Heater Core replacement - Can I just cut the fire wall?

[mx597turbo]

The heater core went on my '91 n/a. I'm not going to tear the dash out, the car isn't worth the time. Has anyone ever just cut the firewall and changed the heater core that way? Maybe I'll be the first? I have seen this done on other cars before, but I don't know about clearance issues with the Jetta. Otherwise, I'll just bypass it.

[the caveman]

If you don't have AC ,even if you've never done it before , it will take less than 4 hours tops. Even better if you're motor isn't turbo'd

[the caveman]

The dash doen't have to come out, just the center console and other center dash bits.

[jtanguay]

caveman helped me with some good advice on how to replace mine

check out my thread here.

even if you have a/c, you can do it without taking the whole assembly out, but you need to be very flexible. it's hard to make out from my pics, but there are two clips holding the heater box to the a/c box in the back and a few in the front. some mechanic told me to try that route, but i did try and couldn't get it because its so cramped. so i just yanked out the whole assembly and voila! it takes a lot of man handling to wiggle that thing out so be patient and don't ram things too hard 

i'm not even sure if cutting the firewall will be much help...

[GEE-BEE]

Replace the hoses with silicone type while your there..

GB

[burn_your_money]

You'll spend more time welding the hole in the firewall then you would doing it properly. And if you don't weld the hole up you'll spend more time waking up in the ditch wondering why you keep falling asleep at the wheel.

[Powered by Spearco]

Yes! Get the torch out with the "rosebud tip" on it. Some chisles and hammers and go for it  .
Just kidding.
Bypass the heater core, buy an pwr. inverter and plug in an AC heater from that,  .

[mx597turbo]

Bypass the heater core, buy an pwr. inverter and plug in an AC heater from that

That's exactly what I was thinking. Getting this whole setup on ebay is equal to the cost of a heater core from Autozone, but MUCH easier.

[Powered by Spearco]

Good. Get some pics of it when its all done. We'd like to see them.

[Vincent Waldon]

Just make sure you do the math before you invest:

Amps = watts / volts

If the inverter is perfectly efficient, even a wimpy 400W heater is going to draw 400/12 or 33 amps from your alternator.

Since the inverter is probably only 80% efficient at best, you're looking at 33 X 1.2 or 40 amps.

This is why you can't run block heaters off an inverter and battery... at least not for long.  


FWIW: the heater core is really not that bad... a reasonable job for a Saturday with a beverage break or two. 

[Powered by Spearco]

Then take out the passenger seat and build a fire  .

[Vincent Waldon]

Getting just a tiny bit off topic, but some models of the 2010 TDIs have a 1000W 12V heater core in front of the traditional coolant core:



The wiring to it is as thick as your finger and it's protected by a 100A fuse.

Guys that have 'em report that you do get instant heat, but it's still only enough to defrost the windows and start to take the chill off... the real heat happens once the engine warms up.

[truckoSaurus08]

taking out the dash is no big deal. Theres a lot of screws and pieces but if you can do a puzzle, then you can change a heater core. If I were to do mine again, it would probably take me 2-3 hours. 4-5 for your first time maybe.

[janb]

no need to remove dash (I've done many a2's w/o), just slide back / remove console (4 screws?)

just don't forget the 3 screws for heater box accessed from engine side of firewall. 2 about mid way op the wall and horizontal, and one lower (IIRC)

Take a good look at your 'blend door' while you have it apart, and replace the foam if it is crumbling.

Check your VIN, I don't know about '91, but I have gotten FREE heater core installs on safety recall for early A2's.

[SolarSteve]

Just make sure you do the math before you invest:

Amps = watts / volts

If the inverter is perfectly efficient, even a wimpy 400W heater is going to draw 400/12 or 33 amps from your alternator.

Since the inverter is probably only 80% efficient at best, you're looking at 33 X 1.2 or 40 amps.

This is why you can't run block heaters off an inverter and battery... at least not for long.  

I actually built a setup to do just that...  It didn't really work, but it was a neat project.