All I ever do is take the heater hoses off at the water pump and run water through it with the garden hose in both directions. I did it to my car last week and it brought all my heat back.
PDRA TOP SPORTSMAN WORLD CHAMPION -2002 Firebird Top Sportsman - 4.12 at 176mph 1/8 mile. 765ci on 3 stages of nitrous. 2000 Trans Am WS6 - in the works. -1997 Trans Am WS6 M6- 10.80s N/A, 3,650lbs, 500+ mile road trips. Sold 3/2011.
The way I did it today was take the hoses off the firewall. It's a good idea to have some spare heater hose laying around so you can re-direct coolant.
Fergymotos way eliminates the need for re-direct hoses.
I took my lines off at the firewall (to the right of your a/c hookups)
One is bigger then the other but basically you take both hoses off, put your extra hose on the opposite connection your going to blow through. Then take your garden hose and put it directly onto the open connection and flush! You should see dirty coolant and possibly some gunk come out.
Now in my situation I was lucky enough to have two extra hoses so I put the garden hose nozzle into an additional hose which eliminated any and all coolant/water getting onto the motor or wiring.
This brought the heat back immediately. It's just a band aid though, if your core got gunked up then that **** is still circulating in your coolant system. Its a good idea to have it flushed whenever you have to 70-100 bucks laying around but this will work short-term and is an easy free fix.
when my heat doesnt work i sure as hell wont be flushing my system!!! haha...im puttin a new damn heater core in because my luck in the middle of the winter the thing will go out on me on one of those cold *** indiana days where its like 10 degrees and im 4 hours from home...haha....good luck though guys!!
__________________ 87 IROC Z vert- I'ts a surprise! Just a little concoction I'm putting together, but a big project! >_<
To the kid who replaces his heater core instead of flushing it. Hopefully you are flushing the system when you're replacing the core otherwise you're going to gunk your new one right back up.
I don't have my digital camera at my apartment. If you take a picture of your engine compartment focusing on your air conditioning hookups towards the firewall I can use photo editing software to show you right where it's all at.