Filler neck leak

Could someone confirm what should be under this a metal or paper gasket. Got an annoying leak which is proving difficult to sort out
Can't see any pinholes in it

 

From memory, a large fibre gasket. They do pinhole at the bottom. Try shining a torch in.

 

Also getting the nut inside tight enough can be a game.

 

Someone does a better nut now with a hex socket, The original stupid thing slips no matter what you do !!

https://www.ebay.co.uk/itm/153638564517

 

Or you csn get a better tool to tighten it...made by Empi IIRC.

 

Or some flat bar welded to a socket

 

Not really. The Empi tool doesn't use the hopeless shallow slot in the nut.

 

The cheap "big screwdriver" tool is OK if you can get a straight hard lean on the tool with the engine out.
But it jumps out very easily if you do it with the engine in place and you angle the tool.
The EMPI tool grips the inside of the nut.

 

9 times out of ten the slot is knackered. If the nut has been fitted with the Empi tool nothing else will loosen it.

Empi are like a warehouse filled with stuff from wherever they can get it. Some good, some bad.