No heat and the temperature gauge goes down.

I changed the thermostat changed the heat sensor and changed water pump and the car still has no,heat unless it sits but as soon as you start driving the temperature Guage goes back down and car starts to get cold again please tell me what could this be
Experienced mechanics share their insights in answering this question :
Hi there. Check the heater control valve on the heater hoses under the hood. The valve is controlled by vacuum. Check the vacuum lines and see if they have came off or split. With the engine at operating temperature, check the heater hoses before the valve and after the valve. The hoses should be the same temperature with the heater on. If the hoses after the valve are not as hot as the hoses before the valve, then the heater control valve is not working and needs replaced. If the valve is replaced and the heater still is cold, then check the thermostat switch for any loose contacts or damage. If you need further assistance with your heater being cold, then seek out a professional, such as one from Your Mechanic, to help you.

How to Identify and Fix Common car Problems ?

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

Check the Coolant and Water Pump

First, check your coolant level to be sure there is enough liquid in there to even get to your heater core. If your radiator is very low on coolant, you`ll get no heat. If your levels are okay, you either have a bad water pump or a thermostat that isn`t opening.

Low coolant may prevent any from circulating through the heater core, as can an air bubble in the system. Make sure the system is full and free from air by filling it with the engine running and the heater controls set to maximum heat.
The most common reasons a Chevrolet Camaro 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!
You May Have Low Coolant

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.

A malfunctioning thermostat can make your heater or air conditioner unable to turn on. In most cases, this indicates the wiring has failed. Normally, electrical wires transmit messages from the thermostat to the HVAC unit, such as telling it when to turn on and what temperature to make your house feel.
Faulty Thermostat

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.

The average cost for a Chevrolet Camaro Heater Core Replacement is between $908 and $1,139. Labor costs are estimated between $747 and $942 while parts are priced between $161 and $197.
The heater core in your car works like a radiator to move hot air through your car`s vents. Damage to your heater core will have some telltale signs. Excessive condensation on the inside of your windows tends to indicate a leak. Your heater will also only give off lukewarm or cold air if your core has a problem.
Start your car`s engine and allow it to idle. Look through the radiator filler neck to see if the coolant flows. At this time, it should not be flowing as your car has not reached the operating temperature to cause the thermostat to open. If you find the coolant is flowing, it means the thermostat valve is open.
To do so, locate your home`s thermostat and tape an accurate thermometer on the wall next to it. Wait 15 minutes and check the temperature reading on both devices. If your readings are three or fewer degrees apart, you should be good to go.
Heater Core Gurgling Noise

Can you hear a gurgling noise coming from the heater core? This usually means that there is air trapped in the coolant that circulates through the core. This can happen for a number of reasons, including a blown head gasket or a leak developing in the heater control valve.

There are multiple reasons a car`s heater core could not be working properly. One reason could be due to clogging, as the coolant could become contaminated if it`s not regularly flushed out. Another reason for a bad heater core could be because of a leak somewhere in the system.
To get there as quickly as possible, the thermostat closes to keep the coolant inside the engine from travelling through the entire cooling system. Once the engine warms up enough, the thermostat opens. That now-warm coolant circulates into the heater core to keep you toasty.
You Have Cold Air Blowing Out The Vents When The Heat Is On Because of a Dirty Air Filter. Hiding in the filter of your heating system is dirt and debris. If you aren`t cleaning it regularly, this will accumulate over time, leading to problems with your heating system`s efficiency.
Water by itself can`t do the job of antifreeze due to its lack of boiling and freezing point range and its inability to protect your vehicle`s engine. Plus, it doesn`t absorb heat as effectively. In the case of an absolute emergency, you can use water in your coolant rank.
When there is a leak in the cooling system, it allows air into the system causing an airlock. The airlock blocks the coolant from circulating through the system, potentially causing the vehicle to overheat.
The warmth from the engine goes from the radiator to the heater core, which basically acts as a heat exchanger. It allows coolant to flow through, and this flow of coolant is regulated by the heater control valve. As the engine`s heat is carried by coolant into the heater core, the device starts to get warm.
Yes, many air conditioners can be used for heating as well as cooling, with the inclusion of a reversing valve. The energy flow can be reversed which transforms the air conditioner into a heater. This is called reverse-cycle technology.
How Frequently Does a Chevrolet Camaro require maintenance? Overall – the Chevrolet Camaro has yearly car maintenance costs total to $585 .
Fixing a leaking heater core will always be much easier than replacing one. Since it is only a small leak in the heater core, we recommend simply sealing that leak and leaving your heater core in place. You can do this by simply by adding BlueDevil Pour-N-Go to your vehicle`s radiator when your vehicle is cold.
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.
Low Coolant Level

The coolant (usually a mixture of water and antifreeze) in your engine doesn`t just work to keep the engine from overheating: It`s also the source of heat supporting the heating system. If there isn`t enough coolant in your system, the heater core will blow cold air into your car.

