[forcedfx]

I see the engine block has a single 36.6mm freeze plug but I can't find any info on where it is located. I tried searching but didn't find anything useful and it looks like the search functionality just stopped working.

The wife's car has a slow coolant leak so I'm beginning the search for possible culprits.

 

[zmaninco]

I highly doubt it is the freeze plug. The most common failure is the o-ring for the coolant temp sensor located on the back of the head. Over time this o-ring begins to decay and I have seen them where there is almost nothing left.

look behind your head, look for pink crusty stuff. The coolant does that.

 

[DerhsLacidar]

A guess off the top of my head would be the coolant flange at the back of the cylinder head as well.

Be a little more specific as per a location of leaking coolant... There are many common areas that leak over time. Look for the pink crust!

 

[Steve in Chicago]

While you're searching for the leak, pay attention to what you're topping the cooling system with. Adding other formulas of coolant in with the factory G12 coolant is bad. The two types react chemically and form a goop that will block up passages in the heater core and radiator.

Do some searches on the topic if this is new news to you. There are many threads talking about this, how to deal with it and alternate coolants.