Heater not getting hot?

Does the engine overheat now? If it does, there's most likely an air pocket under the thermostat that has to be bled out. If there's no bleeder screw, look for a threaded plug or a sensor on or near the thermostat housing that can be unscrewed. This video can help us fix it.

and this guide and video can help if its not a thermostat.

https://www.2carpros.com/articles/car-heater-not-working

and

https://youtu.be/SNRb6pSwYuU

Please run down this guide and report back.

No the engine doesn't over heat. In fact the temperature gauge is only about 1/4 if the way up. It's always been that way which kind of led me to thermostat.

Also when I first turn the heat on I get Agee second burst of warm air.

Feel the heater hoses after the engine has warmed up. They should be too hot to hold onto for very long. If they are, you might suspect a problem with the actuator on the heater box. Ford has had a lot of trouble with them on the Rangers in the mid to late '90s. I don't know if the other models use the same type.

If the hoses are not as hot as the radiator hoses, look for a water control valve inline with one of the heater hoses and be sure that is opening fully.

Yes before I changed the thermostat the upper House got slot warmer than the lower hence another reason I leaned toward thermostat. Now neither houses are getting warm. I hooked up garden hose and flushed then still n No heat and the houses aren't warning to at all near the firewall

Are you talking about the upper and lower radiator hoses? If those aren't hot, there's something wrong with the new thermostat. They don't fail very often so I'd look for it's not seated and sealing properly in the housing, or someone pried it open and it is stuck there. That just involves making sure the pin in the center is not popped out of position.

Did some more "testing" when I have vehicle idling or while driving and give it more gas "idle it up" the heat seems to kick in

There's two common causes of that. If the engine is not running hotter than normal, the coolant level is low and there's an air pocket in the engine. If the engine IS running hotter than normal, look for a slipping water pump belt, especially on engines where the timing belt runs the water pump.

Yes the engine is running VERY cool ( so the gauge says.) how would I go about bleeding it I've looked oblong and it says there's a bleeder valve next to the thermostat housing ( there isn't) hopefully that is the issue. Thank you very much for you responses they have help and probably saved me hundreds of diagnostic parts and labor.

Sorry to leave you hanging. Had another computer melt-down, but after a few hours, it's up and running for who-knows-how-long.

I don't think bleeding is the issue. Thermostats don't open in response to hot air. They must be hit with hot liquid. For that reason, an air pocket will result in overheating. You have the opposite. Use a special hose pinch-off pliers or fashion something with a pair of wood blocks that you can use to pinch the upper radiator hose. That is doing the same thing as the thermostat does. If you see the temperature come up after a few minutes, suspect your new thermostat.

Thanks a lot!!! I'll try that as soon as I get out of work.

No doesn't overheat (unless didn't leave it clamped long enough) when I first turn the heat on I get a burst of heat then just very low heat. When I keep the Rpms up in neutral or park it has good heat

Sounds like you're not getting enough volume through the heater core, but not because it's plugged. If it was plugged, you wouldn't get higher temperatures when raising engine speed. The initial burst of hot air says the hot coolant did circulate through the heater core but it's cooling down right after you turn on the fan and draw cold air through it. Is there a water control valve inline with one of the heater hoses? I hope I didn't ask that already. I'm working with a few other people with heating problems, and I can't go back to page 1 of this conversation to reread it.

I don't see a water control line next to either house by the firewall. However I did notice something else as I was shoveling the foot of snow we got here I moved my truck and didn't turn the heat on (must have forgot) either way I decided to check the 2 houses going into the firewall and both were actually very hot usual just the upper is. So like a optimist in thought wrote it fixed itself. No such luck I hoped in the truck hit the vent floor option button heat for about 20 second then...... Nothing also the lower heater house by the firewall cooled right down. Don't know if that gives any obvious options or not but figured I'd toss that observation out there. Also did I mention it has the digital heat controls I've even tried turning the"max ac" on and setting temp to 90. No luck trying everything not to have to bring it to a mechanic out here since i just moved about 2 hours away from my home town and don't know any. But with a 4 month old and a 5 year old heat is beginning to be needed sooner than later it was a blistering 13* today.

Everything you've said points to insufficient volume through the heater core. The second heater hose really won't be noticeably cooler than the feed hose. When it is, it's because too little hot coolant is going through the heater core, and what is getting through has plenty of time to be cooled down. I think there has to be a restriction somewhere. As I recall, you said there's a new heater core in there already. Still, I would disconnect both hoses, then run water through the heater core, then both hoses, with a garden hose. The water must flow easily through each hose without building pressure and spitting back as long as the radiator cap is off. If you find the water doesn't flow through one hose, check if it's hooked to a metal pipe pressed into the intake manifold. Those are made of very thin steel, and when they corrode, a part of it could flop over and block coolant flow.

So my 1999 ford explorer limited six cylinder 4,0 SOH has no heat. Well it gets sorta warm. The AC works great. But with winter time in central New York and a four month old. New born and a five year old heat is a necessity. I've changed the thermostat hoping that would be it. The temperature gauge in the vehicle also stays real low not even close to half way between c and h so I'm guessing that has something to do with it. Any help would be greatly appreciated. This site and everyone on here has been a tremendous help with any issues I've had. So thank you all.

Your thermostat may be faulty (stuck open all the time) just because it is new better re check it, also with the engine as hot as it gets feel that both heater hoses are hot to touch, if not you may have a blocked heater core, start here.

