On Mon, 10 Jul 2017 07:48:55 -0700 (PDT), wrote:

On Saturday, July 8, 2017 at 10:49:29 AM UTC-4, Stormin' Norman wrote:
On Sat, 8 Jul 2017 07:38:02 -0700 (PDT), trader_4
wrote:

On Saturday, July 8, 2017 at 10:30:18 AM UTC-4, RonNNN wrote:
In article ,
says...

On Saturday, July 8, 2017 at 10:19:27 AM UTC-4, RonNNN wrote:
In article , says...

I don't see how any state inspection would spot a leaking heater
core,
unless it's pouring out. In warm weather, the coolant flow is off,
there would be no leaking.

Wrong.

--
RonNNN

So, you have hot water flowing through your heater core when it 80 outside and the car interior is set to 70? Must be a unique car.

There may not be flow, but there is pressure on the hoses and core, and
it *WILL* still leak.

--
RonNNN

Thinking it through more, you're right. I was thinking valve off, no flow. But you're right, the return line is still open and going back to the coolant loop, so it will leak. Probably not as much, but it would leak unless it's some unusual design that cuts off both paths.

+1

+2
the heater core is still under pressure even with no flow
m
Except in the VERY RARE application that uses a 4 hose shut off valve
---. They do exist, but I can't tell you what they were used on.