No Heat - Heat

[jsfbmw]

So here's a curiosity. Why was there a no-heat condition? Was a gorgeous day in NJ and was driving on interstate yesterday evening, cruise set at 68. Had sunroof and windows open. It was glorious.

Got a little chilly and raised temp to 80 and fan on almost max. Had dash and footwell vents selected for airflow. There was no heat.

Push Auto but nothing changed. Went back to manual and still no heat.

Got off interstate and driving around 50 on local road (under limit) with temp still at 80 and fan almost max. Now the heat comes on.

Did the car know it was useless to turn the heat on earlier since there was wonderful airflow through the car? When the speed dropped the heat then kicked in.

Anyone offer reason why this happened? Otherwise, car has been perfect.

[Washburn]

Just curious - (perhaps the answer is obvious) - when you 1st turned the heat on, was it still with windows open or closed?

[zj96sc]

make sure your cooling system is bled.

[nike001]

Was the dial in the middle set to warm?

Was the snowflake on the HVAC still on?

[Stu]

This sounds like a classic cooling system bleeding problem. Wait for your car to cool down all the way, put the car in accessory, turn the heater on full, fan on low, then open up the coolant bleeder screw. Keep pouring in coolant til you see coolant come out. You might see little bubbles or see spurts of coolant, just let it do that for a little, pour in coolant again, and if only coolant comes out, you're good. It'll make a mess. Don't worry about it.

Once that happens, run your car until it reaches operating temperature and see if your heater is working. Then check the coolant level, siphon off some with a turkey baster if necessary.
Worst case scenario is the heater core :eeps Eff. That. Backflush it if you can fix it that way.

[jsfbmw]

Thanks to those who asked questions and offered diagnostics.

After starting the car, the temp setting was initially set at 60, fan on lowest setting, no A/C, and dial set to full blue, with windows and sunroof open.

After about 20min on the highway I raised the temp to 80, increased fan speed, and moved the dial to full red (at least I'm pretty sure I did the last thing, which if I didn't then I'm an idiot).

When I hit Auto, naturally the A/C kicked on, and fan stayed about the same. Went back to manual and turned off the A/C. No change.

I haven't tried what zj96sc suggested and Zell spelled out.

Last night, coincidentally, we had the same beautiful weather and the same trip occurred. This time I made sure to set the dial as needed, and all was fine. I checked the coolant level and it was fine.

If it happens again, I'll try the "bleeding" process. Thanks again.

[SoCalZman]

Was the dial in the middle set to warm?



It still cracks me up that in addition to the console controls, we have to adjust that secondary dial on the vents. When I put the temp at 80 I dont think I would mind having 80 on the floor AND upper vents. But in my car at least the upper vents seem to be totally independent of whatever temp I put on the screen. I need to put it to warm if I want warm everywhere.

Zilly German Logic

[Washburn]

I don't think it's silly at all -
it sort of enables you to 'customize' climate zones - even on a cold day, some people don't like getting blasted with heat in their FACE! but they DO like toasty/warm FEET ! The middle dial enables you to do just that, IMO! Driving with heat on your FACE on a 6-7 hr drive can really make your eyes irritated and and tired/sleepy - but with the middle dial, i can get warm feet BUT keep the face/upper area less hot/cool (really whatever temp you want) as it suits me, so I can remain alert/fresh.

[BCS_ZHP]

OP - if this happens again, it could be indicating a thermostat that is getting intermittently stuck and not allowing coolant to get hot so heater core is trying to transfer ambient temperature. I've seen this condition once and a new thermostat solve the problem.

[llll1l1ll]

I'm agreeing with the thermostat.

On a side note, what advantage does that blue/red dial have in the summer with the a/c?

[echo46]

I'm also thinking thermostat or air in system.

[jsfbmw]

Hi All. Figured I should give an update on what I experienced and subsequent observations. Sheepishly, I think I have to conclude that originally I neglected to dial the dash control to full red, and that I was an idiot for a short period of time.

There have been numerous repeats of the weather condition (a great week in NJ), having everything open and set to low-temp, and then later cranking up the heat. Each time (with dial on red) there was plentiful heat. I surmise that since it was dark the initial time, I didn't notice to double-check the dial setting. If the no-heat happens again, I'll you know. Thanks again for everyone's comments.