This is an update to my earlier thread, but with a new thread title.

As stated in the earlier thread, my 1991 420SEL (W126) car developed a sudden, but fairly rapid/large coolant leak, from a strange place under the engine.

I got underneath, and discovered that there is a pencil-eraser-sized hole in the engine block, that coolant streams out of. I guess this is a case of corrosion, as the block is aluminum. Although the actual leaking started suddenly...

I'm looking for any and all ideas as to ways to plug/fix the hole, short of replacing the engine block.....

Given that this is exposed to coolant, the "plug" would need to survive exposure to coolant, and temperatures in the 200F range, I suppose. As well as be strong enough to resist the pressure from the pressurized cooling system.

The hole is not really round. It's basically a quarter inch by a third of an inch, and somewhat irregular shape. It's kind of in a crevice/corner, fairly low down on the rear of the block, near the bell-housing.

It's somewhat accessible from underneath, depending on what the repair procedure would be.

Do shops do things like braise or solder metal in this kind of situation? Is it like radiator repair (albeit aluminum)?

Other thoughts that have crossed my mind (not necessarily GOOD ideas, though!) are:

- some sort of "liquid metal" product, gooped in the hole area and let dry/cure. Or perhaps something like Permatex's radiator patch kits...

- a rubber plug of some kind. It would have to be "squishy" enough to fit into an irregular hole, although perhaps I could drill out the hole area to be more round. I even thought of the basic concept of a tire patch kit - with the rubbeerized patch soaked in some form of glue, then poked though the hole, and partly pulled out again. But I don't know if 1) it would hold, or 2) would it survice exposure to hot coolant.

- if I drill out the hold to be more round, perhaps I could screw a metal screw into the hole, to be the plug.

The car is probably only worth $2000 or so, but it seems a shame to have to part it out, or scrap it, just for this....