hotmine Posted December 20, 2004 Report Share Posted December 20, 2004 I have some (or lack of) heating issues to inquire about from the brightest on this board. I have checked the archives and they were not too helpful. I was confused. I am hoping for a concise reply, if possible. About 2 - 3 months ago, the car started running hot, so I changed the thermostat, and things went fine ever since until now. Lately temperatures have been dipping below 30 and that is when I am having problems of no heat or little heat sometimes. Also, there is some warm air on the passenger side and cold air on the driver’s side . When the temperature goes into the upper 30's and higher, the heat seems to be fine (acceptable), but not below 30. Could the thermostat be the problem (although I changed it 3 months ago). And if it is not the thermostat, could it be the heater core ( doubtful). Plus, why the cold air on the driver’s side and some what warm air on the passenger side. Your input is appreciated. Thanks Link to comment Share on other sites More sharing options...
cadillacjeff7777 Posted December 20, 2004 Report Share Posted December 20, 2004 Take it out for a drive and then check the temp on the DIC. Should be around 200°F I had a 93 Seville that had bad heat when it would get down there and would get poor milage during the winter and it was the thermostat. 2008 DTS Link to comment Share on other sites More sharing options...
Scotty Posted December 20, 2004 Report Share Posted December 20, 2004 check the coolant level, a low coolant level will give you poor heat Link to comment Share on other sites More sharing options...
stsjoe Posted December 20, 2004 Report Share Posted December 20, 2004 and make sure there isn't a BIG hole in the hvac box! No i'm not kidding Joe Link to comment Share on other sites More sharing options...
hotmine Posted December 20, 2004 Author Report Share Posted December 20, 2004 coolant level is good..thermostat, I will check . but where is the HVAC box on a 1995 caddy deville..also no temp. gauge on car.. Link to comment Share on other sites More sharing options...
Scotty Posted December 20, 2004 Report Share Posted December 20, 2004 coolant level is good..thermostat, I will check . but where is the HVAC box on a 1995 caddy deville..also no temp. gauge on car.. I just went to the owners manual for your car and and was surprised to see that you dont have a digital temp guage or even an analog guage you only get a message from the DIC... Feel the hoses going in and out of the heater core they should both be warm, unless there is a restriction in the core, you might try to take the hoses off and flush out your core in both directions.... Link to comment Share on other sites More sharing options...
adallak Posted December 20, 2004 Report Share Posted December 20, 2004 Did you set it at 90 degrees to open the airmix door completely? This way you'll get maximum heat even if your heater core is partially plugged (could be since it is ten-years-old car). The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
hotmine Posted December 20, 2004 Author Report Share Posted December 20, 2004 I did set it at 90 ..slight improvement..but still getting cold air on dirver's side and warm air on passenger side..i tend to think it would not be the heater core since I don't have probelms when outside temp. is high 30's/40 or above...I am inclined to think it may be a bad thermostat..what do you think.. Link to comment Share on other sites More sharing options...
Scotty Posted December 20, 2004 Report Share Posted December 20, 2004 Did you install an OEM thermostat? The thermostat on the NS is very long. I kind of doubt whether its the thermostat however. Did you feel the heater hoses? The fact that you get good heat at high 30s has no bearing on the kind of heat you get below 30. Its possible that you have reached your cores ability to warm the cold air below a certain temp with poor coolant flow through it. It sounds like you heater core is not getting hot enough. Are you getting the same volume of air from the driver and pass outlets, its just that the driver side is cooler than the pass side? Have you tried pulling codes to see if you are getting an HVAC problem? Link to comment Share on other sites More sharing options...
Northstar Posted December 21, 2004 Report Share Posted December 21, 2004 Sounds like your air mix door is not working. Thats why you have two different temps on each side. Pull your glove box out and view it to see if its operating properly. Link to comment Share on other sites More sharing options...
seattle_fleetwood Posted December 21, 2004 Report Share Posted December 21, 2004 It seems like this problem isn't exclusive to MY '91...lukewarm on the passenger side and cold on the driver's side. I too replaced my thermostat and it didn't help at all, made sure the coolant level was good, which it was, so I posted my question and this was the repy I got: "Mixer Actuator" That's it ? [mixer actuator]...So I checked out my factory service manual, and it appears there are some vacuum diaphragms behind-ish the glovebox that have to do with mixing and actuating and controlling the directional 'doors' in the ductwork...Does this sound reasonable to anyone...anyone? Link to comment Share on other sites More sharing options...
hotmine Posted December 21, 2004 Author Report Share Posted December 21, 2004 air volume on the diver's side is in fact greater than it is on the passenger side ..I have not felt the hoses (still at work) and will do so as soon as practically possible...I will also, as suggested, remove the glove compartment to see what is going on behind there..thanks for all suggestions Link to comment Share on other sites More sharing options...
Ranger Posted December 21, 2004 Report Share Posted December 21, 2004 Disconnect the heater hoses at the firewall. Clamp on old garden hose with the male end cut off on one fitting and flush the heater core. Then put it on the other fitting and flush it in the other direction. Sounds like your heater core has sediment (maybe sealnt tabs) settled in the bottom half. Link to comment Share on other sites More sharing options...
hotmine Posted December 21, 2004 Author Report Share Posted December 21, 2004 as soon as weather conditions allow, I will flush the heater core..check the mixer actuator and report back ...thanks for all of your help Link to comment Share on other sites More sharing options...
Northstar Posted December 21, 2004 Report Share Posted December 21, 2004 "Mixer Actuator" That's it ? [mixer actuator]...So I checked out my factory service manual, and it appears there are some vacuum diaphragms behind-ish the glovebox that have to do with mixing and actuating and controlling the directional 'doors' in the ductwork...Does this sound reasonable to anyone...anyone? Yes, Thats it. I just replaced one because of hot on one side and cold on the other. Of course it cured my problem, heat is 100% HOTTER too!!! Link to comment Share on other sites More sharing options...
hotmine Posted December 22, 2004 Author Report Share Posted December 22, 2004 I decided to do a quick test to see if I can narrow down the problem since the outside temp today was in the low 40's. Started the car up..I was getting decent heat. overall the car inside was warm. However, the hot/warm air was coming from mainly the defrost vents on mostly the passenger side...still the air on the diver's side was coming from the bottom (feet) vents and it was cold..the other side was Luke warm...I popped the hood open and felt the hose going into the core..it was real hot..the hose coming out of the heater core was warm (not nearly as hot as the one going in..is that normal)....does that narrow it down at all... Plus while there, I was looking at the best way to disconnect the heater hoses (in/out) at the fire wall to flush the core. The hose coming out (top) seems somewhat easy to remove..However the one going into the core (bottom one) looked a little harder to disconnect and reconnect...there is simply is not much room to maneuver..do I need to remove anything out of the way to make this a simple task..or that is it .. I have to try and squeeze my hand in there to remove/put it back in??...any suggestions..thanks again Link to comment Share on other sites More sharing options...
droger03 Posted December 22, 2004 Report Share Posted December 22, 2004 I had the same problem with a 94 deville that I once had. It is the heater core. I cannot tell you how many of these I have done for friends. THe problem is that sediment clogs the core (coolant supplement). Every time I do one, if you remove the core and put a clean peice of hole on it and try to blow through it, there is a considerable difference between the old one and new one. The problem with trying to flush the old one is that the sediment that's in there is 8-10 years old and has had time to harden. You can get heater cores for $37 from autozone and it only takes about an hour to do! Link to comment Share on other sites More sharing options...
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