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Q: My car is overheating and I would like to pinpoint the cause.

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I purchased this g35 recently so I don't now much about the prior history but what I do know is that it's now starting to overheat. First indication that something may be wrong with my cooling system was one night when trying to warm myself up inside my car I noticed that there was no heat. This was the first time I needed heat so I don't know if this was a new problem or old. I opened up the radiator made sure there was fluid present and tried burping it with the relief valve, no change. Next day while driving to work I noticed the temperature kept rising. Pulled over, waited for it to cool down, put water that I had near me in there. Temperature seemed fine. Couple days later same problem except this time it was not sovled. Thought it may be my thermostat. Changed it still no change. Now I am thinking it may be my water pump but I haven't noticed any leaks and the oil doesn't seem to be mixed with any coolant (as far as I can tell) and my radiator seem to be working just fine. Thanks

My car has 105000 miles.
My car has an automatic transmission.

Great description of the problem - your observations helped eliminate the issues it could possibly have. From what you’ve described, you may have a clogged heater core. Fix and flush your system. While flushing the system, make sure you look at the color of the antifreeze and see if you notice different colors. If so, then there is your problem.

You made a suggestion about the water pump. This could also be the cause, but I would try more simple solutions first and see if you can get it back to proper running temperature.

Note: A cracked head gasket doesn’t always give you signs like milky oil or oil in your antifreeze.

If you would like a more precise diagnosis of the issue, a certified professional from YourMechanic can come to your location to inspect the overheating problem and follow through with repairs.

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