Sounds like the dreaded head leak to me. O-ring that seals the combustion chamber from the coolant passage has failed. I've got the same situation. Thinking of an engine swap in the future. Any other ideas from the list?

I pulled over and there was coolant dripping from
what appeared to be the overflow tank. There was definitely a spray pattern
coming from the tank. The overflow tank was full and the expansion tank was low.

Leo Lipert

San Juan Capistrano, CA

'84 Wolfsburg Westy with Leaky Heads "La Villa Strangiata"

'00 Golf GLS