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Master Auto Tech.
Master Auto Tech., master tech.
Category: Hyundai
Satisfied Customers: 612
Experience:  A.S.E. Master technician. Over 20 years working on import & domestic. Owner/operator of an auto shop
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I've got a 04 Hyundai Sonata V6. I've replaced the

Customer Question

I've got a 04 Hyundai Sonata V6. I've replaced the thermostat, radiator, coolant temp sensor. Have a 50/50 mix coolant ratio, I've bled the car on ramps to try to aleviate any air in the system. When parked in the yard idling, when the car gets up to temp the fan will come on. When I turn on the fan inside the fan to blow air the temp gauge goes up at a pretty significant rise... I turn it off and it will go down. When driving down the road the car will stay just under half way on the temp gauge, if the headlights are on the car will get just under 3/4 high. I turn the lights off and the temp goes back down to just under 1/2 way. I cannot figure out what is wrong with this car. The A/C has a leak so we don't run it at all.
Submitted: 1 year ago.
Category: Hyundai
Expert:  Master Auto Tech. replied 1 year ago.
I'm sorry you are having problems with your vehicle. I will try to help.I'm a full time mechanic and have been a mechanic for over 20 yrs and I work part-time here on JustAnswer to help you and others repair their own vehicles, and I get credited by your ratings.. So before leaving the site make sure and leave me a rating. You can still reply to me as many times as neeed, even after the rating.. I will need for you to be my hands and eyes since I'm not there.So it's hard to say for sure, but it sounds like your instrument cluster is acting up. Or there is a bad ground for the cluster. But to know for sure, do you have a scanner with data? If you have or can borrow one, watch the temp there and see if it is fluctuating like the gauge. If it is then it's a real problem w the cooling system. If it isn't fluctuating the the problem is in the wiring or cluster.
Let me know.Thanks