Could this be coolant leaking? Pics Inside

ok I was doing an oil change a few days ago. While looking around in the engine compartment I noticed a PINK patch of something.

So at first I just thought it was some kind of marker from the factory or something,then I looked closer and shot some pics...

I positioned my camera under what I think is part of the oil cooler or maybe it's even the thermostat housing (not sure)

But found some dried up pink powder under it

Looks like I had a coolant leak at one time. I checked very close and nothing is wet or leaking now and I never leave any puddle or anything in my driveway

Anybody have any idea what could be going on?

My radiator is full and my overflow jug had to be topped off twice in 5 years. I think I added like 4 cups of coolant to the jug in 5 years

My Interceptor scan gauge runs at 186F degrees when driving down the road

Thanks for any thoughts on this

 

Is that under the coolant reservoir tank ? Maybe the coolant came from there (normal), the fluid is dried out so it doesn't look like a leak.

 

No this is not directly under the coolant jug..

It's where the upper radiator hose runs to from the radiator also the oil cooler lines run to this junction

I was thinking it's the thermostat housing

I'm gonna clean all the pink powder up really good and then keep a close eye on it

Thanks for any other info