Fuel leak from tank??

[Lotus Boy]

Can someone guide me as to the problem I have with escaping fuel please?

 

I noticed faint whiffs of petrol recently, only when parked up in garage and smelling the boot and wheel arch area. I then spotted a wet area on the chassis rail underneath the point the leading edge of the RHS bar on which the tank sits, joins to the chassis.

 

At first I thought the fuel pump gasket had perished and indeed it does look a little shiny and wet but when I looked down the front of the tank it looks like there is a damp/moisture line about a 1/4 way up from bottom and this patch is the full length of the tank. Has anyone else seen this? See pic below.

 

Picture - looking down from above the tank. The front face of the tank - hopefully you can see the damp area at the bottom of the tank.

http://farm3.staticflickr.com/2859/9319993508_8ccebf0946_b.jpg

Fuel tank front by snapper seven, on Flickr

 

Picture - looking up from under the car. I wonder if some of the padding has come away from the bar causing the tank to rub against metal? Any thoughts?

http://farm8.staticflickr.com/7371/9320019928_0a09371997_b.jpg

Fuel pump gasket by snapper seven, on Flickr

I guess I am looking at taking the tank out and inspecting though probably won't be able to do this until after the Silverstone event.

 

To add, the car is a '94 HPC Injection model. The pipes look ok with no cracking when squeezed and the fuel sender gasket looks ok too, there is no evidence of fuel on top of the tank.

 

I'll probably have some tank removal questions in a little while too if I can't find them through searching.

 

Anyway, any thoughts advice would be welcome.

 

Cheers

David

 

Edited by - lotus boy on 19 Jul 2013 13:37:30

[Rampmonkey]

Evening!

 

I had a similar issue last year. Got the frequent whiff of fuel in the garage and found evidence of a leak on and under the tank. Removal and inspection highlighted a hairline crack caused by a stone chip of all things. Really tricky spot as the fuel was weeping through capillary action through a crack I couldn't even see!

 

Whip the tank out, vent it overnight to rid any vapour. Depending on what you find, you can either liquid metal repair it (yup, sime as that!) or get a weld fix for anything more substantial. After that, I painted with loads of layers of stone chip resistant paint. The underside and leading face also have speed tape for an extra precaution!

 

Hope this helps.

[Stationary M25 Traveller]

Didn't think much of the original foam rubber strip under the tank. Replaced all mine with 4-5mm thick nitrile-bonded cork gasket strip.

[rgrigsby]

I don't think it will be this but the gasket on my fuel level sender perished and was causing a leak recently, only when on a full tank but it made quite a mess!

[Lotus Boy]

Thanks for the replies.

 

Sounds like the tank needs to come out for inspection then Rampmonkey. Is it ok to remove with small amounts of fuel in (to then drain completely once outside the car)?

 

SM25T - that sounds like a sensible upgrade. I'll do that. I'm guessing it is easy to get hold of those strips?

 

rgrigsby - the top of the tank is bone dry with no witness/stain marks - has to be either a pin bole or the pump gasket I reckon. Shame as that would've been a much easier fix!

 

Cheers

David

[Stationary M25 Traveller]

Yes ... if you find a gasket manufacturer. I got a square piece and cut it into strips with a Stanley knife. Try British Gaskets in Sudbury ?

[Jason Plato]

I cut and used strips of rally car mudflap material on all the contact surfaces and bonded it to each face with a little silicon sealant to stop the stones getting behind it. - its on ebay for about £15 for a load of it or smaller quantities for much less.

 

 

[the green sneaker]

before you take the tank out have you checked the rubber hose that connects the tank to the filler cap ?

its about 5 inchs long mine had perished and I had to replace it which solved my problem

[mark not max]

I had the same problem as green sneaker on a 96 HPC a few years ago. Mine highlighted itself when refuelling, leaving a pool of fuel on the forecourt.