the cabin department. Why?
My heater seems to blow hotter when I’m driving versus when it’s sitting at idle or at a stop light. Also the heater takes too long to heat up the cabin department. Why?

When heating my car up in the mornings the heater doesn't get to it's full warmth until I start driving. Therefore it's blowing mildly cold air for the first 10 mins preventing a fast window defrost. I've made sure the coolant (50/50 mix) is filled to the line. First time experiencing this.

My car has 90000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
Hi there. When your vehicle is in motion and driving down the road, then engine coolant temperature tends to get hotter on the engine before it gets to the radiator, so the heater will naturally heat up more when driving around. As far as the heater not heating up fast in the car, either the engine coolant is not hot enough yet to heat up the car or there is an issue with the heating system or cooling system in the vehicle. First check the engine coolant to make sure that its full. Top off the coolant if its low. Then check the heater control valve and see if its opening up when the temperature is at operating temperature. If the valve is not opening up, check the vacuum hose to it for any leaks. If nothing is found on the valve, then the valve needs replaced. If the valve is working correctly, then the thermostat may be sticking open when the engine coolant is cold.

The thermostat’s job is to bring the engine to operating temperature in a timely manner. If the thermostat is sticking open, then the engine not only will have a longer time to warm up the coolant, but the computer system will think that the engine is cold all the time and make the fuel system go full rich all the time. This will give the vehicle a poor fuel mileage and a waiting time for the heater. In this case, the thermostat would need replaced. If you need further assistance with your vehicle, then seek out a professional, such as one from YourMechanic, to help you with your heater not heating up in a timely manner.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

You may have trapped air in the cooling system or the heater core may be partially plugged up. Engine coolant is delivered to the heater core through two heater hoses.
Your engine accumulates a lot of heat when working, and coolant helps to collect this generated heat by transporting it to your vehicle`s radiator for cooling. If the coolant is low and your heater is on, you may notice that your car heater only works when driving.
Clean Filters

One of the most common issues with a heating system not functioning is dirty air filters. If your air filters are extremely dirty, then the airflow can be blocked. Check for clean air filters, vents, and registers. Make sure there are no rugs or furniture blocking vents or registers as well.

This problem could be either an engine thermostat that is not keeping the engine at a constant running temperature (temp gauge steady in the center), or the heater control valve or controls are malfunctioning not allowing engine coolant into the heater core (passenger compartment).
Two things come to mind, defective or wrong thermostat or low coolant level. The engine makes very little heat when idling, and if the thermostat does not close, the engine coolant temperature may drop low enough that you`ll get no heat from the heater core.
If your furnace is blowing cold air in your home, this is a sign of an issue with the flame detector, gas supply, air filter, pilot light, or condensate lines. Many of these issues are able to be easily solved on your own by sanitizing or replacing components in the gas furnace.
The heater control valve (sometimes called the hot water valve) is used to control the rate at which coolant flows through the heater core. The valve is located on the heater inlet hose. Manually operated systems may use a cable, a vacuum motor or an electric solenoid to operate the valve.
If your furnace shuts down after a few minutes, it`s likely due to a faulty or unhygienic flame sensor. This crucial component intends to monitor the gas burner. Also, when a flame sensor cannot detect the burner, the furnace runs for a few moments before shutting down and restarting.
A faulty thermostat can cause your heating unit to run and not turn off. The unit may have a broken heating sensor, the wiring may have gone bad, or the switch itself may have broken. The older the thermostat is, the more at risk you are for this happening. Fortunately, a broken thermostat is an extremely easy fix.
Here are the most common reasons why your car heater isn`t blowing hot air. Low coolant: Whether caused by a leak or water evaporation, low coolant is the most common source of poor heater output. Thermostat: A stuck-open thermostat prevents the engine (and coolant) from heating up.
Across almost all models of cars and trucks, the number one cause for a vehicle`s heater to stop working is a faulty or broken thermostat.
Dirty or low engine coolant can make it so your car heater works only periodically. If you`re experiencing on-again, off-again performance from your heater, this could be a sign you need to have your engine coolant inspected.
It`s most likely an incorrect thermostat setting if you find your furnace blowing warm air, not hot. The fan is set to “on” instead of “auto.” Furnaces only pump hot air until the thermostat setting is reached, so if your fan is always on, it will blow both hot air when the furnace is heating and cold when it`s not.
“Aux” is short for auxiliary heat. If a heat pump is having a difficult time coming up to a certain temperature quickly due to extremely cold outdoor temperatures, the “aux heat” indicator means that a secondary heat source (generally gas or electric) has been deployed.
Airflow Problems

Dirty air filters restrict airflow, which can make it feel like not much heated air is coming out of your vents. Check the furnace filter and replace it if its surface is covered with contaminants. Change the furnace filter on a regular basis to prevent airflow problems.

