Fuel smell

[biomed32uk]

I know this has been covered before, but my boot and the inside of the car when its been shut for a while always stinks of fuel.

The source is definately the boot, as that always smells, and obviously the tank is there.

The tank is sound, it was new 7 years ago and is spotless inside and out.

The rubber filler pipe was rotten but that was changed out last year so is all good and tight.

All of the fuel lines are good and sound, but they are outside the car anyway. If they were leaking the garage would stink of it.

I have changed the gasket on the sender, and at the moment the tank is only just over a 1/4 full, so it's not petrol sloshing around over the top.

Has anyone else been through this and found a cure, is it just fumes escaping past the cork gasket, a little petrol goes along was when making a smell of it.

[Budgie]

I have much the same problem so I'll be interested in what the forum suggests to .

[mogbob]

Simple first . The filler pipe , tight jubilee clips. I know it's new'ish but some rubber perishes quickly with unleaded modern fuel. Sniff test
and then move on.
No obvious damp patches on the tank exterior. Main seam still solid. A little talcum powder sprinkled around the perimeter might throw up
a slight "weep ". That's all it takes. If the powder doesn't stay dry you've identified the area.
The sender gasket , did it go in dry. I either lightly grease the gasket or use a light smear of gasket cement. Are the small fixing screws a snug / firm fit.... not sloppy. Again , a sniff test wouldn't any harm.
Let us know how you get on.
Bob

[BLOWNMM]

It is possible for fuel to make its way up the sender screw retaining threads and out under the screw head. Like you say it does not take much to create a smell. There was a post by Declan Burns where he resolved this problem in his MG TD which are apparently difficult to seal. He used a light smear of 'Reinzoplast' on the screw threads and plastic washers under the screw heads. I have attached a link to his post.
Bob
viewtopic.php?f=4&t=51027&p=483506&hili ... ng#p483506

[mogbob]

I'm a great fan of Heldite ( mentioned in the post that was flagged by my namesake ).
Bob

[BLOWNMM]

Further to my last post when the sender screws are fixed the upper side of the screw thread is tight against the upper side of the female threads. Because the thread has clearence there is a void between the underside of the threads which is helical. When the screws are fixed they penetrate into the fuel tank and petrol can be splashed on them. When this happens capiliary action (see link) can cause petrol to migrate up this helix until it reaches the under side of the screw head. The screws are usually fitted with spring washers or star tooth washers neither of which will act as a seal between the screw head and the sender body. Hence the petrol evaporating from the screws and causing fuel smels.
Bob
https://en.wikipedia.org/wiki/Capillary_action

[Declan_Burns]

There is a rubber gasket available for the sender unit. It is not cheap though and available from Peter Edney. Moss may also have it.
http://www.mg-parts.co.uk/index.php?rou ... uct_id=213
I also have an issue with the Moggy smelling of petrol. I have found the leak to be a pinhole just under the tank flange and as mentioned above it only takes a few drops and you can clearly smell it. If I don't fill over 3/4 full there is very little smell.
New tanks are quite pricey seeing that I am now retired I will try some JB Weld or similar.
Permatex Aviation grade sealant is also supposed to be fuel proof but I have always been happy with the Reinzoplast.

Regards
Declan

[BLOWNMM]

Declan
Would I be correct in assuming the rubber gasket you linked to, is suitable for the Minor tank sender?
Regards
Bob

[Declan_Burns]

Bob,
I would think so as it looks identical in shape but you would want to check the PCD. Here's a drawing of the TD low fuel sender and gasket. The T-Series cars did not have a continuous level gauge-but they soon will have the option.
Regards
Declan

[BLOWNMM]

Thanks Declan - I have a new Minor gasket to check the dimensions with.
Regards
Bob

[RobThomas]

viewtopic.php?f=19&t=64193

Modern version of the rubber hose but in Silicone.

[Declan_Burns]

Rob,
Silicone is not petrol resistant! I learned that the hard way. When I replaced the dreaded low fuel sender on the TD I used silicone. It was alright on the test drive so I thought it was a job well done and put the car back in the garage.
When I came out in the evening to go and meet my mates there was petrol flowing out under the roller shutter door! I was glad nobody dumped a cig butt in the drive.
It wasn't just the silicone but there was also an issue with the wrong screws supplied with the repro sender but...
There was not much of the silicone left!

Regards
Declan

[RobThomas]

Good point, Declan. This stuff was sold as 'ethanol friendly' hose pipe, but, I'll whip it off and have a look at it, just to be sure.

[RobThomas]

Reading the advertising blurb again it says that fluoro-something lined hose is resistant to fuel and vapours so long as it doesn't stay in permanent contact, suggesting that it is OK as a filler neck but not, as Declan said, a seal for the sender.


Some more 'reading' material...
http://www.silflex.com/products/fuel-oi ... tions.html

[BLOWNMM]

Declan
I measured my Minor gasket at 60.3 PCD so I believe the Minor and MG TD screw patterns are the same. As a matter of interest your measurement of 60.33 mm. is equal to 2.37519 inches, just 1.9 tenths of a thou over 23/8 inches. As for the fuel resistance of silicone hose I have 2 lengths of 42 mm. dia. silicone hose in my supercharger manifolds. However they are fluoro lined to resist fuel. They were not cheap but there was no alternative I was able to come up with. See link.
Bob
http://www.jsperformance.co.uk/silicone ... cone-hoses

[Declan_Burns]

Bob,
The 60.33 is what is mentioned on the Holden Website
https://www.holden.co.uk/displayproduct ... de=070.012
but it is probably originally the 2 3/8" you mentioned and they just rounded it off.
Regards
Declan

[palacebear]

I'm joining the 'fuel smell' club. Had to leave the moggie parked on a slope yesterday leaning to the nearside and with a full tank. Walked past it this afternoon and could smell petrol at some distance. Boot and interior full of fumes. Filler tube wet at the top. Another job for the ever-lengthening list!

[Budgie]

I'm joining the 'fuel smell' club. Had to leave the moggie parked on a slope yesterday leaning to the nearside and with a full tank. Walked past it this afternoon and could smell petrol at some distance. Boot and interior full of fumes. Filler tube wet at the top. Another job for the ever-lengthening list!

I'm jealous as at least you have got a head start with a visible wet area. I just have the smell but not all the time and it's there come full tank or lower .

[oliver90owner]

Anybody considered if the system is vented? If the vent is blocked, pressure will build and gases will try to escape through joints which otherwise might be adequate.

[biomed32uk]

Seems a few of us are looking to eradicate the fuel smell.

I have fitted some filler hose as recommended by Rob, it went on well and is all fine and sound. The old one was very rotten / porous and I thought that was it, did that last summer along with the sender gasket.

I did put a wipe of hylomar on the gasket, but never thought about the screws. A nylon washer under the heads or low strength Loctite round the screws should stop anything getting up there. Seems the improved gasket may be the solution and I am willing to give it a bash as it seems that it will fit.

Without taking the floor out its hard to have a sniff round the tank, have to make some tube up and inhale through that to see if the source can be found

The tank is perfect, I get the smell full or almost empty as it is now, so it's vapour coming from somewhere I reckon more than liquid fuel. Must be down to about 1/4 of a tank now, or less.

If the tank is sound there really is only two places vapour or liquid can escape from I suppose.

Usually if the vent is blocked fuel starvation will happen, especially at speed when demand is higher, that's all fine. I have an old Waso cap on the car which looks like its been part of her for years.

I shall report back after some further investigations