[tightlynes]

Ok, I've got a bug to work out. I've got a 2003 Outback with about 118,000 miles. I've performed basically all recommended maintenance.

Here are my symptoms. After the engine gets to temp, my heater gets inconsistent. While sitting at a light, the air will often gradually cool down, sometimes feeling almost like air conditioning. Then when I start driving again, the heat comes back pretty quick. It is related to the engine not being at idle, or maybe under some sort of strain.

I recently changed the thermostat and radiator hoses. I've checked to make sure it's full of radiator fluid, and it's full to the top with a little extra in the overflow reservoir. The temp gauge holds right where it needs to be without any big temp spikes.

Any ideas? Is this sounding like a bad water pump? I've never replaced the original water pump. That's my most likely suspect, but if there's a way to verify before I start taking things apart, I'd like to do it.

Any help is appreciated.

 

[1 Lucky Texan]

what brand of t'stat

did you 'burp' the coolant system

were there ANY unusual issues before you did the work

 

[tightlynes]

I used a factory thermostat, and I burped the system. I'll have to double check I suppose, but I think I did get it burped adequately.

The only unusual issue I had before the work was my lower radiator hose was leaking and spraying fluid on the exhaust, so I replaced the hose. Since I had the system emptied out and the lower hose pulled, I figured I might as well replace the thermostat while I was at it.

 

[1 Lucky Texan]

well, you either recently did a TB or are overdue for one. If the latter, just put in a new WP with the other TB parts.

I guess you aren't loosing coolant and the fans are working?

maybe a blend door is cycling but i wouldn't know why. When the system is 'failing' perhaps you could carefully feel (or use an infrared remote thermometer to measure) the upper and lower hoses. If the t'stat is open and coolant flowing they should both be warm. Top one should be hottest. You can also use the therm. to measure a few areas of the radiator. If sections are clogged they will be cooler.

maybe someone else will have a good idea.

 

[tightlynes]

well, you either recently did a TB or are overdue for one. If the latter, just put in a new WP with the other TB parts.

WP= water pump, correct?

What does TB stand for?

I'm not losing coolant. I was because the lower hose was completely shot. That's why I replaced it. And the fans are working just fine, so I don't think that's the issue.

I'll double check this am that I burped it adequately.

 

[1 Lucky Texan]

yeah water pump

TB = timing belt

 

[tightlynes]

Ah. I did recently have the timing belt done, but they didn't do the water pump at that time.

But when I opened it up this AM, the level in the radiator was down pretty far. I thought I'd burped it adequately, but apparently I was wrong. It took probably more than a quart. That went a long way to addressing the problem. It still cools off at lights, but it at least stays warm, and doesn't feel like air conditioning now. So I've probably still got some air backed up, but I'll keep on burping it until the problem goes away.

Thanks for your help. This is a pretty important thing because my fiancé is a HUGE cold wimp and it hasn't been above 15*F for a couple of weeks now. I'm no expert in women, but I know enough to know that if she's unhappy, the unhappiness will quickly spread to me.