you may want to try a bottle of this
https://www.amazon.com/SUBARU-SOA635071-Coolant-System-Conditioner/dp/B00IGZP2UE

engine dead cold.... open the blue pressure cap, remove some coolant if
needed... pour the entire bottle in it... may be you will need 2 bottles...

dan

On Wed, Sep 4, 2019 at 8:09 PM Steven Shelton <shelton4@gmail.com> wrote:

> Actually I don't have a coolant pressure gauge, not even at home. I did
> check the hose clamps and they are tight. I took it to Culver's Auto Repair
> in Missoula. He could see no sign of a leak anywhere so  told me to just
> carry some 50% antifreeze with me.
>
> We're at Flathead Lake tonight. I just looked under the van and there's a
> small spot of coolant under the engine and some on the part of the head
> under the small hose to the thermostat. Not as much as in Great Falls,
> though. It felt dry under the hose. Weird.
>