What causes my car to keep overheating?

ANSWER : Hi there – you may have 2 related events here, a coolant leak, and a problem with the heater system. The current issue may be air inside the cooling system, which can cause overheating, and a lack of heater function. The lack of heater function could have 5 causes: the engine is not getting up to correct temperature (center of the gauge) due to a malfunctioning thermostat, the heater control valve is not letting hot coolant into the heater core, there is a restriction in the heater system that is preventing adequate hot coolant flow through the heater core, the heater fan is not working to transfer heat from the heater core to warm air for the passenger compartment, or the air blend doors inside the heater are not working properly to route warm air to the desired vents. I would recommend a heater system inspection](https://www.yourmechanic.com/services/heater-is-not-working-inspection) 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.

ANSWER : There are reports that the replacement alternators will not communicate with the engine computer and will not charge correctly. I recommend using only the manufacturer approved replacement part. It can be new or remanufactured but approved for use in the vehicle. Some lower cost alternators on the aftermarket will have charging problems since they will not communicate with the ECM on the vehicle and will stop charging.

ANSWER : Coolant leaks can occur because of cracked hoses, leaking gaskets, faulty water pumps, or damaged radiators. When the coolant level goes low, the engine will start to overheat due to the low coolant level. I would first recommend giving the cooling system a visual look over. If it is not obvious where the coolant leak is coming from, I would recommed having the cooling system pressure tested in order to determine the leak source. If you would like to have your cooling system pressure testedcoolant is leaking inspection, consider YourMechanic, as a certified technician can come to your home or office to inspect your cooling system.

ANSWER : Hi there. What had happened is the wrong key set the security to the vehicle. This is to prevent the vehicle from starting with the wrong keys. Try removing the battery cables (+) and (-) for 13 minutes. During that time, put the original key in the ignition and turn it on. Activate everything in the car even though there is no power. Then remove the key and hook up the battery cables. The computer should have reset and reset the security. If the security is still being tripped, then I recommend seeking out a professional, such as one from Your Mechanic, to help you

ANSWER : It sounds like you have 2 problems here, the starter and an engine stalling problem. The starter problem is probably the starter solenoid, a power switch (integrated into the starter assembly) that takes a small current from the ignition switch and engages a large current at the starter. The contacts in the solenoid can burn over time, "sticking", which can cause the starter "run-on" like you described, and a "no crank" condition, because the same burned contacts don’t pass heavy current very well. The poor idling may be due to a dirty idle air control valve, dirty throttle body, or air leak in the intake system of the engine. I would recommend having YourMechanic dispatch a mobile, professional mechanic to your location to do a (Starter Replacement)[https://www.yourmechanic.com/services/starter-replacement] and car starting trouble inspection.

ANSWER : Thank you for writing in! Typically the thermostat and water pump are the primary sources of overheating on a 1997 Toyota Corolla. However, since the fluid never left the reservoir, it could be caused by a blockage in the coolant tubes; such as an air bubble. A good bet would be to have one of our local mechanics complete an overheating inspection. This would reduce the frustration of guessing and allow them to pinpoint the source of your issues; so that they could be fixed sooner rather than later.

Best of luck!

ANSWER : It sounds like you are getting a bad reading from the crankshaft or camshaft sensor. Have the computer scanned and the data stream monitored for problems with the two sensors to see which one is causing the stall and erratic RPM signal and causing the gauge to read high. If you need help, have a certified technician scan the computer scanned for any existing trouble codes to diagnose the stalling issue and let you know what repairs to move forward with.

ANSWER : It sounds as if you have a major concern with a great deal of fluid loss. In many cases, a component or seal failure may cause a large amount of fluid loss if it has gone unnoticed for some time.

My best advice to you is to hire a professional to look over the vehicle to find where the fluid loss is happening and make an attempt to correct the situation. With such a large scale of fluid loss, there may be multiple problems.

If you decide to get this fixed, consider enlisting a certified mechanic, such as one from YourMechanic, who can diagnose the source of your leak and perform any repairs that are necessary.