point away from water and add some sort of filter, or put a fuel filter where the breather lived and use the breather as a end piece where the line terminates. That way the tank has the factory fitting on the end and it keeps the design specs. incase we miss something. Need to think about this one.

[Schaffer Addicted PP Member Find all posts View Profile Close Schaffer]

Re: Fuel tank breather maybe????

Ok in the interest of science I mean PP, took it out



and seperated it to see what it was all about



The verdict is, when you suck on it (tastes like sh1t) it free flows meaning air can freely flow into the fuel tank, blowing is restricted but only slightly.
Now I have to work out where I'm going to extend it to, like we do to diff breathers, possibly to the refueling point?

What happens when the black cap is on? Can air pass through it at all or does that seal the white piece?
The reason I'm asking is in the TOYODIY.COM site it looks like they call it a check valve?
http://www.toyodiy.com/parts/p_G_200...Q_7751.14.html

Parts are listed as 77701T - Valve, Check (from Main Fuel Tank) (Assume this is the white peice) and 77135 - Bracket, Check Valve

[nika Member Find all posts View Profile Close nika]

Re: Fuel tank breather maybe????

The suck/blow test was done with it assembled and yes, air does flow in both directions as per my previous post, now to do something about it.

[Bushbasher Out of control poster! Find all posts View Profile Close Bushbasher]

Re: Fuel tank breather maybe????

The suck/blow test was done with it assembled and yes, air does flow in both directions as per my previous post, now to do something about it.

Air is one thing but water is another. You've shown that air at low pressure can flow either way but what about fluid. It may be designed like those old fashioned snorkels we used as kids - the one with the bend at the top and a ping-pong ball in a cradle. Would allow air to move freely but water would cause the ball to close off the pipe and prevent you from sucking in a gob full of sea water.

We can happily allow air to enter the tank but the valve may prevent entry or leakage of water/diesel?

[Matty80 Avid PP Poster! Find all posts View Profile Close Matty80]

Re: Fuel tank breather maybe????

We can happily allow air to enter the tank but the valve may prevent entry or leakage of water/diesel?

I suppose it would be safe to assume that the plastic valve has the potential to become jammed in the 'open' position for one reason or another and that in such a case it would have the potential to allow water into the diesel tanks (is it the same or different for petrol?)... I realise that there are lost of mights and maybes and possiblies, but it could still happen! the same reasoning realistically went into the thoughts for the other breathers.

Now that I know about the "potential issue" and now that it has been shared, I'd say its probably best to be along the same lines "as better safe than sorry"?

On the other hand of course, we don't actually know if we have a problem with this until our warning light comes on - and in that case would we even attribute the water/muck level to a possible entry point, or just put it down to dirty fuel?

EDIT: Corrected (some of) my spelling/grammer errors... Must be tired!

Matt

[nika Member Find all posts View Profile Close nika]

Re: Fuel tank breather maybe????

got some 1/4" ID fuel hose and extended the "breather" upto the filler neck, in total a 10 minute job using 1 meter of hose and a eye full of dirt.



I used the same breather to terminate the end of the hose

The suck/blow test was done with it assembled and yes, air does flow in both directions as per my previous post, now to do something about it.

Air is one thing but water is another. You've shown that air at low pressure can flow either way but what about fluid. It may be designed like those old fashioned snorkels we used as kids - the one with the bend at the top and a ping-pong ball in a cradle. Would allow air to move freely but water would cause the ball to close off the pipe and prevent you from sucking in a gob full of sea water.

We can happily allow air to enter the tank but the valve may prevent entry or leakage of water/diesel?

I understand what your saying, if you have one fitted then remove it and have a play and you will see what I mean