Fuel smell

[oliver90owner]

Usually if the vent is blocked fuel starvation will happen, 

Agreed, but there are known cases where permanently open holes become non-return valves, so worth checking out. Flexible brake pipes are one example and, in the opposite direction, fuel lines are another.

RAB

[JOWETTJAVELIN]

Hot weather makes petrol expand and if you have a full tank it can come up the filler pipe and overflow.

[biomed32uk]

I am pretty certain its the filler neck hose, the silicone one I fitted seems to have gone porous if thats possible, if you rub your hand over it and take it away your hand will stink of fuel.

I neck the tank last weekend and there is no trace of fuel around the sender or its screws.

Have to try a piece of hose listed as filler neck hose. Other problems to deal with at the moment as I got the smell of coolant yesterday !.

[biomed32uk]

It's been a busy couple of weeks, with work plus sorting the heater valve out overtook this one.

However I ordered some Mocal filler neck hose of a suitable size from Demon Tweaks, and fitted it on Friday.

So far no smell of fuel, the silicon hose I had fitted certainly smelt of fuel on the outside, but didn't look like it had been attacked. That was fitted last summer when I replaced the original hose that had rotted badly and become porus.

Hopefully it will now be a smell free car, I did also replace the sender gasket last summer and the new one when fitted did get a wipe of hylomar.

[biomed32uk]

I can confirm that this was down to the fuel filler neck pipe.

No more smell of fuel at all after fitting the 'Mocal' hose for the last couple of weeks.

The silicone while not actually leaking is porus enough to let fuel vapourise through, and a little goes along way to making a smell.

Job sorted !

[biomed32uk]

Just a further update to this the filler neck hose did resolve most of the smell, however when filling right up the smell was coming back, going away once the tank run down a little.

Had a look with the tank necked and a nice pool of petrol in the top of the sender, sneaking up past the screws as suggested. A coat of loctite 577 thread sealant, which is unleaded fuel resistant has sorted that out.

100% finally sorted now, once and for all !.

[Declan_Burns]

I have since made up the sender seal in Viton as I have a CNC cut template and will be testing it as soon as I am fit enough to get back working on the cars.
Regards
Declan

[biomed32uk]

Be interested to know how that works out Declan, sure it will be excellent as per all your other seals etc.

[svenedin]

I know this is an old thread but it seemed pointless to start another one.

ESM replaced my fuel tank complete with new sender unit in November 2022 and also the filler tube hose (they used rubber hose).

I have noticed a stink of petrol in the boot which is now worse in the warmer weather of Summer.

I think I might try the Mocal fuel hose or I see Holden sell an fluorosilicone lined hose for the filler tube. It seems from this thread that the ordinary silicone option is not good.

I have some Permatex and I can seal the screw threads that secure the sender.

Does anyone know whether the Viton fuel sender gasket is available?

Regarding hose, I fitted some quite expensive fuel hose between the fuel pump and the carburettor. Whatever I did it would ooze where it joined the carb and the fuel pump and I could smell that fuel. I have now changed to "Gates" brand ethanol resistant hose 1/4" ID from Moss. This is really expensive but so far so good, no leaks and no petrol smell in the engine bay.

Stephen

[paul 300358]

Try tightening the sender unit fasteners, but be aware that you can overtighten them which crushes the gasket. Also you do not need any sealant with a cork gasket.

[mowogg]

I had this issue for many years. After changing gaskets to viton and thr filler hose I eventually realised it was coming from the cap. Fuel was evaporating and running back down on the outside of the filler flexis line back into the boot. Obviously not very much but it does not need to be to get a smell every time you open it.

For me a new seal in the cap (viton) and adjusting the air hole in thr filler adapter solved it. The latter needs to be at the top to stop fuel running back

[svenedin]

I had this issue for many years. After changing gaskets to viton and thr filler hose I eventually realised it was coming from the cap. Fuel was evaporating and running back down on the outside of the filler flexis line back into the boot. Obviously not very much but it does not need to be to get a smell every time you open it.

For me a new seal in the cap (viton) and adjusting the air hole in thr filler adapter solved it. The latter needs to be at the top to stop fuel running back

Excellent but where to get the Viton seals. Irrelevant perhaps but pressure lamps and stoves I rather like and have a collection of. Viton is a revelation

[mowogg]

I made the one in the cap from flat sheet copying theold one.

[mowogg]

I made the one in the cap from flat sheet copying theold one.

[svenedin]

Ah I see. I am not sure I could make a gasket well enough but I will probably have a go.

I investigated the gasket today. I chose a bad time to do it as the tank was full so I drained a bit out of the tank and fitted a new, greased cork gasket with some Permatex on the threads of the screws. The screws have both a slot and a 1/4" hex head so they can be tightened down with a socket.

All seems better, for now at least. The problem is that anything that has had petrol on it stinks for ages afterwards. It is hard to tell if the problem is fixed.

Oh and point noted about the filler cap which definitely needs a new gasket.

Stephen

[svenedin]

I have not cured this issue yet. Still a horrible smell of petrol every time I open the boot. I will try to get a sheet of Viton and make a new gasket for the petrol cap as previously suggested. I am also going to try to make a Viton fuel sender gasket. I could find no leaks in the pipe from filler to tank but I replaced it anyway with a silicone one from ESM and new jubilee clips too. This has made no difference at all. I just don't think the cork gasket on the sender is up to the job. The Federation of Historic British Vehicle Clubs lists cork as unsuitable as a gasket for fuel containing ethanol .

Stephen

[myoldjalopy]

The problem is discovering exactly where the leak is - and it may be very small. It is not unusual for Minors to have a bit of a petrol smell, especially after filling up - which suggests either the fuel sender gasket or the filler hose (hose itself, or tightness of the hose clips)
I have had problems with the sender gasket in the past. After fitting a new tank and fuel sender gasket I went to get petrol and after filling up and paying, a man pointed out I had fuel leaking from under the boot area onto the ground. This was cured by tightening up the sender screws but a while later the same thing happened again! So I tightened the screws up a bit more and it has been leak free ever since (about 15 years). Obviously there is a limit to how tight you can do the screws up before causing damage as a result.
I hope the viton gasket you intend does the trick.....

[svenedin]

Thank you. I replaced the filler cap gasket with another cork one but I don't think it's coming from there.

There are no obvious leaks from the sender area but of course vapour is clearly making it past somewhere.

Better weather is coming (we hope). It's nice to go out touring in a convertible but not so good when the picnic is tainted with petrol!!

Stephen

[svenedin]

I am waiting for a Viton sender gasket but they are out of stock. I could try to fashion my own with some Viton sheet if I cannot get a pre-made gasket.

I had a spare cork sender gasket so I investigated today. The old gasket (which is not old, only fitted months ago) had torn in two places. Perhaps I overtightened it but I remember being careful. Maybe it was not properly centralised or perhaps it is just too thin and fragile.

This time I fitted another cork gasket but with generous Blue Hylomar on both sides and extra goo for the screw holes. Then I went and filled the tank brim full. So far so good, no sign of any fuel seepage. The boot needs a good airing before I can judge whether the fuel smell is cured.

Stephen

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[Chief]

The boot needs a good airing before I can judge whether the fuel smell is cured.

Coffee or Bircarbonate of Soda/Baking Soda in a tray is meant to help remove odour quicker.

Funnily enough yesterday I re-discovered a bottle of Autoglym Odour Eliminator that I'd bought when I bought a much smoked in parts car many years ago. All I remember about it is it did nothing whatsoever in combating the cigarette smell while my attempts with Febreeze ended in failure since the places I used it became covered in mould.