Section : Fuel and Additives

Petrol smell coming from the boot

Posted By : Damian Pearson, 09-Dec-2003, 09:18am

Hi,
I wonder if you can help me? I have just bought a spitfire 1500 and it seems to have an excessive petrol smell coming from the boot. I have had a quick look and can see no leek coming from the petrol tank.
As the vapours seem to be seeping into the cock pit it is starting to concern me.
The question is this.
Is this normal?
If not is their anything I can check?
Many Thanks,
Damian.

Followups :

Petrol smell coming from the boot

Posted By : Michael Davis, 09-Dec-2003, 10:50am

The usual cause of this is the little rubber cover on the (redundant) fuel tank breather having perished or being missing altogether.

Have a look on the top of the tank. There should be a pipe coming out to feed the engine and another little stubby pipe with a cover over it. That connection is not used on a Spitfire 1500 so it is blocked off but if it's not [blocked] then fumes will get into the car.

Probably worth checking the rubber bits of the other pipe too whilst your in there. And remember that petrol vapour is potentially explosive! No smoking etc. etc.

Any other suggestions?

Mik
- Petrol smell coming from the boot
  
  Posted By : Mark Stradling, 09-Dec-2003, 11:40am
  
  Does anyone know if the breather 'bung' is available from anywhere, or something that is the correct size?
  
  Mines been missing for ages (perrished) and I should really replace it! ^_^
  - Petrol smell coming from the boot
    
    Posted By : Michael Davis, 09-Dec-2003, 12:00pm
    
    I'd guess at a short length of petrol pipe, an even shorter length of wooden dowel and a couple of hose clips.
    
    Make your own, Blue Peter style
    
    Mik
    - Petrol smell coming from the boot
      
      Posted By : Michael Bird, 09-Dec-2003, 01:04pm
      
      I might be wrong, but I don't think you should just block this vent up. The 'bung' that is referred to was I think actually a one way vent - air in but no fumes out. Therefore, if you block it up and your fuel filler cap doesn't vent properly, you risk pressurising the tank. I have always thought it safer when the thing perishes, to run a long length of fuel pipe from the tank, to the underside of the car, (their is a blanking grommet in just the right place to do this!). It makes senses to ensure this doesn't then drip fuel onto the exhaust and completely elimantes the smell.
      Hope this helps!
      Michael.
      - Petrol smell coming from the boot
        
        Posted By : Mark Stradling, 11-Dec-2003, 10:25am
        
        The origonal 'bung' was a all rubber thing like... a tyre valve dust cap, but in 5mm thick rubber. This slipped over the short vent pipe and was secured with one of those metal bands you can squeeze open with a pair of pliers.
        
        I don't see how this could ever have vented and, at a guess it was not used on UK cars, but part of the US emissions stuff (or similar).
        
        Will be giving the blocked length of fuel hose solution a go my self.
        
        Petrol smell coming from the boot
        
        Posted By : Damian Pearson, 11-Dec-2003, 10:57am
        
        Thanks Mark will do.
        
        Petrol smell coming from the boot
        
        Posted By : Paul Bodiam, 12-Dec-2003, 10:56am
        
        Is the fuel filler cap vented on a Spitfire? If not, then how does air get into the tank to replace the fule being sucked out by the fuel pump?
        
        When I stripped the fuel tank out of my spitty for restoration (3 years ago - must get round to finishing it soon) it had the rubber dust cap thingy that Mark describes, but I seem to remember it had a small cross-shaped piercing in the end - presumably to allow air in to the vent.
        
        Petrol smell coming from the boot
        
        Posted By : Mark Stradling, 12-Dec-2003, 02:10pm
        
        The cap on the Spit. was almost always vented on the Spit. (http://www.rimmerbros.co.uk/cgi-bin/rimmer?spitfir...).
        
        At a guess the cross in your plug was either some hack for a faulty filler cap or just freakie perishing of the rubber.
        
        Petrol smell coming from the boot
        
        Posted By : Paul Bodiam, 12-Dec-2003, 02:36pm
        
        Hi Mark
        
        The link that you posted to the Rimmers website provides some interesting food for thought. On that page it states:
        
        "Mk1, Mk2 & Mk3 fuel tanks were originally vented through cap."
        
        ...and also:
        
        "MkIV & 1500 fuel tanks have a breather vent in top of tank. "
        
        It then lists two sorts of filler cap for the Mk IV/1500: vented and unvented (although the unvented cap is now unavailable).
        
        Having said that, I have just been out to my garage and checked:
        my filler cap (from a '77 1500) is vented, and the breather cap does indeed turn out to be a bodge from a previous owner: someone has carefully drilled a hole down the centre of a philips-head screw, and then screwed this into the breather cap! I cannot imagine what problem they thought they were solving by doing this!
        
        cheers
        Paul
        
        Petrol smell coming from the boot
        
        Posted By : Stephen Airey, 15-Dec-2005, 07:37am
        
        A message from a long time ago - but I now have a similar problem.
        
        My question is - how can you tell if you filler cap is the vented or non-vented type for the 1500?
        
        Petrol smell coming from the boot
        
        Posted By : Julian Saul, 15-Dec-2005, 10:16am
        
        The rubber seal sealing off the bottom of the cap to the tank has no ventilation opening in it (hole in centre), and the cap itself has a hole through the core allowing ventilation to atmosphere.
        
        Petrol smell coming from the boot
        
        Posted By : David Rumens, 13-Dec-2003, 04:40pm
        
        On the 1500 Spit fuel tank there is an extra pipe next to the normal fuel feed pipe on the top of the tank.
        
        This extra pipe is only used on the US market, it is part of the emmission control set-up. On UK cars this should be blanked off with a rubber cap. The rubber cap fails after a number of years and then allows the fuel tank to vent into the boot. This is normally the problem with a petrol smell in the boot or when you are driving with the hood up. It should be the first thing to be checked.
        
        Replace the blanking rubber cap and all will be well.
        
        Regards
        
        Dave
    - Petrol smell coming from the boot
      
      Posted By : Philip Wright, 09-Dec-2003, 01:59pm
      
      I made my own using a short length of rubber fuel pipe and filling one end with some silicone sealant. Simple, yet effective - well, its lasted a year so far!
      
      Phil
      
      '74 Spit - Top Down
      - Petrol smell coming from the boot
        
        Posted By : Damian Pearson, 11-Dec-2003, 09:14am
        
        Many Thanks will give that a go.
Petrol smell coming from the boot

Posted By : Christopher King, 09-Dec-2003, 10:52am

Have you checked the seal around the sender unit in the tank (behind the cover in the boot)? And the collar going up to the filler cap? The rubber on these two seals can perish fairly easy...
My spitfire smells a bit of petrol / oil/ gaskets , and I guess this is normal in any old car. However you might want to get someone to look it over, it just needs to drip onto the exhaust pipe..

Good luck

Chris