# No Cab Heat



## mayhem (Aug 25, 2006)

So today's subzero temperatures really got to my truck...I've got almost no heat coming out of the vents. Checked the lines under the hood and the return line from the firewall was stone cold. Am I right in thinking my heater core is pretty much plugged up?

I had slow heat late last winter combined with a low temp gauge, which I figured was a abd t-stat...replaced it, burped the lines and the problem went away.

This year, its worse, but the temp gauge reads normal and the coolant lines are all hot. I had a local place do a flush and fill and it helped significantly for about a month, but now its virtually no heat at all.

Gonna call the local radiator specialty place tomorrow, anyone have any other ideas to try that won't run me a kajillion dollars?


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## scitown (Dec 9, 2007)

I just sold my old 1990 flare side z71 to a friend. He lost heat in it about a month ago. He said he somehow cleared the lines with compressed air. Blew a big plug of crap out the return hose. He said it was like playdoe. Hope it can be cleared and It is not the heater core good luck.


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## ahoron (Jan 22, 2007)

try to back flush the core with a garden hose. remove the hoses from the heater stick hose in return side.or compressed air like scitown said.good luck


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## Plowinpro03 (Dec 18, 2007)

ahoron;477574 said:


> try to back flush the core with a garden hose. remove the hoses from the heater stick hose in return side.or compressed air like scitown said.good luck


I did that with a pressue washer one time...deff. cleaned out the core and my cab along with it......

To answer your question in short, its most likey the heater...quick fix....try kicking hard under your passenger side dash and see if it loosens up a little....


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## sechracer (Nov 4, 2007)

If you can hear the blower motor running, the fan itself is fine. With one side of the core being cold, its definitly plugged. The garden hose works great, I do not reccomend using air as if you cant get it to push out, you could crack the core, and then you have to replace it. Useing a garden hose, remove the hoses from the core (or the other ends if easier to reach, but make sure they are the ones directly to the core), flush the water through the cold side first. When the water clears up, fush back through the other way. Do this a few times, and then hook everything back up. Refill the system, burp it, and refill it again. Warm up the truck and try it.

OR replace the heater core....... your choice.

Tom


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## mayhem (Aug 25, 2006)

I think I'll try the first option first.

Thanks guys.


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## sweetk30 (Sep 3, 2006)

if dex cool first get rid of it now !!!!

then flush heater core with garden hose. we do it all the time at work. 

that dex cool needs to be installed up the enginers arsh till he is toped off.


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## pyro29 (Dec 7, 2007)

sweetk30;478022 said:


> if dex cool first get rid of it now !!!!
> 
> then flush heater core with garden hose. we do it all the time at work.
> 
> that dex cool needs to be installed up the enginers arsh till he is toped off.


Second that! Every vehicle with dex-cool is a clogged core waiting to happen.

And a leaking intake gasket...and a bad water pump...and a crusty leaking radiator...


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## Plowinpro03 (Dec 18, 2007)

pyro29;478149 said:


> Second that! Every vehicle with dex-cool is a clogged core waiting to happen.
> 
> And a leaking intake gasket...and a bad water pump...and a crusty leaking radiator...


The dealer wouldn't even be able to say it better for themselves...dex-cool...a failed attempt by GM...


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## scitown (Dec 9, 2007)

Did you flush it out? Let us know how you made out.


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## mayhem (Aug 25, 2006)

Flushed it out this morning...plug of nasty crap came out of the core looking for all the world like a cup of black coffee. Flushed it in both directions twice through the core, water was clear running through. Reconnected everything and fired it up...had warm air in the cab inside of 5 minutes.

Thanks for the help guys...hopefully it will stay in good condition and this isn't just the beginning of the disintegration of my heater core...but at least I've bought myself some time.


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## B&B (Nov 4, 2006)

mayhem;479341 said:


> Flushed it out this morning...plug of nasty crap came out of the core looking for all the world like a cup of black coffee.
> 
> Thanks for the help guys...hopefully it will stay in good condition and this isn't just the beginning of the disintegration of my heater core...


 The blockage isn't from the deterioration of the heater core, it's from the break down of the Dex-Cool... So you should be good on the heater core and it should last a long time...


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## jjtmarineb2 (Dec 17, 2007)

Please tell me you flushed the rest of the old coolant out after clearing the heater core! If not, expect it to happen again. flush the whole cooling system with water until clear and then refill with the green ethylene glycol. Yes you can do this, you just are not supposed to mix the two.  all around!


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## mayhem (Aug 25, 2006)

Didn't think of that.

I didn't flush the rest of the system out because I just had it flushed and filled with green stuff. Hopefully the contaminants were built up in the heater core and the rest of the system is reasonably clean.


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## sechracer (Nov 4, 2007)

mayhem;480238 said:


> Didn't think of that.
> 
> I didn't flush the rest of the system out because I just had it flushed and filled with green stuff. Hopefully the contaminants were built up in the heater core and the rest of the system is reasonably clean.


You should be fine.


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## scitown (Dec 9, 2007)

Thats good to here. Cheap fix. Good luck


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## In2toys (Jan 25, 2006)

So I'm ASSSSUMing the above fix would more than likely work on an 83 Chevy k20 with the same no heat deal.


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## MAR4CARS (Oct 6, 2005)

In2toys;677273 said:


> So I'm ASSSSUMing the above fix would more than likely work on an 83 Chevy k20 with the same no heat deal.


Will work on anything that has a plugged heater core provided whats pugging it comes out.


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## carl b (Dec 28, 2006)

I'm having the same problem in my 94 Chevy . this fall I replaced the thermostat. this spring I did the line from the manifold to the core . today I had the core flushed . It worked in the heated shop but with in a 5 mile drive it was cold . I need to get it fix now I have to plow tonight . my temp is reading 190 when it was 20-30 outside now it 0-10 it reading 150.


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## carl b (Dec 28, 2006)

anyone I'm lost here . I'm running out of things to try .


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## carl b (Dec 28, 2006)

just in case some one uses the search button here .

Mine was a easy fix . took the ducks apart saw a small clip had let lose on the heater core . and it was sitting on the bottom of the duct . re-cliped it bam i had heat .


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