I had a thoughtnthe thermostat may be faulty. (Hopefully) will check the hoses as well. The hoses your talking about bare the ones near the firewall correct ? I've heard the heater core is an bear to change in the truck. (Taking apart whole dash possibly?) Thank you for your response will post back when I have checked theses option provided.

Yes check the 2 hoses entering the fire wall, these are the heater hoses.

Upper heater hose is quitenanbit hotter than lower.

i had my sister replace fuses cause only rear heater worked. then afterwards she said front heater only worked after reaching speeds over 50mph just wondering what the problem might be.

its a possibility that your heater problem is relayed to you coolant. you should check your coolant level and condition. if that turns out to be good then you should check the operation of the plenum blower motor. just turn the fan on and check and see if it works at all different settings. also at the same time change the setting on the directional control knob to each of its settings. also make sure that the vehicle is warm and that the coolant temperature gauge is reading warm as well.

You may have a part blocked heater core, try flushing first.

How would I go about that also just noticed whole sitting out in the truck idleing with the heat on there is an on and off "growling" noise. Stops when I turn off heat

Take heater hoses off and use a garden hose to see what flow is through the heater core, the noise may be an air lock in the system, you will need to make sure all air is bleed from the cooling system as well.

Engine does not overheat,new t-stat, hoses hot. Heater blows cool air. Am told either brkn door on heater box or bad actuator. The process to replace the box is prohibitive. Can the actuator be tested and easily replaced?

You have to go behind the dash to check -could be an air mix/ blend/mode door that is not opening or an actuator/vacuum and hose problem.

engine temp keeps rising and falling no cabin heat

low coolant level, bad thermostat or possible blown head gasket from overheating

Roy

ok i've already replaced the therostst and the coolant level is good. engine is not over heating. thinking maybe a bad therostat again. temp gets in the working zone then drops to cold and incresses over and over again. cabin never gets warm

My heater is blowing cold air,

I replaced the Control Panel, flushed out the two hoses that go to the heater core assuming it might have been cloged, replaced the thermostate.
Checked to see if I had any leaks where the heater core is located and there was no dampness & no smell.

Thank you for your help,

Brian

Hello –

So was it working fine and then all of a sudden not hot air or was it gradually getting cooler and cooler then quit?

How does the temperature gauge of the engine read…..normal?

With the engine at normal operating temperature….feel both heater hoses going into and out of the firewall………do they both feel hot or is one colder.

What is your engine size in liter?

The Heater stopped suddenly!

Both hoses going to the heater core are very warm!

I noticed that the heater core compartment under the glove compartment was warm and still blowing out cold air, the blend door is working correctly.

The temperature guage is working correctly, we just replaced the termostate last week becasue the temperature was reading very cold!

The engine is a V-6 4.0 Liter

Could it be a sensor on the water pump?

Please advise and thank you for your help in this matter,

Brian

Hello - Thanks for the info Brian To me, I lean to the control panel or blend door area.......my reasons.....see what you think.. You said you flushed the heater core hoses, so I assume that means you flushed the heater core and had good water flow from both sides of the core. That would indicate the core is okay. The temp of the vehicle was very cold.......you changed the thermostat.....heater was working fine......temp of engine.....fine. That would indicate again, the heater core is working okay and the water pump is working okay. Why did you replace the control panel.....do you have an automatic or manual system.. How are you verifying the blend door is working as it should? Are you sure the connectors are definitely secure on the back of the panel since you had it removed and or there are no wires pulled out. Also, that there are no vacuum lines that came disconnected or split when you removed it. Then you said it just stopped.............. Now the only thing that may point to the inlet control valve or possible poor cooling system operation is you said the hoses were warm. The hoses should be too hot to handle. Here are some tests for you............... Here are some tests for you for insufficient or erratic or not heat.

The heater blower works properly, the air does not heat. It appears the blend door is not working. How do i confirm that is the correct diagnosis. What else could cause the failure to heat?

Have you checked for a sticking thermostat, a clogged heater core or the heater control valve???

Thank you! The engine builds heat, and maintains a constant temp, so im not thinking its the thermostat. But i did not consider a clogged heater core or a stuck valve, thank you! Im thinking its time for a trip to a pro to make sure. This truck has an electonic thermostat that is manipulated from the steering wheel. The air switched from defrost to heat to vent as dialed. The air cond also comes on as dialed, so the control valve or clogged heater makes sense. What does make it sound like the blender door is that it made a popping noise (according to the former owner) at random times which caused the air to turn warm. ANY further thoughts would be extremely welcome, thanx!

I have a 1999 fod explorer. I have had no previous problems with the heating/cooling system. I smelled anit-freeze after driving to work and opened the hood to find anti freeze spilling out from under the radiator cap. There were no leaks in the upper or lower radiator hoses, and no leaks in the radiator itself. That morning I had heat in the vehicle, but since that incident, there is no heat, and can only drive short distances before I start smelling the anti freeze and it starts coming out again. There is plenty of anti freeze in the vehicle, and the top hose was hot to the touch. The temperature gage gets to where it belongs, half way between cold?hot, and stays there. Wondering if you could tell me if its a water pump, thermostat, other? Thanks.

Need to pressure test the coolant system ,checking for leaks
when engine cool open and check coolant level in the radiator
start cold engine and check coolant in radiator
if all OK and no heat inside
check heater hoses by firewall if both hot problem is inside heater box and suspect blend door actuator