I have changed the sensor on the thermostat, the thermostat, and the water pump. As long as the air conditioner is running my car stays cool. When i dont have the air conditioner is not on the fan wont kick on until it gets to hot! Is it the fan? Or could there be another problem?
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Re: I have a 99 cavalier that is overheating.
Check your temperature sending unit plug and wiring. if there is any corrosion it can cause the signal to be out of range...If it's out of range it can delay fan start up. Works like this: sender sends info to the computer, computer sends ground signal to relay, relay completes power to the fan. If the fan works on a/c, then the fan motor is good and does not need testing. A/c bypasses auto control and keeps fan on as long as compressor is running. Also, you can have the system tested using a heat sensing "gun" Your gauge may be off a little on the high side. Unless it is actually overheating, there may not be any problem at all. The gun test can also detect "cold spots" on the radiator which indicate a flow problem. That too can cause your symptom. Don't forget your radiator is ten years old and likely is nearing the end of it's service life. Internal blockage of core passages is common on older radiators. As long as you have no external leaks and engine internal gaskets are good, something here has got to help! Good luck!
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Hello glongoria8 and thank you for asking your question, on Fixya.
Here is a simple process that will walk you through a few steps that
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So here is the link to: How to diagnose your overheating Chevrolet Cavalier engine
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During the summer, you can run without a thermostat without any significant problems. In cold weather however, having no thermostat will prevent your car from warming up to normal operating temperature in a reasonable period of time, which will put additional stress on the engine and reduce your gas mileage substantially. You will also get virtually no heat to the passenger compartment. Two things you should check in regards to overheating: Is your water pump working and does your radiator fan switch on when the temperature rises above @190 degrees? If the vehicle has over 100,000 miles on it, you might as well replace the pump now. Don't use a rebuilt pump. They are ****. Get a new pump and a good quality thermostat. If the fan doesn't come on when it should, you probably need an new fan switch/sensor. These are inexpensive and easy to replace. Also check for signs of damage to the wiring leading to this sensor, and check the fan fuse and relay. Finally, make sure that your antifreeze mix is no more than 70% antifreeze to water for winter weather, or 70% water to antifreeze in summer. 50/50 is a good bet for year-round reliability, but a higher % water will tend to cool the engine more efficiently. Having said all that, I suspect your water pump is the main problem. If you notice a slow drip of coolant near the pump, you can be almost certain it has failed.
Overheating can be a mystery-but I find that most of this problem is putting in the thermostat backwards, and/or not getting all the air out of hoses(upper and lower)-posible that water pump is shot, and or fan belt that drves pump is no good(unless driven by timing belt)-flush radiator to make sure that isn't clogged up...
try priming the engine block & radiator with water though the hose's & any hose you can squeeze to pump out the air lock with the filler cap off when running, sounds too much air is is in the system & the pump won't work dry.
I had this problem a few times & I ended up practically forcing water into any hose I could re-attach quickly using a garden hose, as the heating system need's priming too !
Sometime a car will overheat it there is air int he system. You can buy a resivor that will screw tot he top of your radiator that is made for burping the system. This can be found at your local auto parts store.