Archived Heater will not work. Im FREEZING!!!!!!!!!

[myoldodge]

My early 98 12vlv i just bought is about to freeze me to death. I work in north dakota, needless to say it gets alittle cold here. I have replaced the thermostat and have plenty of coolant. Motor temp is 180 deg but very little heat from the vents. I have blocked the grill with no results. With the fan on the 1st and 2nd setting it will blow warm until i reach highway speeds and then it freezes me out. The higher i turn the blower's fan speed the colder it gets. Can someone please help me find the problem.

 

[Missouri Mule]

It seems your blend (temp) door is stuck, either the actuaor is not working, or the door is broke.

Try turning the control knob to recircualtion for now see if that warms up the truck unitl you can check out the blend and recirculation door. (The Recirculation door could be held open by debris. )

 

[myoldodge]

Can you tell me where its located at? And how to fix it.

 

[Sticks]

Verify that you are getting flow through the heater core. Both hoses should be hot when at operating temps.

 

[Bill Stockard]

If you have access to a vacuum gauge, disconnect one of the vacuum lines under the hood to check the vacuum with the engine idling. The reading should be somewhere between 27 and 30-In/Hg. The heater doors are operated by vacuum servos. A common location for vacuum hose failure is where the small hose enters the cab above the exhaust manifold. If your truck is a 4x4, check the vacuum hose connections at the transfer case and at the vacuum servo on the front axle.



Bill

 

[Sticks]

If you have access to a vacuum gauge, disconnect one of the vacuum lines under the hood to check the vacuum with the engine idling. The reading should be somewhere between 27 and 30-In/Hg. The heater doors are operated by vacuum servos. A common location for vacuum hose failure is where the small hose enters the cab above the exhaust manifold. If your truck is a 4x4, check the vacuum hose connections at the transfer case and at the vacuum servo on the front axle.



Bill

IIRC if there is a vacuum loss, that would default the vent doors to defrost only, not sure what that does to the blend door. If he has vent control (floor, dash, defrost) then the vacuum is working.

 

[The patriot]

I wrapped pipe insulation around my 2 steel lines along the exh man and it helped a bit.

Problem was when I ran it hard the pipe insulation began to melt. #@$%!

So then I got a large piece of high heat gasket material out of the dumpster @ work and re wraped the pipes. It didnt melt then and the heat was OK. Not great, just OK.

I'm in NJ it dont get as cold as where you are.

HTH

 

[bobheller]

If both hoses are not hot the heater core is plug up try unhooking the hoses and flushing it with some water pressure or air pressure becarefulwith the air

 

[K.L.Schumacher]

heater not working

I was in Saskatchewan in December of 2009 and i went through a short spell of minus 30 Celsius. Once i got my truck started i went for a drive and the only winter prep i did was partially block the rad. I was always warm in my truck despite the cold . No other changes were made to the heating system. I did have a problem with dash control and i seemed to narrow it down to a Short multi tubed line hooked to the dash switch. I had a spare so i changed it out. I believe it had a blockage as i had vacuum coming from the motor to the line junction under the dash. Kim

 

[SMorneau]

when i was daily driving my 96 I would wear insulated bibs and pac boots, just like ice fishing, even when my truck would warm up it would get cold if traffic stopped. It was a 50 mile drive one way to work and sometimes it would never get what some would call warm. Take that for what its worth from your neighbor in MN.

 

[mopars1]

I second back flushing the heater core. I bet that will fix the problem. Let us know if you have found the problem.

 

[rkressg]

Just to update this post, my truck suffered this exact same issue a few weeks ago. The Heater core was almost completely clogged.

I used a Garden Hose and Hot Water to get the junk moving. I figured it would either blow the junk out or blow up the heater core under my dash.

When I ran the hot water through the unit (I did it in both directions, backwards first), I had chunks of black crap come out of the heater core. I normally flush the cooling system every 2 years, so I was floored by what all came out.

After getting a decent amount of water going through the heater core, I re-connected everything, and did an entire cooling system flush using MACs cooling system flush (from NAPA).

I refilled the system with new Red Antifreeze (I did not have any Cummins Anti Freeze sitting around), and distilled water.

The heat works like a champ now, and I did not have to remove the Dash