In my previous company, we had a spate of MGB Oil Cooler Leaks through cracked pipe/welds (in fact I discovered one on deck, and we used some very creative interpretation of the FTL scheme to eventually fly home after the repair!) Another crew had one at about FL80, I recall, and when they got to the nearest deck (Clyde?) things had got pretty hot and interesting.
The company test pilot (MB) used to produce an excellent fleet newsletter, and in one issue he described Aerospatiale test data for the MGB on a test rig. I forget the precise details, but it described how, with the rig running, the 'plug' was pulled out of the base and the clock started. Within a very short time white smoke was coming out of the mast bearings and not long after that the whole thing seized. It was of the order of 11 minutes I think. certainly it was sobering.
I'm sure HC can provide more detail and explain how the 225 alleviates these problems.