can you post a picture of the shavings you are seeing?

if its not a stop leak product, then some metal is grinding somewhere and needs to be addressed. the only thing i could think of would be the pump ....

flush the system out with a garden hose, put in new coolant or water (on a temporary bases) and see if what comes out....

the small hose could have blown due to age...the rubber weakens with time, and with the pressure, the weakest link goes first.....

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1993 300E, 2.8 M104 .....