How to make some simple plugs to test your radiator.
We all know Moke radiators aren't the easiest thing to remove, so it's always a good idea to pressure test them before putting them back in. There's nothing worse than finding an annoying leak the minute you fill it with coolant! All you need is two 3/8 cup head bolts 1 1/2" long, two wing nuts, two 3/8 flat washers and two bits of 5/8 heater hose.
The heater hose should be about an inch long, and cut as square as possible. The easiest way is to buy a hose cutter for a few dollars in the plumbing/reticulation department at Bunnings, or use a sharp knife lubricated with WD40/CRC/soapy water. Then just assemble as shown above, and insert them in the top and bottom outlets.
A couple of turns on the wing nut until it is firm, and you're all done. If you don't want to buy some wing nuts, then plain 3/8 nuts will work just as well tightened with a spanner. Now just drop the whole radiator into a tub of water, and add a bit of pressure. Depending on your radiator, you can connect the air line to the heater return tube or the drain plug. A bit of detergent or coolant in the water makes any bubbles easier to see.
Just be sure to always use the correct neck length cap with a maximum 13psi to avoid any damage to your radiator. Don't be tempted to use a blanking cap and pressurise through the overflow tube - there will be nowhere for the pressure to escape and you will almost certainly split a tube or the tanks will blow up like a balloon!