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Hi,

 

I have '95 Legacy Sedan AWD 2.2. I'm wondering if everything is ok with the heater...

 

I suppose the temperature gauge needle should be horizontal when the engine is at normal running temperature, pointing to 9 o'clock. Mine points to aprrox. 8:30. That's not a big issue, but for me the heater is not producing so hot air as I'm used to. Are these two issues related to each other?

 

If we have (and usually have during winter) minus 15 Celsius or more, the heater can provide just enough warm air. But, the temp lever must be so far right as it can be. Reducing the temp setting even a little will cause the incoming air to cool down significantly. Just like some flap is not opening enough or the water is not hot enough. Is this normal? I checked the flap mechanism and it seems to operate correctly.

 

Another thing. I crawled under passenger side dash and noticed some adhesive tape mess under the heater box. I removed them (and got some garbage into my eyes), there is a rectangular opening about 5in * 0.5in. Seems like something is missing there. You can see some core and the blower resistor through the opening. There is also a lever which seems like it should hold something there.

 

Here is a picture of the heater box: http://www.rantakallio.fi/images/heater.jpg The opening is covered with a tape. The lever is just in the middle of the picture.

 

Any ideas?

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Check the coolant level at the radiator when the car is cold.  

If it looks fine, bring the car to temp and then check the heater hoses in the engine compartment, are they both hot?  If so you have coolant flow through the heat exchanger.

Temp gauge in most subarus run at the 1/2 mark.  A little below is no big deal.  Thermostat may have been changed out.  If you put a new one in, get a Subaru Thermostat.

 

I've pulled a few of the heater boxes and don't remember a cover or slot where your hole is.  I'd suspect broken plastic.  Did someone pull the AC Evap core by chance?

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Check the coolant level at the radiator when the car is cold.  

If it looks fine, bring the car to temp and then check the heater hoses in the engine compartment, are they both hot?  If so you have coolant flow through the heat exchanger.

Temp gauge in most subarus run at the 1/2 mark.  A little below is no big deal.  Thermostat may have been changed out.  If you put a new one in, get a Subaru Thermostat.

 

I've pulled a few of the heater boxes and don't remember a cover or slot where your hole is.  I'd suspect broken plastic.  Did someone pull the AC Evap core by chance?

Good advise here. my instinct says to replace the thermostat with a good one, either from Subaru, or the most expensive after market from a parts store, or on line. Cheapie thermostats don't work well in Subarus. My temp guage when fully warm is just slightly below the middle mark. As said, if your coolant level is low, then your heater will struggle to put out hot air.

 

I would be inclined to peal back the duct tape, and see what is going on behind that tape. Have a roll of duct tape available in case the tape there replaces broken plastic.

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The thermostat sounds very resonable, I will change it sooner or later. Otherwise the coolant circulation looks like and feels like normal.

 

I removed the duct tape. Here is a photo: http://www.rantakallio.fi/images/heater2.jpg, also the lever is positioned on the opening, compare to the first picture.

 

The opening is factory made, it is obvious. Nothing seems to be broken, something is just missing, but what...?

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Change the T-stat, use one from subaru, as even the most expensive aftermarket one wont be as good as subaru's.

 

http://opposedforces.com/parts/legacy/us_b11/type_7/climate/heater_system/  Thats the heater system.

 

The heater core box http://opposedforces.com/parts/legacy/us_b11/type_7/climate/heater_unit/illustration_1/

 

When you switch between fresh air and recirculate do you see a flap moving anywhere?

 

Since I can see leaves and such, drop your blower motos and vacume it out and as much as you can inside the heater box. That may help.

 

And yes your running a little cool, and a little cool on a 4 cyl can make all the difference in the amount of heat available inside the car.

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It almost looks like an opening for a cabin air filter. Strange though because these older cars didnt have that.

 

Gonna 4th or 5th the new thermostat idea. And it may be smart to back flush the heater core and bypass piping while you're changing the t stat.

The cooling systems on these are stranger than most. Coolant is always flowing through the heater core, which is part of the bypass route, even when the thermostat is closed. This bypass route is designed to keep the thermostat open in cold weather since it is on the inlet side of the water pump. It delivers hot water to the thermostat housing via the heater core.

If there is an obstruction in the heater core or bypass piping the coolant in the bypass may not be warm enough to keep the thermostat fully open in very cold weather. This causes the temperature needle to climb as coolant flow through the engine block slows due to the only partially open thermostat. This can get so bad that it actually causes overheating in some cases, because the thermostat closes completely.

Aftermarket thermostats are prone to causing trouble due to their smaller size. If it has an aftermarket, swapping for a dealer tstat and getting fresh coolant in the engine is the best way to start.

When you refill the cooling system after swapping the tstat, fill the engine block first through the upper radiator hose, re-fit the hose, then fill the radiator with the bleeder screw on the passenger side open. This prevents air locking the block and overheating from the lack of coolant.

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When you switch between fresh air and recirculate do you see a flap moving anywhere?

 

Well, I cannot see (didn't look), but I can hear something moving.

 

It almost looks like an opening for a cabin air filter. Strange though because these older cars didnt have that.

 

 

Could it be from a later model? Could a later heater box be installed in an older car?

 

Anyway, the thermostat will be changed. The extra opening in the box does not (hopefully) cause any other problems, so I'll just leave it as it is, unless someone will find out what it is...

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  • 3 weeks later...

Ok. Let the extra opening be there. The duct tape covers it properly, so there's no problem. Just being curious...

 

But, how to change the AC button bulb? I was told that it should be lit when AC is on. Finally got one warm enough day to get the AC running and noticed that AC is running ok. The button light does not work, obviously the bulb is broken.

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