No heat

[v8jeeptj]

Heater blows luke warm air.

Just installed a brand new thermostat and both heater hoses are so hot that you cant grab them. When I cycle the swithes in the cab they all seem to work fine but no heat.

Any suggestions

 

[doghead]

Heater core plugged. Flush or replace it.


CLR workes well to flush.

 

[Westech]

for what the flush agent cost and the cost of a heater core.. just replace it. You can get a core for about 20 bucks and they take about 25 min to replace.

Dh is right she prob plugged up tight like ah (Radio Edit) .

 

[Matt65]

If it worked before - Ensure there is no air in the system first. This can sometimes be more difficult than it should be.

 

[mikes47jeep]

are you sure the vent control in your heater box is working correctly? it could be stuck half way open

 

[Grega]

Pop down the glove box door and make sure that the air blend door is fully closing or opening. Loosen the screw that holds the cable and manually operate the blend door. See if that helps. Also, did you have good heat before the the thermostate replacement? May have air in the system, or maybe have trash buildup around the heater core. I do not think that the heater core is bad since the inlet and outlet hoses are both hot. But if you go through the trouble of taking every thing apart,you just as well change it along with the hoses. I also glued new felt around the air blend door because it wasnt sealing as good as it used to..

 

[v8jeeptj]

I never had heat it blew cold when I got it. I will try to manually operat the doors. How do I go about bleading the air out

 

[junkridge]

for what the flush agent cost and the cost of a heater core.. just replace it. You can get a core for about 20 bucks and they take about 25 min to replace.

Dh is right she prob plugged up tight like ah (Radio Edit) .

Replace in 25 min? Please share the secret on this repair mine blew last night!

 

[detroitmuscle1986]

Is your heater core an original copper one? When we first bought our truck it had an aluminum heater core, and like you said, only produced luke warm air. The hoses were hot, and all of the systems were working as they should. The only thing we figured it could be was the heater core itself, so we bought an original copper one on ebay and now she blows hot air like never before! Hope this helps!

 

[Reverend Evil]

Agreed the copper one is the way to go I have the aluminium one in there now and lets just say I am glad I live in Florida cause it only blows luke warm air also if you want it a little hotter you can up the thermostat but not sure if this is the right route to take I run a 165 year round but if you put a 195 in it will be hotter for sure but I would also check and make sure it is a safe temp.

 

[xenocath]

i think they come stock with 195 thermostats in these trucks.

 

[Kellyboy]

The problem with the aluminum ones is they let air pass around them instead of through the fins. You need to fill in the gaps between the box and core with something or go with the 94553 core from spectra premium at autozone.the picture below shows a stock copper core a cheap aluminum core and the spectra premium core. Check out the difference. You really need the air to get sucked through and not around the core.

 

[Kellyboy]

The problem with the aluminum ones is they let air pass around them instead of through the fins. You need to fill in the gaps between the box and core with something or go with the 94553 core from spectra premium at autozone.the picture below shows a stock copper core a cheap aluminum core and the spectra premium core. Check out the difference. You really need the air to get sucked through and not around the core.

Info and photo cred to jacksmad1

 

[Tinstar]

Mine was also blowing luke warm air this past winter.
I searched and found this thread months ago.

The air blend door was not closing all the way even though the controls were all the way to the hot setting.
Dropped glove box and removed the wire that controls the blend door.
While the hot was selected, the door was still about 1/2" open, letting in cold air.

Used needle nose pliers and adjusted wire to make it close all the way.

Result was nice hot air!!

Now when I select cold. It is
When I select hot, it is.
And works great in between.

 

[cucvrus]

May I suggest removing the heater control and the cables and putting a few drops of motor oil on the cable ends at the controls and hang them up until the oil comes from the other end of the cable. Put a few more drops of oil on the cables and work them controls back and forth then grease the slides on the heater control assembly and reinstall. It makes the entire system work better for years. I do it o every CUCV during my initial inservice. I have done it on vehicles that I inserviced 12 years ago and they still slide well. These truck are all 30+ years old. Old cables need some cable lube or motor oil applied. Good Luck.