On Saturday, July 8, 2017 at 5:32:58 PM UTC-4, RonNNN wrote:
In article ,
says...

On Sat, 8 Jul 2017 09:30:19 -0500, 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.
There will be flow too, in MOST cars still on the road. The vast
majority do not control water flow through the heater core any more -
they just control air flow, either through or around. This is
particularly true of cars with "climate control" or automatic
temperature control / AC

Without trying to step on any toes, I retired from automotive after over
45 years in the business over three years ago. I was just pointing out
the simple fact that flow has nothing to do with whether a heater core
will leak or not. I even almost suggested T-4 ask you, since they seem to
take your word for all things relating to automotive.

--
RonNNN

IDK what all cars do, but it seems highly illogical to
try to regulate the cabin temp by having a heater core
going at full blast all the time, even when the AC is on.
The heater core is in the cabin, correct? Even if it's
not directly in the air flow, you'd still have an enormous
amount of heat generated by it in summer when the AC is
on. Why would you make the AC work harder, eating up gas
mileage when a simple valve can regulate the amount of
heat from zero to max? And I know for sure late model
BMWs use a coolant flow valve to the heater core, I've
seen it with my own two eyes.

Maybe Clare can explain why this heat from an always on
heater core isn't a problem and why it's a better design
than a circuit with a simple solenoid valve.