1998 Chevy Malibu 6 cyl Two Wheel Drive Automatic 183000 miles
The heater does not blow warm air at any temp. The thermostat is new still no heat. When the heater is turned on and driving car temp goes up to around 200 as soon as turn off or flip to a/c it cools down so that tells me thermostat is working properly. The heater hose on the front side of motor gets red hot to the touch however, the rear hose next to the firewall side stays cold. The front line was bled of air very little came out. Is there a valve that I can adjust to open it up to flow warm water thru heater core? Is the hose stopped up? Is it the heater core? Help me please it is getting cold here in the mornings now. Thanks !
That engine was prone to clogging the heater core from oil getting in the cooling system or the coolant (dex-cool) sludging up from either mixing with regular ethylene-glycol coolant or neglect.
Check the overflow tank (engine cool) for a brown or black sludge in the tank.
Secondly, make sure that you are opening the bleeder valves when you are adding coolant or air pockets will form and the heater will not work.
Finally, pull the hoses off the heater core and put a garden hose on one of the heater nipples. Turn on the hose and watch for water to come out the other nipple.
If no water comes out the other nipple after about 15 seconds it will be necessary to replace the core.