I recently took the entire dash and heater apart, for the second time. I replaced all the old cardboard vent tubes with new plastic, but replaced all vacuum lines the first time around. Heater worked great after that. But this time, the air gets just a bit warm, but not hot, when I turn on the heater. I have a 180 thermostat, and the air is currently 65, engine runs right at 180-190. I put about 25 miles on the car today, some on freeway, just to get it warmed up. It appears that the flap that diverts the heat is moving. Is it maybe not getting hot enough? Anyone ever had this happen. Of course, I would rather that it not get hot enough, than too hot!
you can check a couple of things, low coolant, an air bubble in your cooling system that is trapped and not allowing enough coolant in your motor,a bad thermostat-even if it is new it could be bad! check and make sure that your heater hoses are on the proper connection, finally make sure your water pump is not leaking and pukeing coolant on the ground or blowing under pressure.
Replace the thermonsate I had the same problem. Now it works great. You may want to replace or boil out the heater core. If its orginal it needs a good cleaning.
Great suggestions, but... Radiator was removed, recored (cut off the top, ran a cleaning rod down all cores and cleaned out any large chunks, top welded back on and painted), etc last summer, less than 200 miles ago. Heater core was replaced at same time, as well as all hoses, thermostat (190 degree). Also, new water pump. Coolant was of course replaced, and soon afterwards, I swapped out the thermo for 180, since Texas summers are really hot. The heater worked VERY well until I took apart blower unit, thinking it had blown (later found a wiring issue was not letting the blower run). After removing and replacing the blower and wiring, that is when I lost my heat. No changes to cooling system, so no swapped hose connections. I have not had heat for the entire winter, due to no blower, until the last month or so. What about that bubble? what might cause it, how do I fix it, etc. The coolant is about one inch below the top of the radiator, it could use a top-off, but should be well within safe range, shouldn't it? Engine continues to run right at 180-190, exept when stopped in summer heat, it may rise to 200 at long stop lights or when parked idling. I would guess that the thermostat is fine if it is running right where it should be. Please, more suggestions unless I have missed something in these responses.
It's a DC motor did you wire it up right? It just maybe running backwards! It's a easy thing to check. Let us know !
hhmmmm...... does the blower force air out of the vents? maybe wires backwards on blower motor? check heater hose going into and out of core for circulation ..... i.e. hot after being driven (or pull it off while engine running if you are really brave ) maybe something is in front of the heater core in the air box not allowing air to pass through ..... (piece of plastic or something) the diverter flap thingy .. dunno nuthin' bout ... but maybe not working correctly (if it is vacumm operated, use a vacumm pump to check operations and also vacumm amount) Hey, you asked for suggestions, just mine Robert good luck ps ..... I'm in Texas also, and I just bypassed my heater core on the vette and don't miss it a bit, even in the "winter"
Heater blows good, just cold. Thanks for further suggestions. The flap...may have to make sure it is connected on the front end. I can see the temp controller moving back and forth, since it is on the inside in plain sight, maybe I knocked the other end loose and it is only giving me half-flappage? I will check that. Thanks for the suggestions.
the bubble is when air gets trapped in the cooling system somewhere in the engine when you refill from a repair or a drain and fill. there are some tools available to purge the air from the cooling system or you can remove the radiator cap and with the fluid a little low, start and run you engine,turn on your heater,full hot temp and fan on high-this helps circulate the fluid in the system,watch your temp gauge so as not to over heat it,as it runs it might "burp" some fluid from the radiator and help to get the air out of the system,after all of this as your fluid level seems to settle down then slowly fill the radiator to the proper level-if all this fails bring me the car and I'll find your problem. wayne
hey waynesfords, I've heard about the "bubble" situation, but never had it happen to me ..... If this is the case, would the coolant be circulating at all ? scooper, did you check the heater hoses at the core to see if they were hot after running? Robert
I don't see anyone saying to check the heater valve on the heater hose if it has one. That hose should be connected to the manifold, check for heat in the hose to the valve and beyond. Also the vaccum switch that controls the water valve.
I had this same thing happen to me once, after I had the heater box apart to change the heater core. I had checked all the logical things (listed above) but it turned out that when I re-installed the heater box, I kinked the hoses up against the firewall. Kinked hoses = no hot water to the heater core = no heat. Hope this helps. Sam
Great idea guys. I will take off the cap, run it to hot, and see if the hoses are hot. "Two birds with one stone" and hopefully solve my problem. I will write back if this fixes me. Also, will check for kinks, etc.
