My hot maker stopped making hot...

[Visonik]

...But then, it started working again.

On my way to work yesterday, I had no heat. It wasn't even warm coming from the vents. After work, on my way home, there was heat again! It seemed to take longer than usual to blow heat, though. Maybe it just seemed like longer because I was quite frigid.

Is this a sign that my heater core is going or is it possible it's just a fluke?

Also I'm not sure that I posted this in the right area, so feel free to move it if necessary!

 

[Chris]

Did the fan still blow air, just cold air?
Or was the fan not blowing at all?

Was it overheating at the same time?

 

[injulen]

Could be as simple as you need a new thermostat but if it was a long drive you'd probably have noticed it if your thermostat didn't open and the engine started overheating.

 

[Chris]

If your thermostat is stuck closed your heat will still work, if it's stuck open you'll have a low temp on the gauge and your heat will be abysmal.

If the engine is overheating and you don't have any heat, it's almost always blown headgasket.

 

[smelt240]

My old WRX would do that when it got just a tiny bit low on coolant. Sometimes heat, sometimes not.  Id check that first, and just top it up, even if it seems like a very small amount. Worked on mine...

 

[Visonik]

It's been working normally ever since that one time.

The fans worked, it was just cold air.

The motor wasn't overheating, and it was running for over half an hour. The head gaskets and everything are new as of 12 k miles ago.

I'll check the coolant once I can.

 

[smelt240]

With all of that checking out OK, Id almost bet $$$ that its a bit low, or you have an air bubble somewhere (that was a Nissan thing, not sure if the Subarus get them as bad)

 

[skipow]

do subarus have blend doors? the blend doors on my old vw used to stick and this would happen

 

[Visonik]

With all of that checking out OK, Id almost bet $$$ that its a bit low, or you have an air bubble somewhere (that was a Nissan thing, not sure if the Subarus get them as bad)

I'd have to be leaking coolant for it to get low right? Or does it just get consumed..? As far as I can tell there is no leak, unless it's dreadfully, painfully slow.

 

[smelt240]

Our 06 WRX uses a bit, and we have a hose that seeps every now and then. (fixed now, but it used to)  It only took a VERY little bit, then it would not blow heat, same problem as my 04.

 

[Visonik]

Our 06 WRX uses a bit, and we have a hose that seeps every now and then. (fixed now, but it used to)  It only took a VERY little bit, then it would not blow heat, same problem as my 04.

Cool, good to know! I'll have to check it in the morning. Thanks!