i have a 2014 Ford Taurus limited 3.6 V6. 166XXX miles.
it has been loosing a lot of coolant and it’s not leaking
i add a little bit of coolant every day.
does it mean my water pump is going bad?
No, it means you more likely have a bad head gasket. A good repair shop can test for that.
A leak of this magnitude would probably be obvious, but you could use UV dye to make sure it’s not an external leak.
If it’s not an external leak, then it probably is the head gasket, unfortunately. Does your oil look normal or milky right now?
Have you checked your oil level recently? There’s a know design flaw with the transversely mounted Ford 3.5L/3.7L (your car has the 3.5L), in which the water pump starts leaking, but since it’s located inside of the timing cover (and run off of a timing chain), the coolant gets dumped into the oil pan. Coolant level will go down without signs of a leak. Eventually enough coolant leaks into the oil pan, the bearings get destroyed (coolant isn’t a good lubricant), and the engine is basically junk. If you check the oil level and it’s abnormally high, there’s a good chance that this is what’s happening.
At some point (I think it was for the 2014 MY) Ford started using a water pump with double gasket design with a weep hole between the two gaskets. So if the first gasket was breached, coolant would leak out of the engine onto the ground, which would hopefully tip off the owner. While the second gasket kept the coolant out of the oil pan.
As a bonus, there are rare times where the water pump will seize, and cause the timing chain to fail or jump time, which will also destroy the top end of the engine and dump a gallon or two of coolant at the same time.