I just finished replacing the water pump, belt, and hoses (all of them) on my 1988 mb 300e. It started up just fine and there seems to be no massiveleaks anywhere, however coolant is not making it to the heater core. The circulating pump is not working and I have not yet checked to determine if the water solenoid valve is operating. Any helpful hints/clever ways of troubleshooting these two items would be greatly appreciated. Thanks, Roy in Louisiana.