Please help! Heat doesnt work!

[em5568]

Alright guys, so i checked my hoses and the heater control valve. After the car warms up to running temperature (around 210 on my cluster gauge) the two hoses get very close together in temperature, but it just doesn't seem hot enough. Im getting flow through the control valve in both directions, but the coolant hoses/heater core in/out only get around 110 degrees unless i bring it to around 3000rpms. In which case it still only gets to around 130 degrees, is there potential i just didnt burp the system enough?? it doesn't use any coolant and its been close to a month since i last replaced anything in the system.

 

[em5568]

Okay guys, Update.

Today i got frustrated and decided to start from square one, to make sure everything is functioning properly in what i've replaced.

I took out the tstat and temp checked it with hot water, it opened at 195 degrees. So thats good.

I'm getting flow through my heat control valve and the lines to and from my heater core, all lines are NOT clogged. I ran through all of them and then properly burped the system. All lines get hot.

Now, that being said. The heater core will get HOT at operating temperature. About what i imagine it should be, -BUT- as soon as i click on the fan it cools it off INSTANTLY. i mean, INSTANTLY back to ice cold....I'm stuck..Is there potential for outside air to be getting sucked in and cooling it off right away considering it's about 10 degrees out? Like perhaps a door is stuck open?


...thanks guys..

 

[east302]

When the heater core is cold and the blower on...

How do the lines at the firewall feel, both up and downstream of the heater valve?

Is the plunger on the bottom of the heater valve pushed up (in) or down (out)?

Does the plunger freely move with the ignition off?

Does the plunger freely move with the ignition on and temperature dial set to anything but the max cold detent?

 

[em5568]

Up and down stream of the heater valve are roughly the same temperature, they get to around 98 degrees (By lazer thermostat testing). hand feel they feel roughly the same temp aswell.
-The plunger on the heater valve is fully extended down
-The plunger does move freely with the ignition off, it does not move at all unless it is on max cool.

 

[east302]

-The plunger does move freely with the ignition off, it does not move at all unless it is on max cool.

So if it is on max cool, the plunger is up (valve closed) and when it is on any other dial setting the plunger is down (valve open), correct?

 

[em5568]

Yessir

 

[east302]

So the valve is functioning correctly, then. With it closed, you should be able to feel a difference between the upstream and downstream hoses. If you're seeing them cool when it's closed and warm back up when it's open, then the valve should be good.

Just to make sure that I read this right...so you have the bottom cover removed and can feel the core. It's hot when the blower is off. As soon as the blower is turned on, the actual heater core surface temperature drops to ambient or thereabouts? Is that what is happening?

The only damper that brings in outside air is the recirculation, located above the blower.

Can you verify that the temperature actuator is turning? The silver dial should rotate approximately 90-degrees from one end to the other.

The thermostat is opening when installed, correct? The upper radiator hose is getting hot? The heater hoses should be comparably hot to the touch.

 

[sumo]

Still could be trapped air in the system somewhere. Have you tried Jacking the front of the truck up with the cap off? It can help trapped air make its way to the top. Personally I have and use a vaccume coolant filler. It puts negative pressure on the coolant system, it also doubles as a leak detector because with the valves off, it should hold the negative pressure.
Once you open the valve to let the coolant in, the negative pressure sucks it I’m leaving no chance for air to get trapped. Also great for vehicles with rear heaters.

 

[em5568]

Yes, the valve is functioning correctly. When the plunger is down, the two lines are roughly the same temperature after the truck begins to warm up. When the plunger is up, they begin to cool.

Yes, i currently have the bottom cover removed exposing the heater core. When the blower is off, it begins to warm up. after I rev the engine for a minute or two it will get extremely hot, but once the blower is put on it cools it off completely within seconds (Keep in mind it is about 5 degrees here, but i still dont see how it could possibly cool it off THAT fast).

Yes, the tstat is opening at operating temperature. I removed it and double checked the opening point with a laser thermometer. It opens at 195 degrees and the top line does get hot after the truck is warm.



I have also had the truck jacked up in the front, with a coolant bleeder funnel up top filled to try to release the air bubbles (If there are any) and i did it in 15-20 minute increments roughly 4 times to try to get all the air out.

I will have to double check the actuator, i can remove the glove box and see it pretty easily. Do you have a diagram for where the notch on the actuator should be at each position?


- Thanks
E

 

[east302]

I've never opened up the heater core portion of the box, so I don't know, but can you see the air door in it? I guess blowing 5-degree air over it would cool it down, but I would think that it needs the cover installed to warm the air?

I don't know which dial position corresponds to full cold and which is full hot, but it has to be one for each extreme. There should be small indicator lines in the plastic.