I have a 2012 Nissan Frontier, V6, automatic transmission. I have a coolant leak that I can't figure out. I fill the coolant reservoir tank at night, next morning it's right where I left it. I then drive about 20 miles to work on mostly the Interstate. Check it when I arrive and the coolant is at the same spot. When I check it in the parking lot a few hours later, the coolant has leaked out onto the ground. The level is below the minimum line on the reservoir tank, but I can still see some coolant in the system. Is it possible the reservoir tank has a leak? Why else would it keep leaking to just past the minimum line but not beyond that? And why does it only start leaking after I drive it and it's been in park? It's odd to me that it doesn't leak when it's been sitting in my driveway, doesn't leak or boil over on the drive to work, but does leak after I drive it and shut it off.
I would purchase a dye kit and following the instructions add the dye to the coolant so that you can see exactly where the leak is coming from.
When you have the time, I would then duplicate the distance to work and drive back home and watch it to see what happens.
A piece of large cardboard could also be placed under the engine to help diagnose exactly where it's leaking from.
Is it possible the reservoir tank has a leak?
Of course. Remove it, fill it with water and inspect for leaks. Try different temperatures.
And why does it only start leaking after I drive it and it's been in park?
temperature , pressure, expansion etc. Several things at play here.
As the engine cools down and the pressure in the system decreases, the leak from what is probably a loose hose reseals itself. I would carefully inspect your hoses, the, as MMJoe said, the reservoir tank and last, the water pump. Just for quality, I would get a new radiator cap too.
