Temperature gauge goes to high when car is stopped

ANSWER : To begin, this isn’t something an inspection would reveal unless the mechanic was specifically looking for it.

Firstly, how high does the temperature gauge rise when you come to a stop? It is normal for this to occur, especially in warmer climates such as Arizona or Nevada. If it continues to rise into the red, then it is definitely a problem however.

The next possibility has to do with air flow through the fins of the radiator. Look through the fins of the radiator from the front of the car. It should be clear of all debris. This includes the condenser that maybe mounted in front of the radiator. If the radiator and condenser are clear of debris, and the cooling fan is pulling air through the radiator, the next thing to question is the clogging of the radiator. This can be checked by warming the vehicle up until the thermostat is open, driving the vehicle for a few blocks to get some air flowing through it, stop, turn the motor off and feel the radiator with your hand. Be careful the cooling fan doesn’t turn on. Honda’s will often turn on with the key off. You are feeling for cold spots in the radiator. They will be obvious. But keep in mind, the coolant enters from the top and exits out the bottom radiator hose, so the bottom of the radiator will be colder than the top indicating the radiator is doing what it should. If there are cold spots that are obvious, then the radiator is clogged internally. This is a very common symptom for Honda’s.

What happens when the A/C is on, is the condenser gets hot and adds more heat for the radiator to dissipate. If the radiator is clogged internally, it is unable to adequately cool at a stop because there isn’t enough air flowing through the fins. Without the A/C on, the condenser doesn’t get hot and the radiator has enough cooling capacity to do its job.

I would also recommend a thermostat and keep in mind, it often takes some experience with checking for cold spots in the radiator to identify them. So if you are uncertain, book one of our technicians to help your out with the diagnosis of you overheating issue. Once the fault has been pinpointed the mechanic can then perform the repair that is necessary.

Good luck.

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.

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.

ANSWER : Hi there, thanks for writing in. The Toyota maintenance light is a reminder to get your oil changed. This light comes on periodically and needs to be reset with every oil change. As for the temperature gauge this is normal. The engine is cold when it is first started so it reads like this and as it runs it warms up and the gauge starts moving. This is normal. I would just have your oil change done when you get a chance. If you want to have your oil changed, consider YourMechanic, as a certified mechanic can come to your home or office to do this.

ANSWER : It sounds like you may have a dirty or failing idle air control valve. The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. This valve is controlled by the vehicle’s computer and will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. This is also an important function when starting the motor as it allows the motor to run and idle on it’s own once the motor fires. When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed with the help of the idle air control valve making the transition from a higher RPM back down to idle speed while adjusting the air/fuel ratio constantly to allow this to happen smoothly. When the engine RPM drops below the normal range of about ~800 RPM, this often times will cause the engine to stall indicating a dirty or faulty idle air control valve. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.

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.

ANSWER : The condition of your car’s cooling system was probably "marginal" prior to the a/c repair and what has happened is the additional engine load that a/c operation is now creating has "tipped the scales" and so you now see the overheating. Be sure not to operate the car if it is actively overheating because overheating can warp the cylinder head and/or engine block causing costly damage. The most common causes of overheating include low coolant level (including that due to leaks), a faulty thermostat, a plugged radiator, a faulty radiator pressure cap, collapsed hoses, non functioning cooling fans, and a faulty water pump or drive belt. Certain engine faults, such as a leaking head gasket or poor engine running condition (lean operation, exhaust blockages and so forth) can also cause overheating. If you desire that this problem be diagnosed by a certified Mechanic, dispatched by YourMechanic right to your location, please request an engine overheating diagnostic and the responding certified mechanic will 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.

ANSWER : What you are describing sounds like a dirty or failing idle air control valve. The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. This valve is controlled by the vehicle’s computer and will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. This is also an important function when starting the motor as it allows the motor to run and idle on it’s own once the motor fires. When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed with the help of the idle air control valve making the transition from a higher RPM back down to idle speed while adjusting the air/fuel ratio constantly to allow this to happen smoothly. When the engine RPM drops below the normal range of about 800 RPM, this often times will cause the engine to stall indicating a dirty or faulty idle air control valve. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.