Faulty Thermostat

The thermostat is a device that regulates coolant flow to the engine. If the thermostat is damaged, it can cause the engine to overheat while idling. This is because the coolant is not flowing properly and cannot dissipate the heat properly.

Revving your engine will not make it warm up any faster, but it will subject your engine to increased stress before the oil has had the chance to circulate properly. You should also avoid accelerating too quickly until the engine has fully warmed up.
A heater core can be flushed with just water (and will need to be flushed with water either way), but using an air compressor tends to be better at breaking up hard to remove clogs. As the air compressor builds up pressure in the heater core, it will move the grime and coolant out of the inlet hose, into the container.
A faulty heater control valve may not be able to properly control coolant flow to the heater, which may result in problems with operating the heater. The heater may produce hot air, but only at certain times, such as at idle, and the hot air may come and go.
Common signs include inconsistent cooling, out-of-date software, and uneven air distribution, since the module controls the whole AC system.
Heater control valve bypass is not standard on vehicles; it is a modification. When bypass hoses are installed, the coolant in your car will always be circulating through the heater core – that means that if the core starts leaking, you won`t be able to turn it off.
Standard thermostats: Enlist a friend or family member to assist, Position one person by the thermostat and one person by the furnace. Slowly turn the thermostat from off to heat and increase the temperature. Both the thermostat and furnace should make a sound.
If your furnace is not turning on you should first check if the filter is clean. Dirty filters cause insufficient airflow and can prevent the furnace from starting. Other reasons it won`t start can stem from improper thermostat settings, forgetting to turn on the gas line, or faulty pilot light.
So, if your furnace keeps turning off and on too quickly, your thermostat might be malfunctioning or broken. There are several things that could be causing your thermostat to not work properly. The wiring could be old and need replacing, it might need new batteries, or it could be the location of your thermostat.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

My heater seems to blow hotter when I’m driving versus when it’s sitting at idle or at a stop light. Also the heater takes too long to heat up the cabin department. Why?
ANSWER : Hi there. When your vehicle is in motion and driving down the road, then engine coolant temperature tends to get hotter on the engine before it gets to the radiator, so the heater will naturally heat up more when driving around. As far as the heater not heating up fast in the car, either the engine coolant is not hot enough yet to heat up the car or there is an issue with the heating system or cooling system in the vehicle. First check the engine coolant to make sure that its full. Top off the coolant if its low. Then check the heater control valve and see if its opening up when the temperature is at operating temperature. If the valve is not opening up, check the vacuum hose to it for any leaks. If nothing is found on the valve, then the valve needs replaced. If the valve is working correctly, then the thermostat may be sticking open when the engine coolant is cold.

The thermostat’s job is to bring the engine to operating temperature in a timely manner. If the thermostat is sticking open, then the engine not only will have a longer time to warm up the coolant, but the computer system will think that the engine is cold all the time and make the fuel system go full rich all the time. This will give the vehicle a poor fuel mileage and a waiting time for the heater. In this case, the thermostat would need replaced. If you need further assistance with your vehicle, then seek out a professional, such as one from YourMechanic, to help you with your heater not heating up in a timely manner.

I have 97 nissan altima, It stalls when I stop at stop lights and idle, the RPM vibrates and falls down and the lights come on, it
ANSWER : Hi there. Usually when you have a problem like this, it is caused by fuel system components that are clogged with excessive carbon build-up or deposits. This creates a restriction in the efficient flow of fuel and can cause the vehicle to stall. It’s also possible that emissions system components like EGR valve, mass air flow sensors or O2 sensors are faulty. I would recommend having a professional mechanic come to your location and complete a car starts the dies inspection, so they can pinpoint the source of your issues and recommend the right repairs.

