[RESOLVED] No heat after thermostat install?

[Gee-Es-Tee]

That's right... I ran the car during the summer without the thermostat after the engine rebuild. No problem- but now since it's cold, I NEED heat. I went to Autozone and purchased a thermostat for my 95 GST. I installed it, and still... nothing. It gets hot, but it takes a loooong time and it's not "heat" by any means, just slightly warm air and this does not suffice during the freezing nights when I get off work.

Is there anything else I should check, or did Autozone just sell me a crapola thermostat?

 

[assault187]

last one I picked up from Autozone it was BAD, I had the same exact problem. For some reason or another it got stuck open after the very 1st heat up. I'd say pop it out and check it.

 

[Old Mitsu Tech]

Well, you need to feel the hoses going into the bulkhead. If they are hot, and one will be hotter than the other, you may find your blend door is not sealing right. First verify that the engine is indeed getting up to operating temperature. A no contact thermal gun is great for this. If that part is good, go to the heater hose inlets where they go into the passenger compartment. Those both should be hot. If not, then you may have a blocked up heater core. You can try back flushing to see if that removes the blockage. If you heater core is junk and you put too much pressure on the back flush you will cause it to leak. Which brings me to an old saying. " If it jams, force it. If it breaks it needed replacing anyway" 'o) If the heater core is doing its job, you might look into the heater controls. More specifically the blend door actuator.

Good Luck

 

[Gee-Es-Tee]

Wow. Thanks for the great replies! I will check everything as soon as I can. I appreciate the wise words!!!

 

[viprez586]

Try "Burping" your cooling system. With the engine cold open up your radiator cap and squeeze the lower radiator hose, if air bubbles come out, thats your problem.
I like to do this, and then start the car up with the cap removed and wait until its at normal operating temperature and coolant will start flowing through the engine, continue to squeeze the lower hose and see if you get more bubbles out of the system.

Also, if you run no thermostat to keep your car from overheating. FIX THE PROBLEM!
Check and make sure your thermostat is installed the right way as well.

 

[Defiant]

DSMs -unlike rolling abortions from GM and others- have no vent caps on the cooling system, and need no burping. Provided the cooling system is healthy, with no collapsing hoses or leaking joints, a DSM with a full overflow tank will flush out all its remaining air in the course of a half-dozen heating and cooling cycles.

 

[Gee-Es-Tee]

still no luck... the thermostat is acting correctly, the engine comes up to normal operating temperature, and all hoses are hot. hrm...

 

[turbobird14]

it has to be something blend door/heater core related... the blower fan blows air across the heater core, kind of like an inside radiator, and that now hot air goes into the vents. thats the warm air you feel. are you sure you have enough coolant? dumb question but sometimes overlooked

 

[Gee-Es-Tee]

definitely enough coolant. I checked for all of the obvious earlier today. It perhaps may be the heater core. I am finally off today so I can spend some time to figure out what's wrong.

So now I am off to locate something online which tells me how to check the heater core...

 

[Defiant]

Two FAQs to get you started:
http://www.dsmtuners.com/forums/fre...3-heater-trouble-air-coming-out-isnt-hot.html
http://www.dsmtuners.com/forums/fre...276212-heater-trouble-blower-not-working.html

 

[Gee-Es-Tee]

Thanks- I'm going to try to clear out the heater-core before I attempt to remove or buy another one. At my apartment, we do not have a water hose for our personal use, so it's a bit hard to do it where I am, so I will attempt this around Christmas time. *throws blankets in car*

So if THAT isn't the case, I will just have to purchase an entire new unit... hmph.

Everything else checks out just fine, so this is the only thing left.

 

[Supa Dexta]

You may be able to fashion something up with say a 2L pop bottle, and give it a hell of a squease to blow thru the core, several times even.. Not that I've ever done this, but in a pinch it may work.. Hell they work as a plunger..

 

[asexton6969]

do the easiest thing, boil the thermostat and make sure it opens. Then proceed from there, not very common but they do fail sometimes 1st try.

 

[Old Mitsu Tech]

If the engine is up to operating temp around 190 degrees farenheit, there should be no reason for the heater to be malfunctioning except you do need to check the inlet and outlet hose to see what their temp is. If they are also hot to the touch and one should be slightly cooler than the other due to heat transfer through the core. That means the core is operating properly. The other problem and it was mentioned in here by a couple of people to look at the blend door actuator assembly. If the water is doing its part and you're cold, the blend door is your only other real obstacle.

Good Luck

 

[Gee-Es-Tee]

Thanks for all of the great replies. I'm taking care of my dilemma this weekend when I go home for the holidays. I'll post what the problem was and how I fixed it for future reference for someone else.

Today was incredible-- I fixed the heat issue. The culprit of my woes, you ask...? A clogged heater core. I guess it became clogged after the transition of my rebuilt motor into the car. I unhooked the two hoses running through the firewall and made a fancy nipple thing for a water hose and backflushed it. Crap shot out of there that I couldn't believe. Good thing it was nothing else major. Now I'm all warm and toasty.

Woohoo!

 

[Old Mitsu Tech]

Nothing like a proper "fix"