Cmdpapichulo

i have been having this issue since i got it 85 gsl...the heat blows very cool barely hot and only comes out warm on heat and the defrost setting every other setting it blows cold even the side vent blow cold when the the main blows warm so i just keep them shut so being in a very snowy area it sucks because it takes like 5 year to defrost the window lol i search furoms but couldnt find anything any help would be great....oh and one more thing my car got slightly hit in the front on new years it cracked the bumper and chip some paint but now my battery dies when sitting for like 4+ hours wtf is that about .....

Cmdpapichulo

20+ views and no reply or any kinda help come one people

mjm4jc

Look at your temp gauge and see if it moves from C to where it should be in a reasonable amount of time. If that's working ok, feel the heater core hoses and make sure that both are hot after running for a while. If only one is hot, there is a block probably in the heater core. Start with the simple----thermostat, proper coolant level in both radiator and reservoir, proper mixture of coolant and water, good working radiator cap, etc.

1979mazdarx7

I haven't had this problem with my 7 but sitting next to the 7 is a 1991 ford ranger. the heat never really worked since I got it back in 04. the thermostat was replaced twice. and then the radiator. past that it was the heater core itself was replaced and the heat worked and blew hot and strong. until the head gaskets went and when I finished that the heat didn't work again, the problem was the hoses were back word. It is possible that the coolant would leak from the hose if they are backward.

so checklist:
thermostat.
heater core.
correct hoses.

p.s. if the hoses themselves are blocked just get new ones.

3rd and final 7

iTrader: (9)

its posable that the heater core is clogged , or the door flappy thingy is opening enough to let enough hot air out to warm the cabin. fyi i drive ww/no heat or so know how you feel.

quick question are you losing coolant at all?

Cmdpapichulo

thanks for the tips im going to check as soon as possible its just work and the fact its like 15 degrees i dont wanna be outside lol...but there is no coolant loss will update thanks

Vashner

If both hoses are hot then it's probably flowing thru the core. Since you get heat in regular heat right probably looking like an issue with the flow control.

Cmdpapichulo

yeah both hoses are hot but the air really isnt hot its warm but i just bought a thermostat will change 2morrow then see and im gonna just disconnect the hose to the heater core and blow air threw it to see if its clogged hopefully that willl take care of it if it clogged

Cmdpapichulo

how yeah my side vent blow cold all the time i guess theres some piping missing under neath the dash im not really sure new to 1st gen

trochoid

iTrader: (6)

Need to close the side vent on the driver's side, that draws in fresh/cold air directly from the windshield cowl. The plastic lever that shuts this vent off often disconnects or breaks.

Cmdpapichulo

yeah thanks i changed the therm adn all the hoses are hot but i think im going to take out the blower motor and see whats up with that

1979mazdarx7

I wouldn't think it is the blower motor I would go with the heater core, those are more prone to fail on older cars.

JoeyMazda

I have a 1st gen.. Had the same problem. Before i purchased the car the previous owner had put the wrong thermostst in the car. They have the 170 and the 180. 1st gen requires 180 for the heater to work well.

Cmdpapichulo

do u think a 195 deg thermostat is to high

JoeyMazda

The 195 might be causing the problem. Try the 180.

Cmdpapichulo

no there is a 170 in there now but i was wondering if 195 would make everything better but if not ill put a 180 they also have a 192 but i dunno

JoeyMazda

Right there is your problem. It happened to me before with the 170. It's not opening enough to provide enough heat.Go with the 180.I just rebuilt an engine and put the 180 and it is working fine.

Cmdpapichulo

yeah i read that u did that but i wanted to go a lil higher thinking that it would help with the heat a lil more

Rx-7Doctor

iTrader: (13)

Joey,

Looks like I need to clarify things for you regarding the operation of the thermostat as it is often a misunderstood component.


You were not getting enough heat for the heater core with your 170 degree thermostat because the lower the thermostat temperature the less time the coolant stays in the block. Therefore you were having more cold water circulating through the engine keeping the temperature down. The coolant needs to stay in the block longer to build up heat especially during the colder times of the year when you need a heater. The longer the coolant stays in the block the hotter the water will be that is going through the heater pipes therefore allowing hotter air to be produced from the system.

When you went to the 180 degree it allowed the coolant to stay in the engine longer therefore producing more heat for the heater system. Putting in a 195 degree thermostat will increase the efficiency of the heater system because it will keep the coolant in the engine longer before the thermostat opens up and allows fresh cool water to cool the engine back down. This will not harm the engine and in fact the hotter a engine runs (without overheating) the more fuel efficient it is.

Cmdpapichulo

thanks DOC

Absent_Heart

Something else to look into, the hose spits in two as it comes from the block, one going to the oil cooler, the other to the heater core, the y pipe that reconnects them into one pipe has an orifice on the oil cooler line to prevent all the flow from going though the oil cooler, thus by passing the heater core. if the y pipe doesn't look stock (ie like some kinda pipe you could buy at home depot) id take the hoses off and have a look.

Cmdpapichulo

ill check dat out just been real busy thanks everyone 4 the info