No, you don't need to remove a heater hose to bleed the coolant system. Here is Benzmac's opinion of how to get the air out:
Benzmac wrote on 05-20-1999:
Yes the drain plug on the block is located under the exhaust pipes on the under side of the block. Be sure the installing new coolant be sure to try to overfill the reservoir this is the only way to purge the coolant system. After the system is completely full, turn on the defrost and crank the engine. If you don't get heat out the top soon, turn the engine off and add more coolant.(Until it pours out the top of the reservoir)
Or you can search "Replacing coolant for 94' C280" for the entire thread.
PS: Thanks for letting me know the shop in Huntington Beach. I did get a check engine light last week. (See "94 C280 cold start problems..." for detail) What a coincident. I haven't have it checked yet but at least I have the peace in mind of knowing where I can go to. Thanks.
Harry (94 C280)