Really Cold!! No Heat!!!

i have a 90 c150 350 tbi chevy. wellll my heater doesnt work. it blows out air but it never gets hot. its always cold air, its also cold coming out of the defroster. it really sucks bc its 30 degrees here now and im freezing. i do not know why it blow out cold air only, i have a new thermostat and my coolant is right where it needs to be. can someone tell me why?

I feel your pain. its cold here in omaha too. I used to have a 92 ford f150(the reason I drive a chevy now) that had the same problem. When you would turn the temp control to hot the gate that seperates where the cold air and hot air mix wasn't closing so it always blew cold air. and go figure it was winter. on that truck this gate was behind the glove box and a little rod was disconnected. you might want to look into that, something could be blocing it or diconnected somewhere.

Also your heater core could be clogged up...try running some water thru it with some pressure...see if it flows (not to mention see what kinda gunk comes out)

Did it work at one time? Did the previuos owner bypass the heater core? This should be fairly easy to troubleshoot. The clogg theory from MadMax sounds logical (but then again im not Spock,so how the hell would I know whats logical)

thanks for the quick replies i know wut ill be doing after school, hopefully not being cold nemore

I just had the exact same problem with my 90 chev 1/2 ton.A fellow at this site helped me.with the truck running and warmed up,reach down and feel the heater hoses going to the core at the firewall.If one feels hot and the other feels a lot less hot then you have a plugged core.I took mine to the car was,unhooked the hoses and shot preasure back and forth through the core.Man a lot of black gunk came out.Now im cookin myself outta the cab and i live in saskatchewan where it gets 30 below.Also my metal pipe that comes out of my intake manifold and turns into rubber heater core hose was swelled almost shut.It is a reducer valve that is a nipple type thing that exits the back of your intake manifold.it has a rubber washer that can get hot over time and swell shut.it acts as a reducer to slow the flow of water and pressure to the heater core.good luck and stay warm my friend!!!!!!!!!!!

ok well i started my engine let it get pretty warm and both hoses were not hot but a little warm but nothing major. but now where exactly are these gates? its a pain in the ass to get to the heater core bc of that cover and now i want to know where these gates are?

well i no longer need to know nething about why me heat dont work. everything is fine except i have a cracked head YAYYY!!!!! i didnt know that when ur antifreeze turns this brownish color that it means it getting alot of air and i have seen alot of air bubble in it, well its coming from the exhaust, how more lucky can i be?