Jump to content

Fuel tank gurgle!


Walshie

Recommended Posts

Walshie

Hi all,

I could use your advice please.

Did about 120 miles today - ran great, no issues. Went into the garage this evening- about four or five hours since car was parked. 
 

I noticed an occasional gurgle. Took me a minute to figure it was coming from the car!

 

I have noticed that there has always been a fair bit of pressure when I remove the fuel cap.

 

I took the cap off this evening and all quiet again.

 

Could this just be a simple breather blocked or is there anything else that I need to check?

 

Is there / should there be pressure in the tank when I fuel up? 
 

Grateful for any thoughts!

Thanks v m

W

 

 

 

 

 

Link to post
Share on other sites
TableLeg

There shouldn't be any pressure in the tank at all (other than atmospheric).

 

As you draw out fuel air should be allowed into the tank to equalise the pressure (usually via the cap itself). If this doesn't happen then you can create a negative pressure in the tank and this would be bad. Positive pressure could come on a hot day as the fuel expands if the tank had no means to vent the expanding vapours.

 

Check your filler cap, it should have a vent hole in it. If by opening and removing the filler cap you hear the hiss as air is drawn your vent is most likely blocked.

 

 

Link to post
Share on other sites
pistonbroke

A lot of cars have none breathable filler cap (mine included ) Instead we have a vent tube fitted at top of tank , this should have a safety valve fitted in case of inversion + a fire gauze filter in circuit , worth checking if all is good there .

Link to post
Share on other sites
Walshie

Hi,

Thanks, where does the vent tube vent to?

 

I have a cap which has a lever which needs to be flipped up, then a quarter turn. Looking at it, it appears to have an O- ring which is sealed by the lever action - so can’t see how this is vented.

 

Thanks,

W

Link to post
Share on other sites
Dave Eastwood (Gadgetman) - Club Secretary

It’s age dependant with Westfields, but it sounds like your car may be the current style, if it is:
 

The roll over valve is normally screwed into the top left of the tank, with a hose coming off and running upwards. (The route I’ll have been decided by the builder, typically it’s up the adjacent chassis rail, but you never know...

 

Depending on the type of hose used, it can kink and flatten, causing a blockage. The valves themselves can occasionally block in one direction, too.

Link to post
Share on other sites
Steve Smith - AO Hampshire And Isle Of Wight

I had the same tank pressure problem. I found that the breather hose was kinked. I repositioned the hose so that it smoother curve. Easy fix.

Link to post
Share on other sites
Beaker_Bob

I had similar problems with pressure in the tank, noticeable with a hiss when i refueled.

 

My tank has one of these screwed into the top left corner; Newton Roll Over Valve.

image.png.7ee04637163c1bd356763adb9e665955.png

There was no vent tube attached to the top of it and as a result, the two ball bearings inside had become sticky with fuel/general crud.  A clean in an ultrasonic bath and then refitted with a piece of fuel pipe and a pig tail (similar to the picture from Matt_S) has solved the problem with no re-occurrence.

  • Like 2
Link to post
Share on other sites
Dave Eastwood (Gadgetman) - Club Secretary

Please note, though if you ever need to replace these, you need a proper roll-over valve, not just a cheap one-way valve, that sometimes gets sold as roll-over valves.

 

A proper valve is a two way device, so will allow excess pressure in the tank to escape, but will also allow air in to prevent a partial build up of vacuum. They only "close" when the pressure trying to escape gets high enough to mean its fuel, not just air.

  • Like 1
Link to post
Share on other sites
Walshie

So, the plot thickens!

Roll-over valve in top of tank, hose running up and away from this, just as suggested.

The hose runs up the chassis rail for about 7-8 inches and then is turned back on itself.

Doesn't appears crimped or constricted in anyway. <Might have to remove the valve to check it out and be sure its ok.

Thx

W

Link to post
Share on other sites
Dave Eastwood (Gadgetman) - Club Secretary

The valves can gum up internally, as Rob said...

Link to post
Share on other sites
pistonbroke

should be able to gently blow down it both ways ( OO Errr missus ! ) :love:

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

Please review our Terms of Use, Guidelines and Privacy Policy. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.