Heat inside car stays warm for minute then blows cold until I turn heat off for a minute and try again.
Hello, I own a 2002 Mercury sable 3.0 OHV, 125,000 miles. I just found out the heat on my car hasn't been working and it's hard to pinpoint the exact time this started because it has been summer months and just recently I've needed to use my heat. The car will heat up to normal operating temperature on the gauge and nothing out of the ordinary and I'll turn the heat on and after waiting the normal couple minutes while driving I notice the heat isn't all too warm, so I'll turn off the heat and drive a little more and then turn it on and it'll be nice and warm and p
Experienced mechanics share their insights in answering this question :
Hi there. The engine always at operating temperature leads me to believe, the thermostat is not the cause, for no heat inside the vehicle. There are several possibilities for no heat inside, the heater control valve is malfunctioning, the heater core is restricted, the temperature blend door actuator is malfunctioning. Replacing components without diagnoses, can be expensive and time consuming without resolution. I recommend having your vehicle’s inoperative heater be diagnosed and repaired by a certified technician, such as one from YourMechanic.
How to Identify and Fix Common car Problems ?
Our sources include academic articles, blog posts, and personal essays from experienced mechanics :
The most common cause of a furnace that blows cold and warm air intermittently is a thermostat fan setting that is set to ON. Furnaces run in heating cycles and only produce hot air for short bursts of time. When your fan setting on your thermostat is set to AUTO, the fan only blows when the furnace is heating the air.
Low Coolant Level If there isn`t enough coolant in your system, the heater core will blow cold air into your car. Solution: If you confirm that a low coolant level is the source of your problem, you simply need to top off your coolant. You may want to check for leaks as well if you just recently refilled your coolant.
A faulty or broken thermostat is the most common cause of your car`s failing heat. Stuck open or stuck closed, the part can not only cause issues with your heat but also with your engine`s cooling system. One becomes an issue of comfort, the other becomes an issue of “Oh no, I`ve borked my engine.”
Your Coolant System May Be Airlocked If your heat only works when driving, this can also be caused by air pockets. Air pockets within the cooling system can prevent adequate coolant circulation and are sometimes the result of low coolant or a faulty radiator cap.
Hot air rises, because it`s less dense than cold air. Warm air in a room quickly rises upward, and cold air sinks downward, even if the tempera- ture differences are quite small.
A few things that cause automotive heaters to work less well are low coolant levels in the radiator, a faulty heater valve, or the thermostat is stuck open. Have a certified mechanic replace your thermostat if necessary or diagnose and repair other cooling system issues, such as leaking coolant.
If your furnace keeps turning off before reaching the intended temperature, the culprits are likely rust and corrosion. Rust is a result of invasive water damage like corrosion, humidity, or leaks in your furnace system.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
Heat inside car stays warm for minute then blows cold until I turn heat off for a minute and try again.
ANSWER : Hi there. The engine always at operating temperature leads me to believe, the thermostat is not the cause, for no heat inside the vehicle. There are several possibilities for no heat inside, the heater control valve is malfunctioning, the heater core is restricted, the temperature blend door actuator is malfunctioning. Replacing components without diagnoses, can be expensive and time consuming without resolution. I recommend having your vehicle’s inoperative heater be diagnosed and repaired by a certified technician, such as one from YourMechanic.
everytime I turn my car on the ac starts to blow air even if I switch it off. it won’t blow cold air or heat.
ANSWER : Hi there. Based on your question and input, it looks like your AC control switches are damaged, causing the vents to activate even if the switch is not activated. This is sometimes an electrical problem, as it could be triggered by a damaged electrical relay. You might want to have a professional mechanic complete an AC is not working inspection, so they can determine what is causing this issue you’re experiencing and recommend the right repair.
When I turn on my AC the radiator fans do not turn on. The fans do come on when the car warms up so I know they are working and the fuses are good. The AC compressor does come on and the air blows ice cold when the car is moving. Car is a 2006 Chrysler Sebring Sedan 2.7l v6.
ANSWER : The control circuit for the fans needs to be checked. For example, there is usually a condenser fan relay in the A/C electrical controls. There could be a fault with that relay and/or wiring problems, perhaps even just a loose connection, blown or loose fuse, and so forth. To resolve something like this, the recommended service is an electrical component diagnostic. If you request that diagnostic service, the responding certified mechanic will get the problem pinpointed and resolved. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
Engine turned off but inside of car still on, now engine won’t turn back on.
