I add coolant, it stays at 195 for about 20 or 30 miles. Next time I get in, the temp is dancing up and down because the coolant is gone. I can find any obvious leaks, I just replaced the stat, there's no coolant in my oil and it's not smoking. Any suggestions on where it's going?

 

put some UV dye in it and drive it for a couple of miles. then get underneath with a UV light. It sounds like intake gaskets to me. The stock ones always go on these. When mine started leaking it leaked down the back and I never saw it.

 

It does sound like the intake manifold gasket is leaking. The coolant is going into the engine combustion chamber and is being burned up and not leaking out. The fact that the coolant is not being mixed into the oil doesn't meant the IM gasket is not shot.

 

Also consider testing the cooling system for traces of combustion. This can help determine if you have a bad head gasket rather than just an int man leak. An emissions test shop can often 'sniff' the radiator for signs of a blown head gasket. Or you can use one of the various additives that detect emissions that have mixed in with the coolant.

 

found intake manifold gasket failure and repaired it. Runs like new now. 👌👍