hi ya
have you got the water pressure valvus fitted they go on the water pipe that comes from the engin to the bulk head which close if the water gets to hot or to much pressure in the system it was a factory recall to have all cars fitted with them my 89 16v heater done the same and after taking the pipes off i found one was jamed shut so the water was not getting in to the heater as it should ,worth a look. got 2 new ones and now the heater is working good
can i add that i had a mk2 89 gl which never had them and one day i was going to work and just came out a 40 mph in to a 60 mph (putting my foot down) and bang the car filled up with steam burnt my leg and i wrote the car off jumped out thought it was on fire but found out the water pipe was bloked and the pressure got so much it blow the matrix so if any one has taken them out make sure your car dose not block up or u will be in the same trobble i was in and its not good

beter safe than sorry
