Over heating

My car heating guage shows that its heated when car is in low speed.
When car is in speed it become cooled

My car has 100000 miles.
My car has a manual transmission.

Experienced mechanics share their insights in answering this question :
This 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. I would suggest having an expert from Your Mechanic come to your home to diagnose your cooling system.

How to Identify and Fix Common car Problems ?

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

Why does my Suzuki`s engine overheat? There are two main causes for engine overheat: The coolant does not flow through the system like it should. There is not enough air flowing through the radiator.
Low coolant: Although said above, it is worth reiterating: Your engine relies on coolant to dissipate heat. If you don`t have enough coolant running through the system due to leaks, ruptured hoses, loose hose clamps, whatever heat will build up, and your engine will overheat.
There are a variety of reasons that a vehicle can overheat, such as cooling system leaks, blocked hoses from corrosion and mineral deposits, radiator issues or broken water pumps. Regular inspections may help avoid overheating issues down the road. Come in today for a consultation on your coolant/antifreeze fluid.
How long can a car overheat before damage occurs? It only takes 30-60 seconds of overheating for permanent damage to infiltrate a vehicle. As soon as you notice signs of overheating, you need to act. Failure to do so might result in troubles like coolant leaks, damaged radiator caps, and a faulty cooling fan.
Don`t Ignore The Problem:

An engine overheating can cause serious damage to the engine itself and diminish a car`s fuel efficiency. If you think your engine is overheating, pull over and call a tow truck or a mechanic.

Technically speaking yes you can use plain water in your cooling system but it isn`t recommended as a long term solution and certainly not in extreme weather conditions.
An overheating engine won`t resolve on its own, even if it seems to be fixed after you add a little coolant. It will only get worse if left unaddressed.
Why is my car overheating but it has coolant in it? It could be that the coolant concentration is not correct, or you may have a bad thermostat, a failed water pump, broken drive belt, or a bad radiator or radiator fan.
If the coolant tank is full, the problem may be electrical or mechanical in nature, in which case a tow to the nearest repair shop is definitely in order. A leaking hose, worn or broken fan belt, bad water pump, or malfunctioning thermostat may be the culprit.
That said, a severely overheating engine can cause the cylinder walls or the pistons themselves to warp, bend and deform. This will cause the perfect seal between the piston and the rest of the engine to lose integrity. Oil could be forced past the piston rings and into the engine, where it will burn the oil.
One of the most common causes of overheating is problems with the radiator. Your car`s radiator pulls heat away from the engine to keep it cool. Sometimes, radiators can fail, or debris and particles can build up and stop the radiator from working properly.

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

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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.

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Heater not working reliably, is it caused by a bad thermostat?
ANSWER : From what you’ve described, it sounds like you have a stuck open thermostat. I’d recommend replacing the thermostat to see if this is the cause of the slow heat up of the vehicle since it’s a relatively quick repair. In an area like that it sounds like you’ll will need the heat in the winter very badly and as soon as possible. I would also recommend getting a coolant flush as it may help clear any possible blockage in the heater core. To avoid any unnecessary repairs, consider YourMechanic, as one of our mobile technicians can come to your home or office to diagnose your heating issue and make the necessary repairs.

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Vehicle at running temp, turn on heat, no heat – stomp on gas, there is heat – ??? 2004 Jeep Liberty
ANSWER : Hello – regarding your lack of heater function unless the engine is revved up a bit, you have a coolant flow issue. This could be caused by a worn water pump (engine might be running warmer than normal?), a partially blocked heater control valve (adjustment problem or failed heater control switch), or clogged cooling system that simply has poor flow. I would recommend an inspection of the heater & cooling system by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.

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Car heat is cold until I add water and over heating with out telling me
ANSWER : Hello, thank you for writing in. There seems to be an issue that we need to take on first and foremost. This is the fact that you are having to add coolant to the system. This means the coolant is leaking either externally (onto the hot engine), or internally (being consumed with the air/fuel mixture). The best way to tell is to simply run the vehicle and watch for the leak. If the engine is consuming the coolant, you are likely seeing white smoke from the exhaust. This is most commonly resolved by replacing the head gasket. Common components to look for an external leak with are the thermostat and the water pump. Both would cause the symptoms you are explaining. Fore more help with the issue, contact our service department to schedule an appointment.

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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.

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Engine is over heating and I’m not getting heat. 2001 Pontiac Grand Am 3.4 V6
ANSWER : Hello – I agree with your diagnosis – a water pump failure is a prime candidate for both overheating and a "no heat from the heater". Lack of water flow will cause both symptoms, and cause damage to the engine in minutes. I would recommend a thorough examination of the cooling system immediately. A mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.

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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.

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