No pressure

[jlagnese at massed.net (John S. Lagnese)]

Hi,
    My 87 16V Scirocco isn't building up any pressure in the radiator. The temperature goes up past the led, but no ressure. It also has just a trickle going into the reservoir tank. The water pump must be working, I have plenty of heat.
    It has just had a new water pump installed. The thermostat has also been replaced. The radiator has also been flushed. 
    The water pump died last September, it was leaking like a sieve. It sat all winter with no coolant.
    Any ideas? I have had it out at a local garage because I really haven't got the time during the school year.
Thanks,
John