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Q: There is an antifreeze leak on the passenger side that occurs when the vehicle is on for a long period of time

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I have been having antifreeze leak that happens when I have the vehicle running for a long time so far I have a new radiator new thermostat new water pump they did a pressure test and they still can't find no leaks the leaks occurs when I drive the vehicle for a long period of time but sometimes I feel like it has a mind of its own and leaks on the passenger side sometimes I can smell the antifreeze when I'm driving. I'm just wondering if any mechanics have any ideas?

My car has 75000 miles.
My car has an automatic transmission.

I would introduce UV leak detection dye into the system, pressurize the system while cold, and leave the system under pressure overnight (the pressure will slowly bleed off somewhat but such will not affect the test). If there is any external leak of significance, it will show up under the UV light.

If no leak is present and yet you still have a leak once the engine runs and gets hot, that means that the leak is between two surfaces that are opening up under hot engine operation. But the same protocol applies. That is, at that point, inasmuch as the leak detection dye is still in the system, you should just let the engine cool completely and use your UV light source again to methodically check all of the obvious possible areas of the system that could leak.

I recommend having a certified mechanic, such as one from YourMechanic, perform an inspection to determine the source of the coolant leak and suggest any needed repairs.

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