I agree completely with the last post, my guess on reading your statement that there is cold pressure was a bad head gasket or a cracked head. Since cracked heads are rare on the M104, I'm betting the gasket has failed, either for the reasons listed above or by the use of a defective gasket (some aftermarket ones are problematic).

Overheating under load with cold pressure is a sure sign of exhaust in the coolant.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!