The Nissan Path

So I been toying with the idea of doing a radiator flush as I may take the Nissan on a long trip.

The overflow always looked fine but tonite I decided to check the coolant level in the rad itself.
And under the cap there was no coolant that I could see..

No biggie I thought I just top it off with distilled water.
But it turns out it took half a gallon!

I never had issues even in traffic jams in this hot summer heat AC blasting..

Just bought the truck 7 months ago never had cause to heck under the rad cap always just looked at the overflow and it seemed fine.

Comments/Thoughts ?

both of my VQ40 engines in PF and Frontier seem to do that occasionally.

I just drained and filled the PF and replaced the thermostat; looked like a slow leak was occuring around the hose to thermostat.

The Frontier rad was low on coolant last weekend; took about a quart to bring it back to full.

dawg:

thanks for the reply.
It passed a pressure test today.. still I put on new radiator cap just in case..
Wiped the engine bay nice and lean to spot any leaks.