I am trying to warm up an old 5/16 ths nylon fuel line in place on a Ram pickup.

It is a tight place.

I have about 5 inches of the line sticking up in the clear from the crevice between frame rail and plastic fuel tank.

The instructions call for dipping the line in boiling water before inserting the steel barb. This works fine for the new line that can be held in a down direction out in the open.

For warming the old line fixed in place pointing upward
I have tried submerging a 7/16 ths deepwell socket in the boiling water,
then slipping the hot socket over the outside diameter of old nylon line stub.

I hav also tried submerging a tapered center punch in boiling water,
then inserting the hot punch into the inside diameter of the old nylon stub.

There are gasoline vapors around and I am afraid of using a flame, and wary of using electrical devices.

Any ideas on how to
heat the old nylon fuel line stub
in the tight confines beneath the cargo box
to around 212 degrees safely?