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got a tank of nitrogen out and put the hose into the drain plug


That's called backpurging- when the back side of a weld gets to a certain temperature, it'll react with oxygen in the air. And the oil inside, which will burn.

So the nitrogen protects the back side, just as the co2/nitrogen/argon mix does the front...

pretty cool.

t

'89 V6 4dr- '4- Doris'