Heater Coil Update Again- It Didn't Work

[mikec03]

I have a 95 subaru with a leaking heater coil.  The service manual calls for the removal of the AC evaporation coil to remove the heater coil.  From the manual it's hard to see why.  Isn't it possible to slip the heater coil in without disconnecting and removing the evaporation coil?

Update 1/30/19  Alas, the Subaru stop leak would stop heater core leakage for a while, but after cooling down and reheating, it would eventually come back!  It wouldn't leak much but enough to smell it.  Maybe some product designed just for radiator leaks would work, but I'm not going to try it.  I will have the heater core replaced tomorrow.l

 

Edited January 30, 2019 by mikec03

[GeneralDisorder]

You have to pull the dash and then pull the HVAC box out of the car and split it in half. Yes this requires disconnecting the AC. It's a 10 hour job. 

GD

[mikec03]

Thanks GD.  That's what I was afraid of.

What is the most common type of failure on the coil?  Is it a pin hole or a crack or?.  What I'm wondering is whether the subaru coolant "additive" would seal it.

[GeneralDisorder]

Honestly I couldn't say. In 20 years of working on Subaru's I have changed only one heater core. They last almost forever, and once they fail the car has so little value no one wants to pay to change it. They scrap the car instead. The cost is about $1500 when you figure the labor, heater core, coolant, and hoses. It's more than your 95 is worth at this point. If you do it yourself it's not too bad, but it's an ugly job. The coolant conditioner is worth a try. 

GD

[el_freddo]

No harm in trying the additive. Worst case it still leaks and you’ve lost a couple of bucks. 

But would this give you piece of mind knowing there’s potentially a ticking time bomb waiting to do the same or worse?

The L series had plastic end tanks on their heater cores, these used to let go all the time... but I’ve not heard of an EJ core going now that I think about it. 

Cheers 

Bennie

[idosubaru]

keep in mind people criticize the additives for “clogging up the cooling system”.  I would think this happens in situations outside of designed purpose.  Coolant gets low and internally causes pockets of air, larger temp gradients and momentary localized places of excessive heat or pressure - which causes the sealant to do internally what’s its only supposed to do at a leak.  But this is actually 100% guessing, I’ve never heard anyone say anything like that, it just makes sense to me.

either way - additives have a downside  

If I was using an additive in this case I would consider being meticulous about the radiator coolant level (not just the overflow) and any other comprised parts - hoses, leaks, radiator cap, Tstat, etc - in order to prevent any conditions internally which the system (and possibly additive) wasn’t designed for. 

Edited December 15, 2018 by idosubaru

[86BRATMAN]

I've pulled the dash and heater box from several legacys of this lineage without disconnecting the evap core. It requires a bit of finesse to pull the ac lines just enough to give clearance for the box to come free. 

[mikec03]

 

Adding the the subaru conditioner stopped the leak!  It took about 1 hr of driving.  At first, turning on the heater and fan made the inside of the car look like a turkish bath.  Fog all over inside.  Today, one day after adding the conditioner, I can't see or smell anything when I turn the heater on.

That "stop leak" conditioner really works well.  I would never have believed it.  Anyway it's the goto solution for anyone who has a heater coil leak.  One poster says that the conditioner stopped a coolant leak for 30K miles.  I guess I will find out.  Thanks for all the help and information.

 

 

Edited December 16, 2018 by mikec03

[lmdew]

Great, hope it last through the WI Winter at least.

[idosubaru]

Awesome.  That’s great, thanks for reporting back. 

[GeneralDisorder]

I figured it would work. Don't forget to add another bottle every time you change the coolant. The stuff actually works really good. 

GD

[jonathan909]

That stuff works, huh?  I'll certainly try it first if there's a next time.  I didn't much enjoy the heater core replacement on my '99 Outback, and wasn't impressed that I was forced to lose the AC charge in the process.  "Serviceability" should have dictated that the heater core be removable without the evaporator having to come out too.

 

[whynot]

man I miss the days of the old ford heater core. 30 min, open door swap core close door... Now you have to tear the car apart.

[GeneralDisorder]

There is no need to design them that way. It's just lazy engineering and bean counters cutting costs. Some of the Saturn's even into the 2000's you could swap the heater core in about 15 minutes. 

My 86 Trans Am even - well into the plastic unibody era. About 2 hours total. 

Subaru of basically any era right back to the 70's is between 6 and 12 hours. Always been ridiculous. Although they are usually quite reliable. 

GD

[CNY_Dave]

I did a heater core in an AMC eagle 4WD (or was it an evaporator?). This looks worse.