Adding coolant does nothing to address the problem that caused your engine to overheat in the first place, but it often allows you to drive safely to the nearest repair station. “A professional will need to inspect your car`s cooling system,” says Reina. While driving, keep an eye on the temperature gauge.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

When heat is on temperature gauge goes towards cold. When heat is off it goes back to being in the middle. 2001 Buick Regal
ANSWER : Hi there – the temperature gauge behavior you describe would indicate that you need a new thermostat. The thermostat should keep engine temperature within a close range – close to the center of the gauge from a visual point of view. The fact that turning on the heater allows the engine to cool down indicates that the thermostat is not doing it’s job. It’s impossible to know what the service center put in your cooling system prior, but you are correct – Dexcool, the GM-recommended coolant, has an orange tint to it, and should be used in your engine. I would recommend having your thermostat replaced by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, replace your thermostat, refill your cooling system, and bleed it. Your temperature gauge should remain centered from then on, and you can be sure the correct coolant will then be in your engine.

i have an infinity g37s.. sometimes when the car is at idle temperature gauge goes up but i drive goes to normal fans r workink
ANSWER : The gauge read temperature may fluctuate to a limited extent. However, on most gauges, if the pointer is past the centerline of the gauge, that suggests a problem. Generally, the engine temperature should read below 210 degrees or so. If you are above that at idle, there is a possibility that the thermostat is sticking but other faults can cause elevated temperature at idle. The principal reason the temperature drops when moving is that higher airflow through the radiator dissipates more heat, thus tending to mask any cooling system fault, if there is even a fault. If you suspect above normal operating temperature, your best bet is to just schedule an overheating diagnostic and if there is a fault, the mechanic will pinpoint it and get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

I have a problem with the temperature gauge – 2002 Buick Rendezvous
ANSWER : Hello. The temperature gauge is going to elevate based on the resistance of the sensor. The first thing to check is the temperature sending unit. The wires or the sensor itself may be corroded or damaged. This would cause extra resistance in the system and cause the gauge to be off.

You can test the readings coming from the temperature sensor. You will want to test for resistance and match it to the correlated temperature. You can find these specifications based on make and model. This would inform you of what the gauge thinks the temperature is versus what the scanner is reading. If they are off, then you know the sensor is bad and you should replace it. The sensor will signal the computer as to when the fans should be turning on. If the fans are not turning on soon enough, this would be the cause.

I recommend having a certified mechanic, such as one from YourMechanic, come to your location to determine if the gauge is faulty and replace the temperature sending unit if necessary.

No heat and the temperature gauge goes down.
ANSWER : Hi there. Check the heater control valve on the heater hoses under the hood. The valve is controlled by vacuum. Check the vacuum lines and see if they have came off or split. With the engine at operating temperature, check the heater hoses before the valve and after the valve. The hoses should be the same temperature with the heater on. If the hoses after the valve are not as hot as the hoses before the valve, then the heater control valve is not working and needs replaced. If the valve is replaced and the heater still is cold, then check the thermostat switch for any loose contacts or damage. If you need further assistance with your heater being cold, then seek out a professional, such as one from Your Mechanic, to help you.

My temperature gauge goes to hot while idling, but the car does not overheat.
ANSWER : The rise in temperature is due to the fan clutch not engaging the fan clutch until the temperature gets too high. This is the first indication that the cooling fan clutch is going bad. If you replace the cooling fan clutch using the correct one for your vehicle, it should fix the temperature problem.

I recommend having a certified mechanic, such as one from YourMechanic, come to your location to determine why the car is running hot and suggest any needed repairs.

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.

Heating unit makes my temperature gauge go up
ANSWER : Hi there. It sounds like there could be the possibility of a low cooling system level. Check the level when the engine is cold and add as necessary. When you turn the climate controls to heat the inside of the car, coolant is diverted to the heater core to use the heat in the coolant to warm the air as it passes over. If this is producing an unusually low level in the cooling system, the coolant temperature sensor may act erratic as it would trying to measure temperature of a limited supply of coolant. Note that air heats faster than water and the sensor could be reading the air in the system.

I strongly suggest acquiring a qualified technician to perform an inspection and avoid replacing unnecessary parts. YourMechanic has several technicians available that can assist you with a cooling system inspection and provide an estimate and direction of repair.

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