This past weekend, my Impreza was working great, no issues. When i was leaving for work today, my windshield was fogged up, so I turned on the defroster. The fogginess started to disappear, but then my entire windshield fogged up, as did my side windows. I stopped to wipe everything manually and continued on my way. A few miles later, the windshield started to fog up again, so I tried the defroster and it worked pretty well this time, although I could smell that sweet antifreeze odor. When I switched the selector to vent, I was met with a blast of mist/steam from all (4) dash vents. I shut the HVAC down and rolled my windows down, all while still witnessing residual steam/mist from the vents.

 

The engine temp gauge remained fine, no overheating. Engine runs fine. A/C blows super cold, as it always has. When I switch to heat, I get a nice blast of heat from the vents. No coolant on the carpet inside the car or drips anywhere. Does this sound like my heater core failed? Coming home, I had the air on and could get a very faint antifreeze scent, but nothing huge. I've seen what's involved replacing the heater core and not looking forward to doing it if I have to. Thoughts? Thanks.

Edited June 17, 201411 yr by tbolt1003

Sorry, 1995 Impreza wagon, 2.2 auto, 128,000 miles

Yea, sure sounds like a bad heater core to me, but maybe a hose has sprung a leak to the heater core. Things like that happen on old cars. Replacing a heater core is a nasty job. The dash has to be disassembled to gain access to the heater core. I gather you may already know that.

 

There are "fixes in a bottle," to stop radiator leaks. Yea, they can and do work, but use too much, and the stop leak will somewhat plug up the heater core, so the heater won't work well in the winter. Still, I would be tempted to try one, if you don't think you have much to loose with the heater core leaking anyway.

There's a drain hose for the heater/evap core box to let water out when the evaporator defrosts. It sticks out of the firewall about halfway down on the passenger side. Make sure its clear. If it clogs the box will hold all of the water from the melting evaporator core and you'll get lots of moisture on the windows.

had to do the one in my impreza to

you could bypass it by connecting the hoses. No heat for the summer. use the time to save up/shop for new part.

I started seeing antifreeze on my passenger side floor mat. I'm not sure I'll have a lot of time to do this job. What is going rate these days to replace a heater core at a dealer or private shop? Not saying I'm not up to the challenge, as I've done timing belt, cam and crank seals, HLA replacements...just a lot of work for the heater core and really don't have the time to commit to it.

It's summer time. Put a bypass hose on the heater pipes at the engine and wait til fall.

 

Dealer labor would be a killer, especially to pull the dash out to replace the core.

Last quote I got ( 2 years ago) was $600. It's at least a 4 hour job with someone familiar with Subarus.

If not,, more.

Requires a complete dash removal and cross brace, just to get to heater box.

Torx security sockets are needed to remove the TCU from the hump.

Not a fun job, but a necessary one.

Took me a little over 3 hours  to just get the dash out. In 85 deg heat and high humidity! The adhesive that is used to locate the box, just did not want to let go in that heat.

 

O.

If you do decide to replace yourself, Beergarage has a decent write up (for a 96 Outback).  

While I'm not one to shy away from a challenge, my Impreza is my daily driver so would have to tackle this on a weekend and hope I can have it back together by Sunday night.

Edited July 1, 201411 yr by tbolt1003

Just keep track of your electrical connections. Especially the ones that are around the TCU on the hump. ( You need torx security sockets to get the bolts there). Look carefully at the fsm re: screws that secure the air bag and dash. Some are hidden. If the dash does not lift with finger pressure, you still have a bolt in there.

Don't drop the steering wheel until the last possible moment. It gets in the way. Best to have an extra pair of hands to guide the dash in and out. It's odd weight and bulky.

If you do decide to replace yourself, Beergarage has a decent write up (for a 96 Outback).  

The best comment in the above link is that Subaru starts with the heater core and then builds an entire car around it!

 ( You need torx security sockets to get the bolts there). 

 

Mr. Beergarage did the ol' vice grips workaround for those. Although counting on that method can yield variable results...