hi, i was searching for "no heat" posts and found diagram for heating system. i just assumed my heater core was not working. the vents blow all levels, just not hot air. should/how to check other items like control valve,etc. or would it be leaking antifreeze? 85 gt/auto thanks.
[This message has been edited by maybenot (edited 08-14-2013).]
The temp lever on the HVAC control is attached to a cable that moves the blend door in the HVAC housing. If the lever moves freely (it should have some resistance), the cable may not be attached at one end.
i feel some resistance, not freeplay at all. and i hear something when sliding it. with no leaks, i was just wondering are there other things to check. i thought if a core was bad, it leaked, otherwise it had hot water flowing through it and the blower motor just blew that heat into vents.
The heater core may be plugged. No water flow = no heat. The heater core is fed from the large nipple on the thermostat neck and returns to the water pump housing via the 5/8" hose attached to the pipe (about the 10 o'clock position when viewed from the face of the engine. The coolant is routed to and from the heater core via under car tubing the runs along the passeenger side of the fuel tank. Check for damage on the undercar piping. Do you have a thermostat in the car?
Is this car new to you? Has the heater worked for you in the past?
My third Fiero didn't have heat. What I found was the previous owner bypassed the heater core because it leaked. He used rubber hose to connect the in and out lines under the car, directly below the heater core area. I changed the heater core then removed the bypass hose and reconnected the hoses as they should be.
Make sure the coolant system is filled correctly. If you have an air pocket, you will get no water flow. This means no heat, as well as overheating the engine. The temp gauge can also read incorrectly if there is no water flow. Small chance this is the problem if you drive it often, but if its parked and you are working on it, its worth noting.
hi guys, yes the car is new to me and the heat never worked since i have had it. i have checked the lines running under the car and they are perfectly round not crushed/pinched, or nicked. the hoses are not bypassed and i have a new thermostat as well as all new caps. i was having overheating issues when i first got it, and thanks to the forum, replaced those as well as all sensors and properly filled/burped system. it has run perfect ever since. except no heat. how do you check for clogged heater core? if it was clogged, wouldnt that effect something downstream? i am not adverse to replacing the heater core, its relatively inexpensive. its just like i said in the beginning, i didnt know if the heater control valve or vacuum hoses could be bad or checked first. no sense replacing what isnt broke.
The only thing that can be "wrong" with the heater core is that it leaks or the fins that allow air to flow through it are clogged up with dirt, hair, leaves and junk. If it ain't leaking, at most all it needs is to be cleaned. Before going through all that, detatch the two hoses and try to force water through it with a water hose. If you have good flow, the worst thing it could be is dirty on the outside.
It is also possible to have a clogged hose where it attaches to the engine block. I've seen pics of that situation here also. So don't buy new parts yet.
Also, just to be 100% clear, the heater hose goes down the MIDDLE of the car. We are NOT talking about the metal tubes that go down the SIDES of the car.
ok thats good to hear about the core. i will check the flow disconnected this weekend and then check the underside. i thought it was the pipes under doors. i didnt know there was one down the middle. excellent catch on my misunderstanding.
olejoedad, i meant no disrespect. i stated that i completely misunderstood. actually i just read too fast as i thought i knew what you were going to say about the coolant lines running under the car to front. i even read the part about passenger side of fuel tank but took it to mean that sides coolant line. my apologies too you and thank you for the original help. some people(me) just need to slow down and accept the help they are given. thank you again
