Question about 2001 Kia Optima
I have a 2001 Kia Optima V-6 with about 88,000 miles on it. Temp on car is fine til I turn on the AC then the Car runs hot. I have flush cooling system and changed out fluids. Also have change out the Thermostat. Also both fan on the radiator are running when the ac is turn on. Any Ideas of whats making it run hot. Thanks Ron
I figured this out and fixed it on my 2001 Optima. Mine was an electrical problem, not an overheating problem. The problem shows up when there is a heavier than normal load on the electrical system. For most of us, this is when the air conditioner is running full-blast on a hot summer day. However, it was also occuring when I ran the heater full blast. The heater running full-blast should have lowered the temperature, not raise it. So I tested the coolant temp while the gauge was showing it overheating. The coolant temp was not increasing, but the gauge showed that it was. It is caused by a bad ground connection. Another test you can do to see if your problem is the same as mine is this. As soon as the engine is showing overheating, pull over, park the car and turn off the engine. Immediately start the engine again and see what the temp gauge shows. If it still shows hot, you'll know you've really got overheating coolant. If it goes back to normal range, you'll know it's just a bad ground connection. Turning off the engine eliminates the resistance in the electrical system that has beeen building up and causing an erroneous high temp reading.
To fix: Either find and clean ground connections throughout the vehicle until it fixes it, or do what I did. A mechanic at the Kia dealer showed me this. I ran a new wire from an empty bolt-hole on the top of the engine to a bolt into the frame behind the engine. I only added a 6 inch wire and a new bolt into the top of the engine. The bolt into the frame was already there, so I just removed it, put the wire under it, and replaced the bolt. It created a redundant ground that prevented the build-up of resistance that caused the erroneous temp reading. It was a 5 minute fix and it has never done it again. Kia knows about this problem and they put out a post to their shops on how to fix it.
Posted on Oct 01, 2008
I have the same car. try a new coolant temp sensor. or check the wiring. when you put your blower on full blast, its gonna have more juice running through youre wires, which puts you more at risk to short out your temp sensor. which could kick both fans off; causing the overheating. or it could be a bad temp sensor.
Posted on Dec 22, 2008
I had the same problem as above..... did the thermostat change, no luck......I changed the temp sensor and no luck......after I read this post I went home and found that I did have a ground wire from the firewall or frame of the car ......the only thing was that the wire was not only loose on the end that connected to the engine, the end that connected to the engine was bolted to a plastic cover over the timing gears. I moved the cable from that position to an all metal location on the engine and "bang" problem solved.
I ran the car as hard as possible with the AC on full blast while going down the road and while idling and no problems. Thanks guys for the great solution to a very nagging problem.
Posted on Aug 27, 2009
Could it be a funky temp sensor? mine does the same thing, getting worse now that I've changed the coolant.
Posted on Oct 01, 2008
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Posted on Jan 02, 2017
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