Won’t blow heat on the inside
The heat will not blow on the inside the thermostat has been changed and the heater core has been flushed. What do I need to do?
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
You should start and run engine for at least 5 minutes at 2000 rpms to warm the engine up to full operating temperature. Set heater on medium blower speed and measure vent temperature as temperature is increased with controls. If there is no temperature change at all then the most common cause is the temperature control actuator on the heater a/c temperature blend door. Replace the actuator and check door operation when actuator is off to be replaced. This checks door operation.
How to Identify and Fix Common car Problems ?
Our sources include academic articles, blog posts, and personal essays from experienced mechanics :
Common Car Heater Problems
The heater switching system might be faulty. The cabin air filter might be choked, restricting the airflow through the heater core. The thermostat valve might not be working right. The heater core might be clogged.
The most common reasons a Lincoln MKZ heater isn`t working are a broken heater blower motor, a problem with the thermostat, or a failed heater blower motor resistor. Search our network of RepairPal Certified shops near you to speak with a technician about your issue. Oops! We got lost!
You Don`t Have Enough Coolant If your truck doesn`t have enough coolant, your heating system can`t send it to the heater core. It`s normal for cold air to blow out of your vents for the first few minutes after you turn on the heater. But it should warm up fast. If it doesn`t, your coolant level might be low.
If the engine temperature is warmer then normal but still have no heat. This may be caused by a stuck closed thermostat or other restriction in the cooling system. If this is the case the thermostat will have to be replaced. This can lead to engine damage if left alone.
If your coolant level is a-okay, but your car heater is blowing cold air and your engine is overheating, then you have a clog in your cooling system. Conversely, if your engine temperatures are unrealistically low after a drive, your thermostat is likely the culprit.
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.
The lukewarm air appearing in your heater can be the outcome of a leaky duct. If your air ducts are leaking, cool outside air is making its way into your ductwork. This can cause the air to really feel only lukewarm. The repair: Duct sealing.
The most common reasons a Ford F-150 heater isn`t working are a broken heater blower motor, a problem with the thermostat, or a failed heater blower motor resistor.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
A/C and heat are not working properly. Car blows heat in summer and cool air in winter.
ANSWER : Common causes of no cabin heat include malfunctioning blend door(s) (part of the in-dash ventilation network), a faulty or stuck heater control valve, a plugged heater core, stuck open engine cooling thermostat, collapsed hoses, and low coolant level. The cost to resolve the problem depends on which of the foregoing faults is the cause. If you desire a diagnostic to determine exactly why there is no cabin heat, please request a non functioning cabin heater diagnostic and the responding mechanic will come right to your location and get this resolved for you promptly.
With regard to your air conditioning system, if merely re-charging the system restored normal operation but the a/c ceased to function after a month or so, that scenario typically suggests a leak. Some leaks are really cheap to repair, like if a couple o-rings need to be replaced in system piping but if the leak is at the compressor shaft seal, that repair is more costly. It is not expensive to find the leak and diagnose the system and once the leak is found the mechanic can let you know of the exact cost to repair the leak and re-charge the system. If you desire that service please request an a/c system diagnostic – suspected refrigerant leak and the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you
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.
My heat and air turns on without a problem but does not blow very hard (heat blows harder than air). Rattling noise.
ANSWER : The heater and the air conditioner both use the same blower motor. However, Nissan does have two separate fuses for the same unit. One of them can be blown. There are also resistors in the system that can fail. There are several electrical tests that can be done, but depending on the condition, it may be more practice to change the entire unit. Due to the age of your vehicle, and the Juke’s history of blower motor issues, it’s very likely a simple fuse issue. These can (for the most part) be visually inspected, and are cheap.
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.
Car won’t drive after over heating on the highway
ANSWER : Hi there. Most of the time when you overheat this engine it will also cause the transmission to get too hot. When this occurs it can easily cause transmission failure. I would suspect this if the vehicle does not move at all. If it move but is severely lacking power then you either have some serious internal engine damage or a failure in the catalytic converter from the overheating. It sounds like it is the transmission though. I would recommend having a transmission specialist take a look at it.
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.
No heat, antifreeze leak, overheating engine
ANSWER : Hi…stop leak products should never be introduced into a car engine’s cooling system simply because such aftermarket products are not a factory authorized or factory sanctioned repair technique. Some factory service manuals are indeed emphatic on this issue. A stop leak product is, in essence, a foreign contaminant and thus has the potential to plug up cooling passageways, the radiator and so forth. The only recognized technique employed by professional mechanics when it comes to a leak in the cooling system is to repair the leak, period. At this point, by far the cheapest and most effective strategy for you will be to have a mechanic identify the leak(s) (via pressure testing, if need be, on a cold engine), repair the leak, and thoroughly flush the cooling system to hopefully remove all traces of the stop leak product. The cooling system has to then be refilled with new coolant, while purging all air, and tested. On a vehicle with over 200,000 miles, it is possible the leak occurred along with other cooling system faults such as a failing thermostat, water pump, and possibly partly clogged passageways, particularly in the radiator. All of that will have to be evaluated to ensure that no further overheating occurs. To get this resolved promptly and professionally, by all means please feel free to request a leak diagnostic and the responding certified mechanic will get you squared away. If you have additional concerns or questions, please do not hesitate to contact us.
