Heater stopped blowing hot air. engine won't idle hen hot

There are basically two types of whistle noises.

* Whistle when you get more gas (increase RPM, put gas pedal, sometimes just idling but louder when you put more gas)
This usually intake-side leak.
Intake manifold itself, intake manifold gasket (most likely), even airfilter housing, Airflow meter housing (connector), anything where air goes to engine.
usually engine get rough or unstable idle when intake leak occur.
Engine knocking or pinging may feel.

* Whistle when you decrease RPM (engine brake, reduce speed, sometimes just idling but louder when it dropping RPM)
This usually Vacuum-side leak.
There are many vacuum hoses in engine room. even inside of cabin (heater control, etc)
Try to spot where it coming from.
Vacuum also connected to Brake servo, heater control and spark timing.

Put metal or plastic pipe (small PVC pipe will work fine) to one of your ear then isolate source of noise and find where it come from.

heater blows cold air idle chrysler 300 Questions & Answers ...

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Find solutions to your heater blows cold air idle chrysler 300 question. ... blow warmair for a few mins then back to luke warm. i replaced thermostat ... HEAT BLOWSCOLD AIR WHEN IDLING ONLY GETS HOT WHEN START DRIVING ... About 15 minutes after driving the diver side vents start blowing straight cold air but the ...

Heater only works when pressing the gas? - DoItYourself.com ...

www.doityourself.com/...repairs.../459521-heater-only-works-when-pres...

Nov 3, 2011 - When I press the gas, the air from the vents is nice and hot. .... So am Idriving a car with a ton of problems, or could the power steering ... Just anotherquestion, when warmed up does the engine temperature ... When the heater is on and I'm not pressing the gas pedal, luke warm air blows from the vents.

Heater blows cool air when stopped and warm air while ...

https://www.reddit.com/.../heater_blows_cool_air_when_stopped_...

RedditFeb 12, 2014 - Heater blows cool air when stopped and warm air while driving 2008 Kia Spectra (self. ... just fine but appears to blow cool air when I was stopped at a stoplight. ... My temp gauge would also be pegged high when at idle / low RPM. ...thermostat only blocks coolant going to the radiator, and the heater core, ...Missing: 300m ‎luke

Why is My Car AC Blowing Hot Air? - BlueDevil Products

gobdp.com/blog/car-ac-blowing-hot-air/

cold engine idle surge. (problem)
RPM range of surge not stated
300-700 or 800 to 1500? (range is critical to diagnosis)

bad fuel
running summer fuel in winter (running old fuel?)
needs a tune up bad, see the list in the operator guide.
idle speed controller,sticking or EGR valve same. (clean them)
location not stated, so cant guess about local air temps.?
no other symptoms, lack of engine power? etc?
was it ok last week, or better, when was the last time it was OK?
1week, 1year?
surge , causes, on a tuned engine might be:
1: too lean. so lean the ISC can not control idle. rpm low, stalling
2: too rich, flooding, stalling, spark plugs foul (look at them)
3: weak compression in 1 or more cylinders.
4: bad spark.
5: air leaks, in the plenum causing , ISC to lose control.
why high RPM?

especially?
well that means it fails hot too.
and there is a simple tests. for hot surge.
is engine fully hot? 180F and holds solid there?
say rpm is about 800
and you turn on head lights, heater fan and (not AC) and defrost.
the RPM must hold or the ISC is failing.
ISC -= idle speed controls. (all EFI has this function)

Heater core may be clogged. Try flushing it to see if water flows through freely. Also check the heater water control valve for restrictions.

For idle issue,click the help links provided below :---

Bad miss at idle? http://technoanswers.blogspot.com/2012/01/bad-miss-at-idle.html---------- Engine stumbles coming off idle when warm?

http://repairhelpcenter.blogspot.com/2012/01/engine-stumbles-coming-off-idle-when.html

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While stop engine idles like cylinder missing?

http://schematicsdiagram.blogspot.com/2012/01/while-stop-engine-idles-like-cylinder.html

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Idle flair is noticed on car? Rough idle? car will not idle? Erratic idle speed?

http://technoanswers.blogspot.in/2012/02/idle-flair-is-noticed-on-car-rough-idle.html

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High rpm in neutral? Inconsistant high RPM in neutral? http://technoanswers.blogspot.in/2012/02/high-rpm-in-neutral-inconsistant-high.html

