AC has suddenly developed massive leak, planning full rebuild

[anthrax323]

Gotcha. I take it you bought OEM evaporator cores? The dealership told me that theirs come with the foam pre-installed, whereas most aftermarket ones do not (like mine - it is completely bare).

Well, I finally cracked that bad boy open... I don't see what the big deal was.

:wierd:

For sale I have one mint-condition evaporator core:

This is gonna be some fun clean-up.

One thing I noticed is that the face of the evaporator has a pre-filter of sorts (a thin sheet of open-cell foam that is held in place by some plastic pieces). The dealer said there's no reason to re-use it, as it'll eventually disintegrate and blow out through the vents... I somehow think this may be a bit short-sighted, as it must be there for a reason.

Is it meant to trap dust before it reaches the fins of the evap, or is it meant to be a condensation magnet/collector of sorts to encourage condensation to drip down and away from the evaporator? Did you ever re-use this foam?

 

[UNCC_99XJ]

Nope, the evaps we put in were aftermarket from Advance, as I was selling them at the time

The dealer is absolutely correct about the foam. In fact, i'm surprised it hasn't blown out already. All the ones I see go bad, the first sign is the foam starts shooting out at you when you turn the blower on. The two i've replaced both did that. Mine did it as well, followed shortly by no AC all of a sudden one day, but i'm still in the "recharge it before I go on a trip" phase lol.

I'm not entirely sure what it's there for to be quite honest. I always thought some sort of "blanket" for it. Can't see it trapping dust or anything. That's what cabin air filters are for (which we don't have anyways).

 

[anthrax323]

Sweet deal, thanks for the info man - I bought mine through RockAuto, so I went super-cheap with it... Probably why it doesn't have the foam.

I also just realized my heater core is 100% aluminum (not copper) - is this a good or bad thing? I remember dealing with an aluminum engine in the past (an old Ferrari 206 in a Fiat Dino) on which I had to periodically replace a sacrificial anode in the coolant tank to prevent corrosion due to the presence of aluminum and copper in the same system. Should I seek out a copper one?

Also, I found this stray part upon going to put the new heater core in:

I can't for the life of me figure out where the hell it came from, or where it goes - it was loose in the lower half of the clamshell right beside the old heater core (I very well may have dislodged it during disassembly). Any ideas?

 

[UNCC_99XJ]

Interesting you have an aluminum heater core. The ones i've put in from the local parts houses were copper...

As for that piece, I think maybe it goes across the top of both the heater core and evaporator? Kinda like a brace. Been a year or since I last had one of these open, so i'm having a hard time recalling if there was a brace on top or not. Another possibility is maybe that piece sits on the bottom, then either the core or evap sit on top of that...but I don't recall there being anything there.

 

[anthrax323]

Yeah, I'm perplexed. I've seen a bunch of photos of these HVAC boxes and not once have I seen this part. I can safely say it was not beneath the evaporator (as it was bone dry and clean when I found it), but can't seem to find a logical orientation for it elsewhere...

One peculiar thing about it is the wire/vacuum line clip on top of the piece (top left corner as oriented in the pic above). This leads me to believe it's an external piece, which may have fallen in through the defrost/windshield vent on top of the box while the unit was being removed (as it was somewhat dragged out from under the dash).

Think this is a logical assumption to make?

 

[ktwalker01]

sorry never mind..

Don't break your clock spring!

 

[UNCC_99XJ]

Going on that theory, is the defrost door still attached? It would be the one that sits behind where the radio would be and controls whether air goes to the defroster or the front vents.

 

[anthrax323]

Yep, sure is. All doors are in place - nothing appears to be missing at all.

Thus far, I've had 2 major headaches:

1) I broke those f@#$ing tabs off the housing in my haste to open it. I saw them, I made a mental note to remove them... And I broke them. I really hope this doesn't cause any problems.

2) Every single damn heater core I've tried does not fit. The Spectra Premium part has a welded-on bracket that is in the wrong position (off by over 1/2", so the external screw can't reach it), and the inlet/outlet pipes are bent incorrectly. Everyone around here carries Spectra as well, except for Advance (whose copper core was even further off) and CarQuest (whose part is made by the same company as Advance's, but with a different part number - going to go look at it when it gets in at 2).

God dammit.

 

[UNCC_99XJ]

Yup, broke the tabs too. You'll be fine.

And yup, I do recall the aftermarket heater cores being a VERY tight fit, but we were able to get the Advance ones to work.

 

[anthrax323]

Thanks man - glad to know the tabs are non-critical (I pondered putting a small line of RTV there for the sake of caution, but feared the problems it might create in the event of disassembly in the future).

What sucks is that the Advance one (Ready-Aire/Vista-Pro) was beyond a tight fit - it was larger than the stock one (not by much, but noticeably), had no foam surround on it, and the pipes were about 3" too long. I looked at ways to bend them to make it work, but there was absolutely no way... The Spectra Premium unit I received from RockAuto has a far better chance.

My 2nd-to-last local option should be arriving at CarQuest soon, and I'll just be taking the lower half of the HVAC box with me to check fitment there. Given that the vehicle has 171k on it and I have no idea when the heater core was last replaced, I really want to make sure I get it done while already balls-deep in this whole mess.

 

[UNCC_99XJ]

Without a doubt. In all honesty, the factory heater cores are of about the same quality as the evaps. It's usually one or the other that fails first, but i've seen more evaps go first than I have heater cores.

Anybody who doesn't replace both while there in there is a moron lol.

 

[anthrax323]

Yeah, well... I'm about to be a moron, lol.

I've tried 6 different heater cores today (yes, 6) - all of them are bent incorrectly and will not fit without extensive re-working. I've exhausted every resource aside from Napa Auto Parts, and I just called them only to find that they, too, carry the Spectra part.

This is f'n insane. I can't believe that a part used by so many vehicles (XJs and TJs to boot) doesn't freaking fit. Every user review I've found on Spectra part #93024 (the aluminum one I have) basically says that (A) it's bent incorrectly, and (B) it performs horribly compared to the copper unit.

I'm so fed up with this shit that I'm just going to re-use the old one. The compressor about to be replaced has a manufacture date of 2005, so the system has been re-done in some capacity already. I'm just going to cross my fingers and hope for the best.

The heater core I removed appears to be good, though - I see *very* mild surface oxidation where the vanes meet the end cap opposite the inlet/outlet pipes (white-ish in color - not green or anything), which I think could simply be due to condensation from the evaporator... In any case, if a leak does develop, I'll be living in south Texas in the near future - I'll just clamp off the heater hoses and call it a day.

 

[UNCC_99XJ]

Tried the dealership?

 

[anthrax323]

Yep. $472 for a heater core.

 

[UNCC_99XJ]

Holy hell!!!

Yeah, screw that!

 

[ktwalker01]

Without a doubt. In all honesty, the factory heater cores are of about the same quality as the evaps. It's usually one or the other that fails first, but i've seen more evaps go first than I have heater cores.

Anybody who doesn't replace both while there in there is a moron lol.

:gee:

 

[anthrax323]

Good news... I've finally completed the replacement of all the engine bay components, put a vacuum on the system (28 inHg), and 30 min later it hasn't lost a single bit... Seems like things are finally starting to work out as they should.

Next steps involve reassembly of the interior. Woo!

 

[montanaman]

Did you ever figure out where that piece goes?

 

[anthrax323]

Unfortunately not - haven't put the dash back together yet, but I'm still looking into it.

 

[montanaman]

A lot of times, it becomes clear as you are putting it all back together again. Best of luck. And you still decided to go with the original heater core?