Loss of Heat

95greensvx · #1 01-21-2009, 05:06 AM

I am assuming that my heater core went bad but hoping it's something much easier. My 92 sat for a few weeks before I was able to acquire the small part I need to fix the shifter assembly. I started it up, let it warm up and everything worked fine, blew out warm heat and all was well. I then drove down to forked river, new jersey for my work for this week. It was a 4 hour drive and the heat worked the entire way down. The next morning, yesterday, when I got up and warmed up the car the heat just never decided to work. Is there anything I could look for to diagnose the problem or does it sound like a heater core malfunction? Thanks in advance.

dcarrb · #2 01-21-2009, 06:04 AM

The only way a heater core could malfunction would be if it were leaking, and even then you'd still have some heat. Or it could conceivably be clogged. More likely there's a problem with the mechanism(s) that control airflow through the core.

Did you try raising the temperature setting to see if you get heat at any point? One of mine starts out fine but the heat wanes the longer I drive. On trips of an hour+ I have to continually bump-up the thermostat to stay comfortable.

dcb

paulmeisterpk · #3 01-21-2009, 09:22 AM

Mine did this last year, the small bolts that were holding the servo that controls the air flow through the core were missing, so the motor itself was spinning instead of opening the door to let air flow. It is located under the dash on the passenger side towards the center of the car. Something to check out before going too far.

95greensvx · #4 01-21-2009, 10:13 AM

I tried fluctuating the settings on the instrument panel and it still continues to blow out cold air. I will take a look and see if those screws happened to come loose.

svxistentialist · #5 01-21-2009, 12:33 PM

Just as a precaution you should pull the codes from the aircon, just in case it is an electrical fault with one of the door motors or something.

You can download the code reading method in a folder http://www.subaru-svx.net/photos/user.php?How-To|14263
here. It is on a Word document.

If it does not show a code then it is probably all right electrically, and you need to see why hot water is not getting to the core.

Joe

kwren · #6 01-21-2009, 01:34 PM

sorry missed some earlier information

nothing

Keith

95greensvx · #7 01-21-2009, 01:58 PM

I felt the lines heading into the heater core from the engine bay and they feel warm, not hot but warm so now I don't know. I will examine underneath the dashboard as soon as i can to see if I can notice anything not normal.

95greensvx · #8 03-15-2009, 08:29 PM

My apologies for not replying sooner. I am going to try and flush the system again for a good amount of time but my question is I checked for any electrical issues and it came up with code 15, does anyone know exactly what this is and where it is located? Thanks.

Crazy_pilot · #9 03-15-2009, 09:12 PM

One thing you can do for the flush is to unplug the heater core hoses from the back of the engine (leave them connected to the core), flush it with water, drain it as best you can, then hold both hoses up and fill the heater core/hoses with CLR cleaner. Let it sit for a good long time, then drain and flush that out really well. You'd be amazed the sort of gunk that will get out of a heater system.

ensteele · #10 03-15-2009, 10:30 PM

The Polo Green that I just bought has the same problem. I will try codes first, then a flush. If anybody finds something different, please post here so we can see what your solution was. Thanks

SoCal LS-L · #11 03-15-2009, 10:55 PM

If you do decide to flush the heater core I would really consider just using pure water and not a flush detergent.... the reason being is the removal of internal deposits of a 17+ year old heater core has the tendency to create leaks in the hose connections. And on the SVX a heater core leak is horrible news

The heater system is pretty straightforward as far as coolant circulation goes.... so id agree with previous posts suspecting the internal air doors in the HVAC system.

95greensvx · #12 03-18-2009, 06:18 AM

I tried flushing the heater core again and am still having the same problem. One thing that seems odd is that when I turn the heat on at max flow it is warm initially for a few seconds then goes right to cold. I have code 15 coming up when I check the codes and I do not know exactly what code 15 is, anyone know what this is and where it is located?

svxistentialist · #13 03-18-2009, 07:04 AM

Quote:

Originally Posted by 95greensvx

I tried flushing the heater core again and am still having the same problem. One thing that seems odd is that when I turn the heat on at max flow it is warm initially for a few seconds then goes right to cold. I have code 15 coming up when I check the codes and I do not know exactly what code 15 is, anyone know what this is and where it is located?

Code 15 of the aircon diagnostic routine means the refrigerant sensor circuit is inoperative or shorted out.

Check the system details here: http://www.subaru-svx.net/photos/files/How-To/14349.pdf

Assuming it is a bad sensor I would consider this good news. At least you know what is the problem and a new sensor should fix it.

Joe

radarwhiz · #14 03-19-2009, 02:45 AM

Quote:

Originally Posted by svxistentialist

Code 15 of the aircon diagnostic routine means the refrigerant sensor circuit is inoperative or shorted out.

Check the system details here: http://www.subaru-svx.net/photos/files/How-To/14349.pdf

Assuming it is a bad sensor I would consider this good news. At least you know what is the problem and a new sensor should fix it.

Joe

I've been following this thread cause I'm having a similar problem. The how-to link here says it's for '95-96, is it the same for '94 too?

svxistentialist · #15 03-19-2009, 04:06 AM

Quote:

Originally Posted by radarwhiz

I've been following this thread cause I'm having a similar problem. The how-to link here says it's for '95-96, is it the same for '94 too?

Elazar my cars have the Japanese all-automatic climate control version, rather than the "button" model on the US cars.

Just the same, the underlying system for heating/cooling is fundamentally the same for all SVXes. In other words the fault codes and the parts numbers for all models will be the same, with the obvious difference that the control module is more sophisticated in the Euro/Japanese cars.

In answer to your question if you have pulled Code 15 from the aircon diagnostics on your '94, it will be the same thing causing the problem, either the refrigerant temp sensor or the wiring to it.
[edit] or possibly the auto amplifier if both above check OK. Scroll down and read the troubleshooting for Code 15 [/edit]

Joe