Losing Coolant

S10 Blazer, 1992, 4x4, 4.3L, Auto, TBI, 216500 miles.

I'm losing coolant but I can't find where. Gad mileage hasn't changed and there's no smoke coming from the tail pipe. Where could I be losing it from? How can I find the leak?

For hard to find leaks they make a coolant leak dye kit.

Also a rad pressure pump helps.

Always check cold and warm and hot.

Many places they can leak.
Rad and hoses and pressure cap and coolant tank.

Water pump and intake manifold outside head gasket leakage.
On water pump watch the weap hole underside.
A water pump can leak at times and not other times.

Heater core and heater hoses and couplers.

Also freeze plugs.

Put some leak dye in and pressure test it cold and warm and hot and look everything all over good.
Then go over it with the leak dye light.
And be sure to watch the engine oil for coolant in it.

Good Luck

What are freeze plugs??

Core plugs or Frost plugs or block plugs or head plugs.
Them steel and brass plugs in block and head that pop out when coolant freezes or sometimes rust out

Where are those located?

Front and rear of engine and on both sides.
Some hid under engine mounts and behind starter and in bell housing on rear of engine and some behind stiff on front of engine.
Also some heads have them.

Always look under engine for leaking freeze plugs.
Good luck