After fixing my radiator, radiator hose, thermostat, and idle control valve my car continues to idle very high and run hot. Help??
When I crank my car it idles extremely high but I have already changed the control valve. Also, I have changed my radiator, radiator hose, and thermostat all which needed to be changed and my car still runs hot. Any professional suggestions because family members that know about cars and mechanics have all said that it can only be the heater core or the water pump but I don't know which one it is and I am afraid that I'll fix the wrong thing.
My car has an automatic transmission.
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
Hello, high idle can be represented by many conditions. A heater core would not cause this unless you have a coolant leak and the core was leaking. There are tests that can be performed to test a water pump (coolant pump). A vacuum leak can create high idle and even a high engine temperature. A suggestion is to read engine data and any fault codes in the system. This is done with a scan tool. The scan tool can read data which will give you information on the operating systems of the vehicle. If you’d like, a certified technician from YourMechanic can come to your location and do a complete evaluation of the overheating issues.
How to Identify and Fix Common car Problems ?
Our sources include academic articles, blog posts, and personal essays from experienced mechanics :
The most common problem is a faulty fuse. In modern vehicles, engine idle speed is most often controlled by the idle air control (IAC) motor. This can be impacted by bad fuses in many different electronic systems in your car. Next, your high idling could be caused by a computer malfunction.
Among the potential underlying causes are vacuum leaks, EGR system malfunctions, malfunctioning oxygen sensors, dirty fuel injectors, fuel pump malfunction, faulty spark plugs, a faulty mass airflow sensor, or a faulty throttle position sensor.
The engine`s oxygen sensor will detect the extra oxygen entering the engine via the vacuum leak which will alert the engine`s computer that the exhaust is running lean, which will prompt the computer to pump in additional fuel, resulting in an abnormally high idle.
Faulty Thermostat
The thermostat is a device that regulates coolant flow to the engine. If the thermostat is damaged, it can cause the engine to overheat while idling. This is because the coolant is not flowing properly and cannot dissipate the heat properly.
Replace the sensor with a compatible one and correctly install the crankshaft position sensor to ensure that the engine runs optimally and safely. A qualified technician can prevent further issues with RPM fluctuations while driving by installing the sensor correctly.
Worn Transmission Fluid (Automatic Transmission)
Over time, the transmission fluid gathers dirt and grime. This can cause the engine to run roughly, stall or fail to accelerate when you press down on the gas pedal. You may need to have a transmission fluid change before more damage is done.
The idle speed should feel consistent without skipping or slipping. In most of today`s cars, an idle speed of 600 to 1000 RPMs is average. If your car is idling rough, though, it won`t feel smooth. The RPMs will jump up and down, for example, or they`ll fall below 600 RPM (or whatever is typical for your vehicle).
An idle air control valve, also called an idle air sensor control motor, is an electrically operated valve that controls the amount of air that bypasses the throttle plate in cars with a fuel injection system [source: Autozone]. This causes the idling speed of the engine to change as needed.
The fault with a coolant sensor can manifest in two ways- A coolant temperature sensor that always reads cold may cause the fuel management system to mix fuel with less oxygen and waste fuel. On the other hand, a sensor that always reads hot can cause problems such as stalling, hick-ups, and rough idling.
You can check to see if you have faulty wiring by using a voltmeter. Keep your engine idling and then test the wires with the voltmeter to see if there are any inconsistencies. Your mechanic can easily perform this test for you. If the wires are fine, then the gauge itself might be damaged and may need to be replaced.
Here are some possible reasons your RPM is going up and down while driving: Worn-out spark plugs. Vacuum leaks. Bad idle air control valve.
Your tachometer needle will bounce up and down if your engine has a vacuum leak. The vacuum created in the combustion chamber is used as a power source, and, as such, it is routed through the engine to various locations using vacuum hoses. Over time, Collins Auto Care advises that these hoses can start to leak.
The idle air control (IAC) valve is located on the throttle body of fuel-injected engines. This valve works with the vehicle`s ECU to electrically regulate airflow to the engine to ensure smooth idling.
Removing the idle air control valve can therefore have a negative impact on engine performance. In some cases, it may even cause permanent damage to the engine. As such, it is generally not recommended to remove the idle air control valve unless absolutely necessary.
Automatic transmissions are usually designed to operate between 500 and 8000 RPM depending on the engine. With diesels automatic transmissions are programmed to operate at lower RPM (500- 5000 RPM) than with gas( petrol) engines.
What RPM should a car drive at when accelerating? When accelerating your vehicle, it is best to stay within a 2000-2500 RPM range. This will give you enough power to reach an acceptable speed level while also ensuring the engine stays within safe operating limits.
The vehicle may need to be driven for 10 miles (16 km) or more to relearn the idle and fuel trim strategy.
For a passenger car engine, idle speed is customarily between 600 and 1000 rpm. For medium and heavy duty trucks, it is approximately 600 rpm.
For regular cars, idle speed is typically between 600 and 1,000 rpm, just enough to keep the engine`s ancillary systems going, but not enough to move the car forward much.
Normal idle speed for your vehicle, once the engine is warm, should be around 750 RPM (roughly). Two thousand RPM is significantly out of range high, even for a cold engine. The occurrence of this high idle speed might be a coincidence and thus not related to the alternator repair.
