Heater Not Blowing Hot Air

[MDewell]

hey gang..been awhile since I've been in here, but I'm at a loss, and you guys rock at this kind of stuff...

Problem is, it was 15 degrees this morning driving 30 minutes to work...and no hot air! I froze my tail off!!

The water pump has been recently replaced, and it was blowing hot air before that...I don't believe it to be the heater core, because I don't have any fluids on my floorboard...

The blower motor works fine..it's just not blowing hot air.

The temp on the gauge does the whole windshield-wiper deal..up, down, up...maybe a bad thermostat? Would that affect the heat this bad?

I do have a small pinhole leak in the tanks on my radiator that I noticed when the radiator pressures up, but what I've been doing to buy me time is top the radiator off, then fill up the coolant reservior. I topped both of these off this morning, and it will typically get me by for about a week before I have to do it all again. I know...get it fixed. I'm tryin...but times are tough. But, it's been working good this week, until this morning.

I should mention, if it helps, that this is the coldest morning of the year, so maybe cold has something to do with a damper or something not moving because it's cold? Make sense?

Anyways...I'll check in later to see if anyone has any ideas.

 

[boggs1227]

i'm going to say maybe the truck did not have time to warm up properlly at that temp .you said the guage does the windshield wiper thing "up-down"?do you mean the guage goes to it's fullest mark then back to absolute cold again? (if the guage is accurate then this is not good because at this temp and the motor almost over heating is a combonation for cracked heads or block) here in georgia where i'm located (about 100 miles from s.carolina) the temps have been cold but not like 15 but still my truck when started cold and after waiting a minute or two of running ...i can head out and it takes the guage about 15-20 maybe shorter to get to it's normal temp .so i thinking that yours just did not have time at that temp to warm up.

can you let the truck sit at idle long enough to feel heat being blown? what is the temp rateing of the thermostat?

 

[MDewell]

I let it run once I started it for about 5 minutes and then it took me about 20 minutes to drive to work on the ice/snow...the temp on the thermostat is 190 I believe..it's been a year...LOL

The gauge goes from about the "A" in Normal...down to the "O"....that'll show ya what kind of swing it does.

 

[BIGHVM]

Could just be an air lock mate, system needs to be run with heater on full for at least 3 cycles of the rad fan, then the fluid should have moved the air out.......let it cool and top up....After that you should see the heat is back in the cabin.
Good luck!

 

[boggs1227]

darn... i was just about to suggest that lol.....i got done typeing and posted and then thought about it a little more .but he's right did you burp out the air in the system when filling? many have ways to "burp" the radiator but the method i use is takeing the cap off , upper rad hose and pinch or squeez it till you see the coolant go down ...doing this several times will make the level in the radiator go down enough to add more coolant(maybe a inch or 2) .several times of this and driveing and doing it again have produced good results for me getting the air out when i did any type of work to the coolant system .

 

[MDewell]

OK I'll burp her tonite when I get home from work...what puzzles me is that it worked driving home last night, ya know? I wonder if the cold is affecting that door-fix that's on here...like it's too cold to switch over to the heater core air or something.

 

[boggs1227]

i think our heater doors are cable operated ( don't quote me tho) and not powered by vac power from the engine.

knowing my luck it's is vac operated

good luck let us know how things turn out for ya .

 

[MDewell]

Question..on this door fix thats all over here...which way should the door be for heat? I'm going to check on this as well because I can't honestly say I can tell if the door is opening or closing to allow the air to blow over the heater core, so i'm gonna spend about 10 minutes to tear into it and see....but not sure where I need the door to be for heat.

 

[Robrt32]

Mine has a vacume operated valve on the heater hoses.. I had to take a piece of bailing wire and tie that valve open.. Like a oven in there now.. I would check that valve to make sure its open or not clogged up

 

[MDewell]

ok I burped her on my lunch break and topped off the radiator.. still no hot air.

I did, however, top off with water, as I just added straight antifreeze this morning..don't know if that matters, but I did put about a quarter-gallon of water in it..

the more and more I play with it, i think that door is the issue, because when I change the air from cold-hot..i don't hear anything move.

 

[MDewell]

Think I found the problem..

went tearin into it really quick and after checkin around, saw that it appears the cable that attaches to the temp selector is broke off. In other words...it's not attached..LOl

I'll keep you all updated.

 

[Danimal86]

mine did the same unitl i hooked a hose up to the heater coil line, and flushed it (really nasty water came out).... there is a valve that regulates the amount of hot water flows through the heater coil...it is controlled by a vaccume line....i just disconnected the vaccume line and it blows HOT air now...good luck!