i have a lg4 87 firebird. this summer i had to replace the intake manifold and later i removed the ac compressor. could either of those affected the heater core? it wont blow hot air now unless the rpms get past 3k or so

 

Did you put a thermostat back in when you put the water neck back on the front of the motor?

When your driving, what temp does the car get up to after the manifold swap? It's a common thing to miss when putting it all back together. Without the thermostat, the car won't get warm enough to run the heater generally unless your sitting for a long time or running the motor hard.

 

it does have a thermostat. had a couple in there to make sure that wasnt the problem. manifold temp is 205-210

 

ive also removed the smog pump and egr stuff. do any of these or the ac compressor supply vacuum to the heater core?

 

With the car fully hot and the heat all the way up..grab the two heater core hoses that go to ur heater core..if one is hot and the other cold..then ur heater core is clogged..

Checkout my videos below on how to replace a heater core..and please subscribe for free to my youtune channel..thanks

 

thanks that appears to be the problem

 

nice vids btw im gonna give it a shot in the next few days