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Transmission and Overheating Issue - '03 Sonata

thechefjeffthechefjeff Member Posts: 1
edited November 2014 in Hyundai
First of all, I have basic knowledge of my car and in cars period so pardon my lack of detail I'm giving.

This is my issue and just want some feedback from knowledgable people like yourselves.

So I have a 2003 Hyundai Sonata with over 136,000mi on it. My Transmission had a 3rd gear ratio problem and was constantly slipping. I went to my local mechanic and I swapped out my old broken one for a new (used) transmission that had under 40,000mi on it. All fixed right? Not at all... the transmission was smooth but another issue arose.

I drove it home and shortly after out and about. That's when I noticed that my car was over heating. No check engine light was on, but I took it back and the mechanic he replaced the thermostat. I drove it off and it was fine for a little bit. I noticed that while driving on the freeway the temp gauge was fine but as soon as I hit traffic or went idle at a stop light on the streets the temp gauge would shoot straight up!

I took it back and the mechanic and he said it either has to be because the water pump is messed up or worse the head gasket. He checked the water pump and it was fine, the fans are fine too. So he said it has to be the head gasket. Mind you, I never had this issue of overheating pre transmission change.

So I ask all you knowledgeable now this. Did my mechanic do something while swapping out the transmission to affect my cooling system? Was this a problem bound to happen and just showed itself once the new transmission was put in? Is there any other issues that could be affecting the overheating besides the head gasket? I'm nervous that once he changes the head gasket, that it'll overheat again and then we'll be stuck and I'm out more money.

I appreciate any constructive feedback.




  • roblucirobluci Member Posts: 2
    Have you checked your fluids? Low coolant level leads to overheating which is the usual cause of overheating. I've experienced overheating due to a blown head gasket. Had it replaced yet turns out there were hot spots. Maybe you have a leaking or blown head gasket. Just make sure that's a trusted service provider so he won't end up milking you. Ask him questions and if he quotes you do ask competitors too. That's how I got fair deals.
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