Our summer had some wicked heat earlier, and I had to resort to turning on the a/c in the xB quite a bit. But the temperatures have moderated lately, and when I bopped down to Cottage Grove on the I-5 the other day, there was no need, especially since the white xBox with its vertical windows stays relatively cool.
But when I hit the freeway and rolled up the windows, the air coming out of the vents was decidedly warmer than the outside air. of course it is, as the vent air goes through the blend box which includes the heater core. Then I remembered that I hadn’t flipped the valve I put on the heater hose a few years back.
I did that in Cottage Grove, and the difference on the way back was very significant. I was comfortable even though it was around 80 degrees. Of course our air is very dry, so that alone makes a difference, and my tolerance for heat is higher than average. I’m often surprised at how rarely I do turn on the a/c in the xB. And with only 103 hp, I can feel the difference quite readily when I do, and not just in the coolness of the air coming out the vents.
I did the same thing with my ’76 Honda every spring and fall, but I just disconnected the heater hose and looped the output from the engine back to the intake. The interior fan never shut off, it was always on like early 70s GM cars.
What happens when it’s foggy out and you need to clean up your windshield with the defroster?
I’d imagine the low humidity Paul mentioned makes interior condensation on the windshield a rare occurrence, plus running the a/c with the moisture will pull any remaining moisture out of the air.
Ugh…meant to type “…running the a/c with the defroster…”
Obviously I hadn’t had enough coffee when I made that post!
As BuzzDog said: out here that’s never an issue in the summer. And if it was, it would take ten seconds to stop, pop the hood, flip the valve, close the hood, and…
Is this why ‘vent’ never provides air at the outdoor temp in modern cars? Didn’t know it would be so simple to fix. Thought it was just a matter of other design factors in cars that were made assuming they’d always be A/C’d.
Some vehicles used to have a valve in the heater hose to control the flow. I myself curse the manufacturers for dropping the ball on this. Just the natural flow of cool air with out a fan pushing it thru.
Most old time cars, up to the 1960’s, directed outside air from the cowl vent down into the kick panels. It never passed through the heater box. You also had the “wind wings”, the vent windows, which just directed a blast of outside air into the car’s interior. A/C was still the anomaly, and the fresh air system wasn’t integrated with the a/c system.
Once A/C became more frequently ordered, it was integrated into the ventilation system. It’s been my experience that later model cars with inoperative a/c are awful in hot weather. The air through the vent position is limited and warm, lowering the windows doesn’t vent the interior very well, and of course there aren’t any vent windows. These cars also have smaller roofs with curving side glass that doesn’t do much to shade the passengers from the bright sunlight.
It’s similar to new houses with a/c that are built to be energy efficient. The added insulation is a plus, but they usually have limited opening windows and often can’t be adequately cooled off and ventilated without using the air conditioning. Paul’s idea is a good one.
Yes heater and ventilation are separate systems on my 66 Hillman and both work just fine plus it has quarter vent windows in the front for positive air flow.
What Jose said. Every car I owned that was built up to and including my 71 Scamp had fabulous fresh air ventilation. Every one built later (in the age of common a/c) had pitiful fresh air ventilation that was useless in all but the rarest conditions because of the heater box radiating into it.
That valve idea is brilliant!!!!
My 1963 Vauxhall had quarter lights back and front with locking swing latches for custom venting choices. I installed a in line tap in the heater hose with a 4 mm wire through the bulkhead to control the climate….. Ac near unknown then…
Luxury was the canvas waterbag suspended out on front.
Yup, valves like this can be a wise addition. I put one on my truck to try to make the A/C work a little better (but it was still trying in vain to cool an uninsulated solar oven on wheels). There are advantages to the blend-air system that keeps the heater core live all the time…in three seasons, all but Summer.
I’m surprised that, up until your post, no one had yet mentioned that doing this improves the performance of the a/c. I had a neighbor who did it for this very reason.
You should already have a heater control valve that does that automatically.
Many vehicles don’t have a heater control valve, and I think the xB is one of them. A sizeable percentage of those vehicles that do have such a valve, close it only when “Max AC” (+recirc) is selected.
Wow I did some more googling and I’m seeing that major complaint in the scion community now. That’s crazy, I hope Toyota just cheaped out on a valve and didn’t design the cooling system around having that heater core capacity.
Those old Dodges come with a nifty four nipple hot water valve that when closed re routes the hot coolant back to the engine making the AC work so much better .
My old Mercedes has a split heater core with two inlet hot water valves, even when they’re turned off heat radiates into the heater core via the one valved return hose…
Many cars made since the 1980’s use the heater core as part of the cooling system and simply dump the unwanted hot air out when the heater control is “off” .
I hate this as the heater core radiates heat terribly .
-Nate