Engine overheats when A/C is turned on

2002 MITSUBISHI LANCER
207,000 MILES • 2WD • AUTOMATIC
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CHRISTOPHER RIVETT
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  • 1 POST
My question is, My A/C works, but when I turn it on the temperature on the engine will go almost all the way up and start to overheat, so I have to turn the heater on and let it run and the temperature will come down. What could I do to help the circulation in the engine so I can run the A/C without engine trying to overheat? Also, the thermostat was replaced little over a year ago. Thank you for any suggestions or help. God bless.
Aug 27, 2020 at 10:59 AM
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KASEKENNY
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  • 18,907 POSTS
This is most likely due to a couple things. First the compressor may be locking up causing an additional stress to the engine overwhelming the cooling system. The other possible causes are air flow issues. This is a restriction in the radiator is the most likely cause.

Let's start with pressure testing the cooling system.

https://www.2carpros.com/articles/radiator-pressure-test

https://www.2carpros.com/articles/symptoms-of-an-overheating-engine

Let me know what you find and we can go from there. Thanks
Aug 27, 2020 at 5:26 PM