Great find. If I knew about these before I bought the rovahfarm plugs, I would have bought them.

 

STOP SCEWING AROUND with those plastic as well those brass replacement plugs without the O-ring pocket preventing the O-ring from being spit out.
Get a early Range Rover brass plug with the O-ring pocket and be done with vs playing chicken with an overheated engine stuck in the middle of nowhere.

I saw this once out motorcycle riding back in the bush and ran across an early 94 Disco, the burp plug top had broken off.
With a knife blade I unscrewed the threaded section then whittled a tapered plug fron a green tree branch.
Topped off the radiator with river water then screwed in the tapered plug good and tight. Hell no leak even with
the cooling system pressureized after idling app ten minutes. Disco owner had zero mechanical abilities, totally clueless about his Disco.

I hopped back on my dirt bike again exploring doing my thing after telling the Disco owner to purchase a used older brass Range Rover plug and O-ring.

What LR idiot engineer came up installing a plastic burp plug needs to be fired vs the brass plug.
Trusting you Disco out in the bush with cheap plastic parts is insane.
A Disco One 5-speed owner since new knowing every weak point and part before being assembled into a complete Disco One. Steering boxes, both ends diff's rebuilding,
5-speed transmission, transfer case.
OB1 for a reason also 99% being a 5-speed vs owning a slow automatic aka "turd"........~~=o&o>......