30 below and no heat!!!

[sandman104]

Hey everyone, This is my first post
I drive a 92 grand am with a 3.3l v6, My car blows only cold air and overheats in about 5 minutes!! I changed the water pump and checked the thermostat which was working fine. I held both the hoses to the heater core and neither got warm, even though the engine was over heating. I thought it could be the heater core, but wouldn't the hose going into the heater core still be hot? I dont want to rip out the heater core if thats not the problem. I also tried to bleed out any air, but my car doesnt have a bleeder valve, so i did the best I could.
Does anyone have any ideas??????????

[4kQuad]

The hoses to the heater core should be the same temp as the hoses on the raditor. if not the core is most likely clogged, not allowing water to run through it.

A quick test would be to pull the hoses at the firewall from the core, with some sort of plumbing nipple hook the two ends together. Secure the two hoses so they are not allow to fall or jump around.

Drive the car and watch the temp. If it stays fine, change out the core.

If the raditor is clear and the stat is working and the hoses are staying cold. odds are it's clogged not allowing the water to move freely.

[pokesmot]

Check the airflow from the vents... if there is minimal airflow no matter what position the fan selector switch is in, it could either be a vacuum leak or a clogged evaporator core. (or the blower motor... check to make sure you can hear it running)

If it is a flapper (vacuum leak), the top portion of the dash (just above the instrument panel) comes off without removing any screws. its held in by velcro and metal clips, so just push straight up, then you will be able to check the flapper for proper operation.

the 1993's and some other models are known to have a clogged evaporator core.

Assuming that you have minimal airflow, and it isnt a vacuum leak or cooling system problem:

so you have 2 options to try and fix it: one of them is going to be a Royal PITA, and the other is fairly simple.

Option 1:

Try the simple solution first:
on the firewall of your car, with the hood open, there is a black duct above the rack and pinion. Just below and to the left of the master cylinder there is the blower motor resistor which is a football shaped thing thats held in by 2 screws. remove that, and try and find a vacuum thats small enough to fit into the opening. If you take a flashlight and look through the opening it, you will be surprised to see your evap core completely clogged with crud :p

just keep prodding the evap core with a vacuum and try and get as much dirt and stuff off as possible: you will need a good vacuum for this, like a shop vac. something with LOTS of suction.

Option 2:
try and avoid it at all costs... its REALLY a PITA!
(I struggled to get my evap core positioned and back in for a looong time.)

If Option 1 does not work you will have to tear your center console out, remove the fan box cover, remoe the heater core, then remove another panel, then you can either discharge your AC and take out the evap core to clean it which is very difficult and will probably result in a valve in the evap core needing to be replaced, so just remove the bracket that hold the evap core lines, and pull the evap core out a few inches to allow you to get in there with compressed air / vacuum.

[antoniobanderas]

since you say both hoses going to heater core are kind of cold ,but engine hot,it points to a clogged engine gallery water cooling internal duct,i would disconnect both hoses from firewall,and try blowing air from one and let see what cames on the other,then,plug one and blow compressed air on the other hose and reverse same thing on the other,,i bet you you get rid of the stoppage,,maybe someone used at one point radiator powder to stop a radiator leak ,problem is ,it works so good ,it also plugs more than it should have ,thats why is not the best solution ,it creates more troubles in other parts as you can see by now,i feel this is your fix as it was on mine 1993 grand am

[cocobob]

Yeah but he says that the engine overheats while no heat comes out of blower vents. Sounds to me like the water pump is not circulating the antifreeze thus not pumping glycol into heat core and not pulling out overheated glycol from the block back into radiator for cooling. If this is the case thank god its winter & because of the cold the engine hasn`t had a meltdown.

[sandman104]

Thanks guys for your help. Turns out it was a bad airlock. There is no bleeder valve on a 92, so it was a real pain to bleed. Was about to give up and the line burped!!

[antoniobanderas]

it will prob get better but still will be slow to warm up due to the before mentioned let us know

[mrjoecanadian]

Originally posted by sandman104
Thanks guys for your help. Turns out it was a bad airlock. There is no bleeder valve on a 92, so it was a real pain to bleed. Was about to give up and the line burped!!

I was just about to say it's an airlock, just cause a fellow worker has the same problem in a van right now.

Good to hear it's fixed

[tenspeed]

It's getting cold and lots of people have heat problems. Here's some basics.

If the heater hoses are not hot, there's no coolent flowing. There's only a couple of things in the circuit. One is a valve that controls how hot it gets and two is the core.

Evap cores, vacuum flappers and poor air flow don't mean squat if the lines are cold. Cores don't usually clog unless you poured some clogging crap into the system. Cores do, however, leak. That's when the windows fog and the air smell sweet. That sweet smell lasts till you find out how much it costs to replace that sucker.