My vehicle occasionally heats up and blows cold air out of the heater vents.
ANSWER : If you are getting the heater to work sometimes and other times not then it is due to the engine cooling system has air in it. You should have the cooling system purged of air and then retest system. As long as the engine is full and good flow of coolant through the heater core then you will have heat.

Low coolant light comes on when AC, defrost or heater is on, but only if the car is in gear and stopped, what’s wrong with my car?
ANSWER : First, you want to make sure your cooling system is full. Check the radiator not the coolant jug. And check it when it is cold. If it needs coolant, add some. Of course, I don’t feel this problem is an actual low coolant condition. I would expect to find an electrical failure in the instrument cluster or from a component or wiring harness that is connected to the instrument cluster.

As a technician, I have access to reports from technicians across the country. I could not find any reports of this problem, so diagnosing this will require an experienced tech as this is not a common problem. In addition, this happens at intermittent times making it difficult to recreate. The most challenging part of this diagnosis will be recreating the symptom. I suspect it has something to do with the brake switch circuitry because it only seems to happen when you have your foot on the brake. I would begin my diagnosis there with a wiring diagram and test light in hand. The brake switch, instrument cluster, and environmental controls all interact with each other. Something is crossed either because of a failed module or damaged wiring in a harness.

Aside from making sure the coolant is full, this will not likely leave you on the side of the road. If you take it in to be diagnosed, be prepared for them to spend more time than usual to figure it out. Since it isn’t a key problem, you may need to live with it until it completely fails making it much easier to diagnose. Either way, I do recommend having a certified mechanic diagnose the warning light to make sure there isn’t anything serious going on.

Good luck.

Check engine light is on and the car does not want to drive
ANSWER : Hi there:

On most modern cars, there are a series of sensors that are designed to monitor mechanical systems; such as the transmission on your Saturn. In most cases, when a problem occurs, a trouble code is stored in the on board computer that will indicate what is causing the troubles. The best way to find out what’s going on is to not take your car to a shop; let the mechanic come to you. Contact one of our professional mobile mechanics to complete a check engine light inspection first. This will allow them diagnose what’s wrong with your car so they can recommend and complete the right repairs.

Why does my brake warning light go on (for long period of time) and off (also for long period of time) while driving?
ANSWER : Hi there. The brake system Warning Light can illuminate for two reasons: First, the parking brake is currently engaged. Second, a component within the the brake system is malfunctioning. If the brake system Warning Light is illuminated, and the parking brake is released, then there is most likely an issue with the brake system, and the vehicle should be inspected as soon as possible. It’s probably a good idea to have a brake warning light inspection completed by a professional mobile mechanic so they can determine what’s causing these issues.

only heast when driving cold when idle. heating core flushed twice. heat control valve and blend door seem to be working
ANSWER : The normal operating temperature for most automobile engines, including yours of course, is in a range of 185 to 220 degrees Fahrenheit. If your dash gauge is reporting a temperature as low as 140 degrees F, that likely means the car’s cooling system thermostat is stuck in the wide open position, thus preventing the engine from maintaining the desired temperature range. Not only will such cause very low temperature cabin heat but your fuel economy will be lower as well because the engine operates less efficiently if outside the design temperature range. As far as heater cores and radiators, if they are truly plugged, flushing is effective to varying degrees but, of course, just because you go through the "exercise" of flushing doesn’t mean the flushing has succeeded. Technically, you can flow test these parts after you have attempted to unplug them, but it is often more cost effective and more reliable to just simply change out the "damaged" component. Once a radiator is plugged up, it is usually has other problems as well. In fact, if you are really successful in flushing a radiator, you may dislodge the contaminants that are preventing it from leaking. At any rate, in your circumstance the best thing for you is to schedule a thermostat inspection/replacement during which the responding certified mechanic will go over everything and be sure that you do not have additional issues that are a cause of the no heat condition.

2007 Honda Pilot Check Engine Light and VSA light on and idling at higher RPM, problem with acceleration
ANSWER : Hi there. The Vehicle Stability Assist light typically will trigger when the system has been disabled and it not the source of misfiring or acceleration issues in most cases. Since your check engine light is illuminated as well, it is highly probably that the root source of this issue will be discovered by having a professional mobile mechanic complete a check engine light inspection. This will permit them to download all stored error codes and correctly diagnose the root issues your Honda Pilot is experiencing and recommend the right repairs.