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Erratic idle on car?

http://schematicsdiagram.blogspot.com/2011/12/erratic-idle-on-car.html

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Low idle when cold out side?

http://repairhelpcenter.blogspot.com/2011/12/low-idle-when-cold-out-side.html

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Idle Air Control (IAC) Valve Replacing?

http://schematicsdiagram.blogspot.com/2011/12/gmc-idle-air-control-iac-valve.html

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intermittent engine failure while idle?

http://repairhelpcenter.blogspot.com/2011/10/1996-camry-intermittent-engine-failure.html

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Engine quits at idle?

http://repairhelpcenter.blogspot.com/2011/10/engine-quits-at-idle.html

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Car overheats and Air blows hot at idle? http://howtobyme.blogspot.com/2011/11/car-overheats-and-air-blows-hot-at-idle.html

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Car not starting or turning over indicates towards multiple possibilities. It can be issue with battery or weak battery. But if battery checks out ok, then it can be starter issue or faulty alternator or problem with low fuel pressure or no spark at spark plugs due to dirty spark plugs or faulty ignition coil or injectors getting cracked or dirty and needs to be cleaned.

To confirm the problem, the basic troubleshooting is required.

Click this link below and follow the troubleshooting:------

http://technoanswers.blogspot.in/2012/02/car-starting-issues.html

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This will help.

Thanks.

a question to an answer: is your truck has any heat when you rev it 2000 rpm, or above?
have you check your coolant level? if level is low you have a small coolant leak, a water pump may be at fault, and causing air pockets in your heater core, check for leaks your self, dealer wont tell you if vehicle still under warranty.
good luck

hi Planeman.
Why is the heater in my car not working? Ken Mattson, owner of Len's Automotive in Bellevue, Wash., says a car heater can stop working for a number of reasons, including: A low antifreeze/water level in the radiator due to a leak in the cooling system. A bad thermostat that isn't allowing the engine to properly warm up.11 Dec 2013

Why Isn't My Car Heater Working? ' Angie's List

https://www.angieslist.com/articles/why-isnt-my-car-heater-working.htm Search for: Why is the heater in my car not working?
Why is my car heater not blowing hot air?Hot coolant from the engine passes through a heater core, which looks and functions a lot like a small radiator, and a blower motor forces air through it. ... It's also the reason that a plugged heater core, stuck thermostat, or air in the cooling system can all cause a car's heater to blow cold.9 Jul 2017When Your Car Heater Blows Cold Air - Lifewirehttps://www.lifewire.com/when-your-heater-blows-cold-air-534667
How do you fix the heat in your car?Begin with the vehicle on level ground, engine off (cold) in park with the emergency brake set.Heater Controls. Step 1 - A heater cannot operate unless the engine is full of coolant/antifreeze. ...Refilling Cooling System. ...Engine Thermostat. ...Blend Door Actuator. ...Broken Vacuum Line. ...Heater Control Valve. ...Vacuum Gauge. ...Heater Core.How to Fix a Car Heater in Under 30 Minutes - 2CarPros
What are the symptoms of a bad thermostat?A motor with a bad thermostat will run fine for the first few minutes, then overheatrapidly. Other symptoms include the engine and radiator making a rumbling, gurgling, boiling sound: like a steam pipe knock, if you've ever heard one of those. A thermostat sticking open can make your heater not work in the winter.Auto, Car, Truck THERMOSTAT Repair bad thermostat symptoms
or go to this link if you need more help.
2008 ford ranger has heater that won get hot Google Search

Check your coolant level. If it is low, what you describe will happen. Water pump works faster as rpm's increase, managing to get hot coolant to heater core (highway speeds). At idle, pump is not working fast enough to get the coolant to the heater core.

Have you checked the coolant level? What you describe is exactly what happens if the coolant level is low. When stopped at idle, hot coolant is not circulating through the heater core, so no heat. As the engine increases in rpm's when you pull away from the light, the water pump is spinning quicker, and some coolant is making it to the heater core. So check the level, and if it is low, keep an eye on it to see if it drops again. That of course indicates a leak somewhere. Get it fixed, as overheating the engine leads to costly repairs and worse case a new engine. Let me know how you make out with this.

check your coolant level on the radiator