The most common cause of the shaking most often happens near your tires and rims. The tires and wheels connect your vehicle to the road, and if anything is a bit wonky, will notice. It may be something like a broken transmission or a broken control arm.
Function. The functional objective for the crankshaft position sensor is to determine the position and/or rotational speed (RPM) of the crank. Engine Control Units use the information transmitted by the sensor to control parameters such as ignition timing and fuel injection timing.
With the engine not running and the key on, the MAP sensor should read around 28-inHg. When the engine is started and idling, the vacuum of the engine should reduce atmospheric barometric pressure by 20-inHg.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
After fixing my radiator, radiator hose, thermostat, and idle control valve my car continues to idle very high and run hot. Help??
ANSWER : Hello, high idle can be represented by many conditions. A heater core would not cause this unless you have a coolant leak and the core was leaking. There are tests that can be performed to test a water pump (coolant pump). A vacuum leak can create high idle and even a high engine temperature. A suggestion is to read engine data and any fault codes in the system. This is done with a scan tool. The scan tool can read data which will give you information on the operating systems of the vehicle. If you’d like, a certified technician from YourMechanic can come to your location and do a complete evaluation of the overheating issues.
High idling, jumping while idling, idle air control valve code
ANSWER : Hi there. This can be caused by the issues that you mentioned or a number of other things. You need to make sure all of the connectors are making good contact. I would then need to know what codes are in the computer to know if this is a circuit issue or not. Most of the time, it is not the circuit but instead a vacuum leak.
If there is a vacuum leak, then the vehicle will act like this and the computer cannot control the idle. Most of the time it is a bad hose or an EGR valve that is stuck open. That is the most common cause for this. I typically remove the EGR to check it to feel the diaphragm on the bottom of it to see if it is moving correctly. If you need to have this repaired, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose and repair your car’s idling issue.
Please help me figure out where my PCV valve and PCV Hose is!!!
ANSWER : Hi there. The PCV valve is located on bank 1; the valve cover closest to the cabin. It is usually found under the intake plenum towards the passenger side of the vehicle. The hose will be attached; or loose. Please understand that a code retrieval and an internet search is not a proper diagnosis as there are several other possibilities that can cause the code to set. Some of the possible causes could be spark plugs, ignition coils, intake manifold leaks, intake plenum leaks, vacuum hose leaks, failing airflow meter, failing O2 sensors, exhaust manifold leaks, low fuel pressure, failing ECU, faulty wiring harness, failing injectors, etc… As you can see, the list of possibilities runs on and on. This is where the expertise and experience of a qualified technician with the proper diagnostic tools and procedures becomes invaluable. I strongly suggest having a qualified technician perform an inspection to avoid replacing unnecessary parts and determine the exact cause of the code. Your Mechanic has several available technicians that can assist you with a check engine light inspection.
Got my rear main seal fixed, but my car keeps having a rough idle, cutting off & the Electronic Throttle Control Light is on.
ANSWER : It sounds like you may have a faulty electronic throttle control unit. The electronic throttle unit opens and closes the throttle blade based upon input from various engine control sensors, including the accelerator pedal. This unit also controls, among other things, the cruise control function as well. When this control unit fails, this may cause intermittent stalling issues and rough idle problems. This is usually repaired by removing and replacing the throtte control unit. I would suggest having an expert from YourMechanic come to your location to diagnose and inspect your vehicle at your earliest convenience.
My car is running hot, what could be the problem?
ANSWER : There could be an issue with the cylinder head gaskets. Antifreeze can break down and become acidic if not replaced as normal maintenance. The head gasket material erodes and can cause engine compression to build up in the coolant system. This will prevent the flow of coolant which can create an overheating condition.
There is a test that can be done to check whether there is carbon monoxide in the coolant system; it involves special equipment.
I recommend having your overheating condition inspected, and perhaps have a block test performed.
my car is running hot and i have already changed my thermostat and sensor. a coolant build on the hose beside the housing
ANSWER : The engine temperature should be measured independent of the dash gauge and/or a scan tool should be used to read the temperature sensor directly to determine what the operating temperature actually is. If the car is in fact overheating, it’s best not to drive it because overheating can warp the cylinder head and/or engine block causing costly damage. The most common causes of overheating include low coolant level, 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 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 promptly. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
Car is idling at high rpm’s and when the days are hot the car cranks but doesn’t turn on and also exhaust is smoking when i rev it
ANSWER : Hello – your symptoms suggest worn piston rings or valve stem seals (smoking), and a possible air leak in the intake, or idle air control valve sticking open (high idle). Both are signs of a higher-mileage engine with significant wear. I recommend an engine inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.
Engine won’t start while hot after replacing head gasket.
ANSWER : Hi there. The code 12 is for your distributor has no reference. When the engine gets hot, the secondary circuit on the ignition coil gets hot and will not work. I recommend replacing the ignition control module and then recheck. If the symptom continues, then you will need to change the ignition coil. As for the brakes not working, check the master cylinder for the fluid and make sure that its full. Look for any signs of brake fluid leaks. If the fluid is full, the pedal is firm, and there are no leaks, then the brakes may need to be replaced with new rotors and new drums. If you need further assistance with the distributor and the brakes on your vehicle, then seek out a professional, such as one from Your Mechanic, to help you.
