The Nissan Path

This morning, while checking fluid levels (cold), I noticed that the coolant level in the recovery tank was high (about 1 quart).
Checking the fluid in the radiator, it was low (about 1 quart).
There are no leaks, the heating system works normally, and there are no other symptoms of anything being wrong.
Can anyone suggest why the levels would change like this?

It seems to be a common idiosyncrasy of our systems.

..that coolant has a lot easier time going into the overflow but not necessarily back.
My Xterra (exact same engine, radiator, hose, overflow tank setup) was over 2 quarts short in the radiator the other month even though overflow tank was plenty full.
No sympton from the tempt gauge even as the vehicle had been driving in 96F traffic jams.

I had not checked the radiator itself since the overflow always looked good.

I have since replaced both pressure caps.
Albeit they were not OEM and even though the issue has not returned but I have done not a lot of driving with that vehicle so I think for my peace of mind I will go to the Nissan dealer and buy new caps for both ( they are different caps for overflow and radiator).

Thanks!
I just checked the other R51 (we have 2, i know, gluttons for punishment).
It had exactly the same levels as the other.
I topped them both off (radiators), and will monitor.
If I see repeat performance on either, I'll report back.
Thanks Again!

I join this club as well..have two R51 vehicles...same has happened.

overflow shows perfect level...radiator was low..heat and air worked..temp gauge was as always...

Thanks!

Which rad fluid did you guys go with?

Personally, I use Pentosin Pentofrost. They make the OE coolant for Nissan. Pentofrost A2 is the green coolant Nissan used to around 2010, when they started introducing blue, extended-life coolant, which is Pentofrost A3. Pentosin can be found at a number of auto parts stores, including Autozone, and you can find it at Rockauto or on Ebay.