Heater core swap in 2003 Legacy advice wanted

[moosens]

Have a small leak somewhere and my mind is thinking ahead , maybe overthinking. But for reference I’d like to see that someone else has done a heater core swap in a 2000-04 Legacy and hopefully learn from them. 
 

Car has around 285k I think but the engine only 124k 

Be assured the car doesn’t need headgaskets , thermostat, water pump. All just done.

But I do smell a tinge of coolant inside mostly. But have to say I’m also smelling it outside a bit upon exiting the car after stopping somewhere. 

So rather than diagnose here please just let me know about your core swap experience. I’ll be sticking my nose under and around the car later. If there’s an obvious leak I’ll be sure to post back. 
 

Ok so you may have seen me ripping apart one of these species (00-04 Legacy) this past summer. Yes , I had attempted to take out the heater unit but at this time I can’t even recall completing that task as the car had to go at that point and I was scrambling around hoping I could snag the unit but I’m thinking that didn’t happen. What I do recall was that the dash was a little more tricky than I’m used to. And the heater housing was a word I’m failing to come up with. ClusterFahck of 10mm bolts or nuts. That’s a fair description. 
 

Did the search and it didn’t help. Thanks for any advice. 
 

 

Edited January 22, 2022 by moosens

[1 Lucky Texan]

check underhood along the plastic tank - to - metal core attachment. It's a common leak point. You could get a pressure testing kit from a parts store on loan to help too.

Be aware, many folks have slowed/stopped minor leaks with the Subaru Coolant Conditioner.

 

I'd want to make darn sure the heater core had to come out before tackling that job.

 

(sry to hi-jack with no info on the swap itself)

Edited January 22, 2022 by 1 Lucky Texan

[forester2002s]

I know that you suspect the heater-core, but...

Could it be a hair-line crack in the plastic header of the main radiator? Such a crack is difficult to spot, but will let a fine spray of hot coolant escape into the engine compartment.

EDIT: Just seen Texan's (almost simultaneous) post.

Edited January 22, 2022 by forester2002s

[GeneralDisorder]

It's a job for sure. My experienced tech's can do one in about 6 hours give or take. Lots of plastic and hidden fasteners. 

There's not really a good way to describe how to do it - you just have to start taking it apart. You will have to discharge and recharge the AC - that is not optional to remove the HVAC box. 

I would recommend a pressure test of the system first. Test at 20 psi or so to push coolant out of any pinhole leaks or tiny cracks faster than it would at operating pressure. 

GD

Edited January 22, 2022 by GeneralDisorder

[idosubaru]

If I had to do this I’d look into cutting the metal pipes or core access area and to avoid pulling the dash  

If it was a rust bucket good for two years or less I’d consider a bottle of subarus coolant conditioner but maybe a bad option if the engine heating/cooling are suspect. Maybe to help someone limp it to summer.

Yes I know you said no diagnosis and this will irritate you, and yet this probably isn’t the heater core.

[el_freddo]

Have you poked around the coolant crossover pipe area? If the O rings weren’t replaced with the HG job they can be old enough to weep enough coolant to make the smell. 

Otherwise it’s dash out for a heater core swap. I didn’t know about the AC discharge requirement as mentioned by GD. 

Do a search online for a turbo conversion job as the dash must come out to swap the wiring loom. Also exploded parts diagrams can be good to locate the various screws etc. The dashboard should come out as an assembly reverse of how it gets put in at the factory. 

Cheers 

Bennie

[moosens]

Thanks everyone! 
 

When I had that parts car this past summer I got to the point that GD pointed out. I was close , but the car had to go and I had the priority of completing the daily driver so the hauler showed up before I could remove the unit. But man it was in there good with all the fasteners and plastic. No where near as easy as an old school Subaru. 
 

Thanks also for what I asked you not to bother replying with , not being a wiseass , seriously I will look around today while it’s not so cold. 
 

The heat works so I’m not about to rip apart the car. 
 

I can see from my parts car experience that it’s got to be easily as GD stated a six hour job. So for me or many of you also you’d have to double that time. Folks like myself just don’t have the proper space or amount of time to knock it out in one shot.

And there’s always more Subarus coming along. Smile ! 
 

 

 

[lmdew]

If I have not done the job before, I always like to hit the self serve junk yards and pull the part there.  It's a great learning experience and you don't have to worry about breaking something you need.  You've already done that with the car you parted out.

[moosens]

Fortunately this seems like I jumped the gun. Must have been some residual coolant from the previous work that was burning off. No real heater core issue spotted at this time. Still get a very slight smell of coolant occasionally so maybe that heater core has a tiny leak but as of this time I have heat and I’m not smelling coolant with very little exception. And who knows maybe it’s just psychological. 
 

That’s it. Now to bump up the other issue , an honest one.