Installing a HCI on an NL Fairlane with 11R heads and a Trickflow R manifold. Hit a snag putting the heater pipe on. Tightened the nut that goes into the manifold near the thermostat housing and the bit of heater pipe that goes into the nut was loose. Can't figure out what holds the pipe into the nut. There is an O-ring but nothing else. Don't remember anything being on the pipe when it was removed from the factory manifold. There must be some sort of circlip or something here surely? Anyone know?

Here's the pipe that goes into the nut.

{DESCRIPTION}

Here's the nut that goes into the manifold.

{DESCRIPTION}

The pipe goes into the top of the nut and in theory the nut bolts down into the manifold and holds the pipe. But mine is not holding the pipe, the nut is tightened down but the pipe is loose inside it and can be pulled straight back out.

im pretty sure there is 2 o rings and a c clip at bottom holding the pipe into the nut

Thanks.

Ive never, ever seen that nut off the pipe!.

And that was the problem. No one else had either. The o rings and circlip either corroded away or fell off during removal, but we managed to modify a circlip to fit and fitted 2 new o rings, so hopefully it will be ok and won't leak. It fitted up ok.