Taco coolant issue

In my 2017 and in my son's 2019 Tacoma with the V6 I have noticed an odd issue. Despite no indication of overheating both vehicles appear to be losing or using coolant in such a way that the level in the overflow tank drops below the recommended level at hot AND cold. It is very easy to see looking at the overflow reservoir tank that fluid is being sucked out then returned as there is dried coolant product noted on the outside of both tanks where the overflow hose connects. I have never seen this before in any of my other Toyota vehicles. Is this normal as being an old school back yard mechanic I would think either the thermostats are sticking or both vehicles have bad sensors which would be odd?

 

Turn off the radio and listen to that sweet shifting transmission.

Oops wrong thread

 

There have been a couple threads about a coolant pipe in the back of the engine that leaks. It is hard to see it.

 

I'd first expect a leak ... Put cardboard under the engine area for a few days/week. Try to put it in the same place every day/night. Check to see if you can locate the general area of the leak (i.e., Under Water pump shaft seal, Over pressure/fill cap line, tranny cooling lines, Hoses, etc.).

If no leak seen I'd bring it to a decent garage and have them pressure test the cooling system. If the pressure drops and no leaks - it may be Head gasket - and then a cylinder pressure test should be done .... JMO Hope it's a leak

 

https://www.tacomaworld.com/threads/2017-tacoma-coolant-leak.492860/

 

Not sure how bad yours is, but after 20k miles mine is a smidge low, but not below the low line at cold temp. I have a small streak of dried coolant under the overflow hose.