Heat stopped working

[kenz5380]

I drive my M1008 every day. I replaced the radiator a few weeks ago so that may have something to do with it, but this morning the heat would just blow cold air. I reached under the hood and both heater hoses were cold. Is it possible this is just a bubble in the system somewhere? Someone said that there was a vacuum actuated valve that allows the coolant to flow to the heater core. I honestly haven't had time to even look under the hood in the daylight about this, but its getting pretty cold in the mornings so I need to figure it out.

Any Ideas?

I searched the previous posts, but haven't turned up anything.

 

[Westech]

there is NO valve in line with the heater hoses. Only trucks with AC have the valve. If the lines are cold you might be low on coolant, or the heater core plugged. If the lines were hot and still blowing cold the air diverter door might be stuck in the dash.

 

[doghead]

I'd bet Air in the system.



Remove the radiator cap(use caution) and let it run until the thermostat opens, top off if needed.

or, If you remove the cap and you can see it is lower than your heater hose, fill it, then run it with the cap off unti it gets warm.


If that doesn't fix your problems, get a tattoo...

 

[steelandcanvas]

get a tattoo...

Tatto, yeah that'll do it.

 

[Westech]

Hey.. are you trying to start something DH?

 

[hilber]

Sounds like it is low on water(not enough to get to the heater)

 

[kenz5380]

So I had a look at it in the daylight after it cooled down from the drive in this morning and low and behold... there's hardly any coolant in the whole dang thing! I can't believe it. A Month ago I had a new radiator put in at the dealer. Do you think they didn't fill it enough? I park in a clean concrete lot every day so there is no way I could miss all that coolant running out onto the ground. I added 2 gallons just now and it still had room. There isn't any steam in the exhaust, nothing on the ground when I park, where the heck did all that coolant go? Or could a dealer really add 2 or 3 gallons less than my system requires?

 

[tamecrow]

So I had a look at it in the daylight after it cooled down from the drive in this morning and low and behold... there's hardly any coolant in the whole dang thing! I can't believe it. A Month ago I had a new radiator put in at the dealer. Do you think they didn't fill it enough? I park in a clean concrete lot every day so there is no way I could miss all that coolant running out onto the ground. I added 2 gallons just now and it still had room. There isn't any steam in the exhaust, nothing on the ground when I park, where the heck did all that coolant go? Or could a dealer really add 2 or 3 gallons less than my system requires?

You need to pressure test your cooling system to find out where you're losing the coolant. If you don't have a radiator pressure tester, you can make one.

Make an Auto Radiator Pressure Tester

 

[Midnight Rider]

Check your oil level lately?

I thought it was possible for coolant to get into the oil under certain events.

 

[kenz5380]

I have checked the oil level, yesterday. There was no visible coolant in the oil and I was about a quart low. That is pretty typical for my truck.

 

[Midnight Rider]

I guess the other possibility is that when the radiator was replaced they thought they had it filled up. Perhaps air bubble or something blocking it from completely filling back up. Then you drove it and the coolant went down.

I don't remember how much the radiator itself holds, but the block holds more.
I don't remember how much I put back into mine after I replaced the radiator awhile back, but it was quite abit.

I'm surprised if it was that low that you didn't see the warning light come on in the cab.

 

[kenz5380]

I guess I need to install that temp gauge I've had in the garage forever. I may have done some damage to my engine. I don't think so, but who knows. The idiot light may not have been working at all.

 

[deercoker]

hoses are warm

I have checked the oil level, yesterday. There was no visible coolant in the oil and I was about a quart low. That is pretty typical for my truck.

If the hoses are warm could if be the blend door in the dash and where exactly is it?

 

[cucvrus]

Right under the dash behind the glove box and the other is in the center of the lower dash area. i have seen the cables get stuck and bent. Remove the control assembly and get the cables lubed up well.

 

[deercoker]

Thanks cucvrus, I will check'em and let all know tomorrow

 

[deercoker]

well the cables are moving freely and you can hear the doors opening and closing, bad heater core maybe?

 

[cucvrus]

Possible. Do you have a thermometer that you can measure the temperature of the coolant when it is hot? It could also be a rodent nest in the duct work or the fan housing area. Heater cores usually leak when bad. If both hoses are hot that means circulation is taking place. I would check the duct work. Then just check the heater core with fresh water hose after you pinch off and remove the heater hoses. Did you check the coolant level? I am just guessing but trying to help. Good Luck.

 

[deercoker]

I don't have a thermometer to check coolant temp, funny thing is I drove it back a couple weeks ago fro Chattanooga where I bought it about 3.5 hour drive and the heat worked fine, the guy I bought it from told me the heat did not work so it surprised me when it did. However it has not worked since I have brought it home and drove it some, I think I will check the ductwork for rats nests.

 

[cucvrus]

Are you telling me that it has heat on the highway but not when you slow down and drive in town?

 

[deercoker]

I guess you could say that, worked fine on the interstate (for a cucv) but not sitting or a lower speeds, have not had it over 50 mph since I brought it home, the coolant level is good and appears to be clean.