On side of Fuel Tank, what is it?

[Lazy-Ferret]

Since doing my body lift, I can see things that were not visible before. Most are good things, as it makes them easier to get too, but one thing has me puzzled, as I have never seen it mentioned on here.

Looking through the rear O/S wheel arch, on the side of the fuel tank, under the filler cap area, there is a small cylinder, where it looks like a fuel pipe goes through, one pipe into the top, one out the bottom of it. It;s about 2" high, and 1 1/2" diameter...

What is it?

 

[solarman216]

It is a check valve/breather that goes to the canister or air filter in engine bay the valve part comes into play if you put your motor on its side or worse as it stops fuel exiting down the pipe, Rick

 

[zippy656]

Can we have a pic please

 

[Lazy-Ferret]

Thanks Rick, so is it in the feed or return?

Can we have a pic please

I'll try and get one tomorrow, if it is not still raining..

 

[solarman216]

Thanks Rick, so is it in the feed or return?



I'll try and get one tomorrow, if it is not still raining..

No it is on the breather pipe that goes to the engine bay, tanks are no longer allowed to vent to atmosfere, they have to vent via a carbon canister or air cleaner to be burnt, Rick

 

[Lazy-Ferret]

No it is on the breather pipe that goes to the engine bay, tanks are no longer allowed to vent to atmosfere, they have to vent via a carbon canister or air cleaner to be burnt, Rick

So does that mean there are 3 pipes to and from the fuel tank, feed to filter, return from pump, and a breather, where does that terminate?

 

[AlexD333]

More knowledge thanks to rick again

C'mon lazy ferret get out in your dressing gown and snap us a picture (of the cylinder only) :naughty

 

[solarman216]

So does that mean there are 3 pipes to and from the fuel tank, feed to filter, return from pump, and a breather, where does that terminate?

Yes there are 3 pipes, never looked at the breather routing but think it might be on the near side as to the termination there are many versions, on the petrol there is usually a carbon granual tank about the size of a slim kettle but not all had it, on others it goes to a complicated valving arangment controlled by vacuum pipes but all ultimately end up in the lower part of the air filter to be consumed by the engine, Rick

 

[Lazy-Ferret]

More knowledge thanks to rick again

C'mon lazy ferret get out in your dressing gown and snap us a picture (of the cylinder only) :naughty

I would only take a picture of the cylinder... don't want to make you jealous...:lol

 

[Lazy-Ferret]

Yes there are 3 pipes, never looked at the breather routing but think it might be on the near side as to the termination there are many versions, on the petrol there is usually a carbon granual tank about the size of a slim kettle but not all had it, on others it goes to a complicated valving arangment controlled by vacuum pipes but all ultimately end up in the lower part of the air filter to be consumed by the engine, Rick

Oh no, another pipe for me to work out where it goes....

 

[AlexD333]

I would only take a picture of the cylinder... don't want to make you jealous...:lol

:clap good game sir, good game.

 

[Lazy-Ferret]

For Zippy and Alex... Pics

 

[AlexD333]

I will check and have a look at mine too. I presume by law I must have one too :augie

 

[solarman216]

OK just to clarify, this is the way it is on the petrol, there are variations, so I assumed it to be the same on the diesel but having looked it is not,

 

[solarman216]

This is a diesel tank complete with vent and arrestor, it actually goes to an inverted U with a funnel on the end clipped alongside the filler pipe, so does indeed vent to atmosphere, it must only be the petrol that that is not allowed, sorry for any confusion, it is simply not something I had been concerned with and so assumed, wrongly, Rick

 

[Lazy-Ferret]

OK, so now I am really confused.... Looking at your tank picture, have I got this right?

the large hole just visible on the top is where the sender unit goes, which has the fuel pick up and return built into it

The larger inlet on the side, is where the Fuel Filler joins the tank

The smaller in/outlet, by the filler hole is where the air that is displaced when you fill the tank, is vented up just inside the filler cap, so you can fill it with out getting splash back from air building up.

So the thing I was talking about, on the side of the tank, that appears to be connected to the very top middle of it, is what allows air back into the tank, as you use the fuel? I thought there was a valve in the filler cap to do that. Or is it to allow air to enter/escape when the fuel expands and retracts as it gets hot and cold when the car is parked up? Where does the other pipe to this go?

 

[solarman216]

Yes Clive you have it all correct, the valve contains a float so fuel seals it in the event fuel gets that far whether it be overfilled tank or vehicle on its side, to my knowledge there is no vent in the cap, certainly not on the petrol as it will hiss in or out depending on temperature when removing the cap, I will have to check the Diesel ones to see, the stub pipe on the valve in the pic goes to a short rubber pipe that fits to the bottom of as said an inverted U fixed to the metal filler tube in such a way that the top of the upside down U is above the top of the filler, and then just vents to atmophere, we had to have those little valves on intternaly mounted fuel tanks on Bangers so when, not if you rolled it no fuel leaked out, Rick