Need to replace a core plug in brother's Land Rover Discovery. It is on the back of the block, close to the bulkhead, so means engine out.
Then I've come across expanding rubber plugs, apparently used with success in the US. https://www.napaonline.com/en/p/NDP6004012

Has anyone any experience of these. Or just any thoughts.

Was denied access to the NAPA site!

I'd imagine they're similar to what is sometimes used to replace the sump oil drain plug when the threads are stripped?

If the core plug is close to the bulkhead, is there room to remove the plug and fit the expanding type?

I don't suppose there is any other way of replacing the plug with a standard one e.g. drilling a large hole in the bulkhead to access the plug from the vehicle interior. Probably might have been possible on the older Land Rovers but not the Discovery - too much stuff in the way.

Have you asked anyone familiar with the Disco e.g. L/R dealership mechanics, L/R forums? re:- how they deal with a leaking core plug in this awkward location?

Is the core plug just pin-holed or completely rotten? If it is just a pin-hole, maybe you could clean up the area and use an epoxy sealant e.g. Araldite?

(I once came across a cup-type core plug that had been filled with Isopon Body Filler to stop a leak!!).

If it's a very minor leak, maybe try something like Bar's Leaks first?

This is a long shot, because I'm not familiar with the L/R Disco. Any possibility that you could attach a metal strap across the faulty core plug with a rubber sealing ring/washer? i.e. any fasteners adjacent to the core plug that you could utilize? (I realise that space is liklely extremely limited).

AL.

Never used one.

also found this:

http://mgaguru.com/mgtech/cooling/cool_105a.htm

Similar idea.

Most radiator caps/cooling systems are 7PSI pressure relief protected so nothing massive pressure wise that would trouble these expanding core plugs.

If it were me I'd give the rubber one a try. Being rubber it is also going to seal imperfect surfaces.

Thanks for the replies so far guys.
When it leaked, we investigated, and were initially puzzled by a flat plate over where we expected to find a hollow containing a core plug. The plate was 'chemical metal' glued over the core plug hole, but had come unstuck. Once pulled out, we can feel the plug in the cavity. It feels good, but not as far in as expected. My guess is that it has been replaced, by hand, and of course will not seal, as it needs striking with a hammer. I would not be surprised to find the original still inboard of it. I dread to think what state the hole is in, so an expanding rubber one will be easier than the expanding metal one. A rubber one will also tolerate a little offset if we don't align it properly due to the tight space.

Removing the whole fascia, and then trying to guess exactly where to cut a hole in the bulkhead may actually be more difficult than removing the engine. I have a Land Rover specialist in the next street, he says engine out. Sadly, he and I are 55 miles away form the vehicle, or I'd let him do it.

At least no-one has popped up and said "no way, they've had one fail".

I've found two instances on Land Rover forums where people in the US have used them.