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Coolant Low When Hot, Full When Cold. Why?

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  • Coolant Low When Hot, Full When Cold. Why?

    I have a bit of a weird situation here.

    I recently had my coolant flushed and replaced (Toyota Long Life Coolant). Upon getting the unit back, everything seemed normal. Then the day after, as I was driving, I noticed the temperature gauge start creeping up to the H mark, then go back down to the middle. It kept fluctuating like this until I reached the shop where I had this done. They checked the coolant expansion tank and it was empty (They didn't burp the system of air). They refilled the tank as it was running until the coolant in the tank was no longer going down.

    I then drove home and the temps were now steady (middle of the temp gauge the whole time). After parking the car while the engine was still hot, I checked the level and the coolant level in the tank was now pretty low close to the bottom.

    The next morning I checked again as I planned on topping it up and it has mysteriously gone back up and now at the LOW marker.

    I am very puzzled as this is the opposite of what is supposed to happen. Is there still air in the system that may be causing this?

  • #2
    unfortunately i suspect its a leak in your EGR cooler. its a known issue on the 1GD motors and the leak can only be seen with a borescope. The coolant leaks inside the intake pipes where you cant see it. Get a pressure test done and advise the machanic to look at the EGR cooler. Toyota may cover it under warranty if your dealer goes in to bat for you
    2019 GX , in White


    • #3
      Hi EGR cooler is common problem in this situation. I had the same problem and I by passed the EGR cooler with few coolant hoses. My heating and loss of coolant problem was gone. I drove the car for one month to confirm the problem. I got the new EGR cooler replaced and now the problem is gone for ever.