ANSWER : Hi there. The symptoms you’re describing with your boyfriend’s 2002 Grand Cherokee appear to be related to a broken or worn out ignition switch or relay. The ignition switch on the inside of the steering column is attached to multiple electronic connections that send signals to a relay box; which in turn, sends the signal to the individual components. The issue could be related to the ignition switch, the relay, or any of the components in between. If you want to have the fault pinpointed in person, I would have this starting issue inspected by a trained professional to ensure that the correct repair is made.
Overheats When Blowing Warm With Heat & AC But Not When Blowing Cold AC
ANSWER : Hello, thank you for writing in. There are so many different codes being triggered, that it is unlikely all of these systems are having issues at once. We need to focus in on the fact the engine is overheating at all. You will want to check the level and condition of the coolant and the overflow tank. If the level is full then you may have an issue with the thermostat, radiator cap, or water pump. These can all be tested and changed relatively easily. If the main cooling system is okay, you will want to look into the heater core and climate control module. For more diagnostic help, contact our service department to schedule an appointment.
Car will blow cold air but will not blow heat
ANSWER : The heater not working in some cases may be related to the overheating problem you are also having. This may be due to a faulty heater blower motor or potentially a bad heater core. As you may know, the heater core is a small radiator like unit that circulates the hot coolant from the engine through the heater core which then uses this warm coolant to heat the inside of the car with the help of the blower motor that blows the warm air through the vents inside the car. When the cooling system is not properly circulating coolant through the motor, this results in the warm coolant not being pumped through the heater core properly in order to warm the inside of the vehicle.
Engine overheating can be caused by a number of things such as low coolant levels, a faulty thermostat, or a failing coolant fan switch. As you may know the coolant fan switch helps to maintain the proper coolant temperature by turning on and off at specific temperature thresholds. When this switch is not working properly, this can cause the fans to come on intermittently, all the time or sometimes not at all. When this happens you will notice a temperature spike and drop occasionally as the fan comes on and off. When your thermostat is not working properly or is stuck closed, this will not allow the coolant to properly circulate through the engine, which may cause the engine temperature to fluctuate erratically or in some cases just remain hot. As mentioned above, this also restricts the warm coolant from flowing through the heater core which uses this to blow warm air into the cab of the vehicle. I would suggest having an expert from Your Mechanic come to your home to diagnose your cooling system.
Car was overheating almost to the red. I turned heater on, first it blew cold air then warm air for just a minute, then cold air.
ANSWER : Hi There,
The heater not working may be related to the overheating problem you are also having due to a faulty heater blower motor or potentially a bad heater core. As you may know, the heater core is a small radiator like unit that circulates the hot coolant from the engine through the heater core which then uses this warm coolant to heat the inside of the car with the help of the blower motor that blows the warm air through the vents inside the car. When the cooling system is not properly circulating coolant through the motor, this results in the warm coolant not being pumped through the heater core properly in order to warm the inside of the vehicle. In some cases there may be air pockets in the heater core which can cause the heating of the inside of the vehicle to fluctuate between warm and cool air erratically.
Engine overheating can be caused by a number of things such as low coolant levels, a faulty thermostat, or a failing coolant fan switch. As you may know the coolant fan switch helps to maintain the proper coolant temperature by turning on and off at specific temperature thresholds. When this switch is not working properly, this can cause the fans to come on intermittently, all the time or sometimes not at all. When this happens you will notice a temperature spike and drop occasionally as the fan comes on and off. When your thermostat is not working properly or is stuck closed, this will not allow the coolant to properly circulate through the engine, which may cause the engine temperature to fluctuate erratically or in some cases just remain hot. As mentioned above, this also restricts the warm coolant from flowing through the heater core which uses this to blow warm air into the cab of the vehicle. I would suggest having an expert from Your Mechanic come to your home to diagnose your cooling system.
As I’m driving, all my lights inside/out of the car turn off and the car still stays on. But when I turn the car off it won’t turn over
ANSWER : Hello there. The charging system on the car may not be charging the battery as you drive and the systems that keep the engine running are priority so the engine will stay running until the voltage drops below about 9 volts but the lighting and some other accessories may cut off above this voltage first. You should have the charging system tested to see if the alternator needs to be replaced.
