My 92 300TE had the head gasket and valve seals (no guides) done at 90 kmiles. I bought it with 120kmiles. It has 145kmiles now. Since I've owned it it burns about a quart in 1000 miles. I was thinking about giving it a valve job in the near future but I'll stay away from that after reading this thread.
Bruno

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1992 300TE 160 kmiles