Ac Gauge Goes Up And Down. If the temperature gauge goes up and down and no heat. This is more prevalent on a hotter day.
DIY Auto Service AC System Diagnosis by Symptom AxleAddict from axleaddict.com
The coolant passageway might be blocked with sediments or rust. If your car thermostat keeps going up and down. then there are chances that the cooling system has trapped air inside it. If there are readings on both the high and low sides but they are not the correct specified pressures. it means that certain parts of the ac system are not functioning properly. such as the expansion valve. compressor. and clutch.
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If the needle goes to about the middle of the gauge. that means the engine has reached normal operating temperature. usually between 180 an 210°f. The air blows hot when the gauges go down. and cool when they go up.
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This is why the fan turns on and may run after the car is turned off. It goes up quickly after starting. then stabilizes.
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Air pockets in the cooling system The air blows hot when the gauges go down. and cool when they go up.
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This is more prevalent on a hotter day. You will see the low side gauge at 45 psi. drop quickly to 20 psi. at which point the compressor will cycle off.
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The air blows hot when the gauges go down. and cool when they go up. Again this is a guess.
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If your car thermostat keeps going up and down. then there are chances that the cooling system has trapped air inside it. You may want to check out clogged components such as the heater core. radiator hose. coolant level. thermostat. or water pump.
This Is An Electrical Problem.
The engine temperature sensor or associated wiring is failing causing the temperature gauge to drop to zero and the engine control unit/computer/module is shutting down the ac to protect the engine. But when i got off the freeway then drove about 5 miles off freeway. i came to a stop sign. then my engine light came on. and smoke was coming out under the hood. and big clouds of white smoke form tail pipe. The main reason why car temperature gauge goes up and down while driving is because something is not working properly in your cars cooling system.
The Air Blows Hot When The Gauges Go Down. And Cool When They Go Up.
If there is a blockage on the suction side of the compressor (blue gauge) the pressure will fall. It could be the radiator fan. water pump. thermostat valve. coolant. or the gauge itself. Okay.the ac seems to be going on the brink.alternately blasting hot and cold air.
Discussion Starter · #1 · Aug 31. 2009.
If your car thermostat keeps going up and down. then there are chances that the cooling system has trapped air inside it. Then the low side gauge will climb back up to 45 psi as the high and low side equalize. You will see the low side gauge at 45 psi. drop quickly to 20 psi. at which point the compressor will cycle off.
To Fix Either Of These Issues. Wed Advise That You Engage A Proven Auto Mechanic.
The coolant passageway might be blocked with sediments or rust. It goes up quickly after starting. then stabilizes. There may be several reasons causing your temperature gauge to fluctuate or go up and down.
The Most Common Reasons For The Pressure Gauge To Indicate A Red/High Pressure Reading Are The Car Is Not Running. Or The A/C Is Not On With The Fan Switch Set To High And The Temperature At Its Coldest Setting.
When the coolant goes through the heater core it gets cooled off enough that when it returns the thermostat closes again momentairly. If there are readings on both the high and low sides but they are not the correct specified pressures. it means that certain parts of the ac system are not functioning properly. such as the expansion valve. compressor. and clutch. The air pressure gauges are electronic pressure sensors plumbed into the primary and secondary air lines in the dash.