MK4 heater core

darisd

Member
Joined
Dec 27, 2008
Location
San Diego
TDI
09 CR
oldpoopie said:
Whew. Just finished doing the heater core on a 99 jetta. Wow what a pain.
Here are a few tips. Dont forget the one large bolt holding the cross member on underneath the wiper motors. Unbolt the heater box completely, but dont disconnect the AC lines. You can pull the box away from the firewall just enough to swap out heater cores.
Label all the plugs so you know where they go during re-assembly. Even if its just a little sharpie on there.

Total time was about 8 hrs including about an hr for lunch. It would have taken much much longer had nick not been helping.

I'm hoping that I never have to do it again, so dont ask for a howto! LOL:eek:
With much thanks, I put together a complete DIY and posted it on the 'tex.

http://forums.vwvortex.com/zerothread?id=4188858

I modified your procedure, unclipping the heater box and pulling only it from the dash. It went very fast.
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
Crap! To use/abuse lyrics from Lynyrd Skynyrd ("That Smell"): "Ooh that smell"...

Wife's car is signaling me to commit a chunk of time to replace the heater core.:mad:

There seems to be a bit of confusion as to how to know whether you have a split box or not. This car is a 2000 and has the rotary/manual dials. Can I expect this to be a split box? From my reading it seems that a split box is easier to deal with- please correct me if I'm wrong.

It's suggested that it's possible to replace the heater core w/o having to pull the box completely out. Assuming that this is the case, how hard is it to do this vs yanking the box (if a split box makes a difference here please let me know)? If one were to not yank the box (or half of it) out can one determine whether the blend door needs to be repaired? Would I be safe in assuming that one would have to yank the box in order to redo the blend door?

BTW - Ordered a new heater core (and gasket) from http://www.jimellisvwparts.com. $188 with the gasket and with shipping ($24- ouch!).
 

mrrhtuner

Veteran Member
Joined
Mar 29, 2011
Location
London Ont Canada
TDI
2003 Jetta Wagon TDI, 2015 Passat TDI, 2015 Touareg TDI
Crap! To use/abuse lyrics from Lynyrd Skynyrd ("That Smell"): "Ooh that smell"...

Wife's car is signaling me to commit a chunk of time to replace the heater core.:mad:

There seems to be a bit of confusion as to how to know whether you have a split box or not. This car is a 2000 and has the rotary/manual dials. Can I expect this to be a split box? From my reading it seems that a split box is easier to deal with- please correct me if I'm wrong.

It's suggested that it's possible to replace the heater core w/o having to pull the box completely out. Assuming that this is the case, how hard is it to do this vs yanking the box (if a split box makes a difference here please let me know)? If one were to not yank the box (or half of it) out can one determine whether the blend door needs to be repaired? Would I be safe in assuming that one would have to yank the box in order to redo the blend door?

BTW - Ordered a new heater core (and gasket) from http://www.jimellisvwparts.com. $188 with the gasket and with shipping ($24- ouch!).


Just yank it out.

But if you do/don't..where you slide in the heater core you will be able to see one of the doors. Mine was in fair shape but I still removed all the foam and used HVAC tape to prevent ever dealing with it again.

It's not a hard job really, its just time consuming.

I just did my last weekend.
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
Another question...

Do I really have to remove the center console?

It's like you have to remove the car from the heater core!
 

mrrhtuner

Veteran Member
Joined
Mar 29, 2011
Location
London Ont Canada
TDI
2003 Jetta Wagon TDI, 2015 Passat TDI, 2015 Touareg TDI
Another question...

Do I really have to remove the center console?

It's like you have to remove the car from the heater core!

Yes, everything has to go. I mean everything. One of the worst jobs to do on a MK4.

As turbocharged said...yes.

It's not that bad as it seems. Its just hugely time consuming. If you have a good memory it's easy to assemble it all.

Example.

I started removing my cupholder/center console fairly quick. Then it was off with the glove box, Radio housing (double DIN) and then the plastic plates above the driver's knees.

Most documents state you have to remove the Double DIN radio from the housing...I didn't have to. I unscrewed the housing from the dash and just disconnected the cables for the vent/radio.

The steering wheel isn't bad at all, the airbag may give you a bit of a challenge but using small precision screw drivers I was able to remove it in literally 30 seconds.


Dash is held in place with 8-10 screws and that's it.


Once the dash is removed, you just take your time getting to the HVAC box. The job does suck to do but it's not horribly bad really. I was worried about it and couldn't shake it out of my mind until I completed the job.
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
Thanks for the tips! I'm good on steering wheel removals, having recently performed 3 of them: once on my car and twice on the wife's (replaced a used 3-spoke that I'd recently swapped in with a NOS one [also NOS in my car]).

I've also replaced a front lower console piece, so familiarity there too. Is it also the same for this job that I have to first remove the lower console rear piece and then the front?
 
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mrrhtuner

Veteran Member
Joined
Mar 29, 2011
Location
London Ont Canada
TDI
2003 Jetta Wagon TDI, 2015 Passat TDI, 2015 Touareg TDI
Thanks for the tips! I'm good on steering wheel removals, having recently performed 3 of them: once on my car and twice on the wife's (replaced a used 3-spoke that I'd recently swapped in with a NOS one [also NOS in my car]).

I've also replaced a front lower console piece, so familiarity there too. Is it also the same for this job that I have to first remove the lower console rear piece and then the front?

Yes, it all comes out as it only sits one way to make it look proper.

This is the common thread people use.

http://forums.vwvortex.com/showthread.php?4188858-DIY-MK-IV-Heater-Core-Replacement

Read it carefully and read also the sub threads in there for the dash removal and all that.


The job sucks but it's not hard.
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
Yes, it all comes out as it only sits one way to make it look proper.

This is the common thread people use.

http://forums.vwvortex.com/showthread.php?4188858-DIY-MK-IV-Heater-Core-Replacement

Read it carefully and read also the sub threads in there for the dash removal and all that.


The job sucks but it's not hard.
Yeah, been through that (will use it as a guide) as well as all the referenced links.

I'd taken some vacation days and was hoping to do other things.:( Between vehicles (just repaired the tractor the other day) and animals I just can't get a rest!:eek: (which is why I'm desperately looking for anything that can help reduce the projected 8+ hours of work)
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
Other than looking to revamp the blend doors is there anything else that's a good idea to deal with while here? I know that a newer style glovebox would be a good idea, but don't know whether it's worth spending for: current one is functioning and I believe that I know how to keep these older ones from failing; and, bigger opens up to the "bigger closet" syndrome!

I'd read of mention of possibly needing new O-rings on the heater core lines/fittings. How likely? (I think that I'd seen mention of a size and that one could find substitutes rather than having to go to the dealers- I suppose I'll poke around again for that note.)

Oh! According to the parts diagram for my car (Jim Ellis folks corrected me on my initial selection- good thing I provided my VIN! [correct core is even cheaper, though only by a few dollars]) it appears that I have a split housing. Maybe I finally get a break on something?
 

mrrhtuner

Veteran Member
Joined
Mar 29, 2011
Location
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2003 Jetta Wagon TDI, 2015 Passat TDI, 2015 Touareg TDI
Other than looking to revamp the blend doors is there anything else that's a good idea to deal with while here? I know that a newer style glovebox would be a good idea, but don't know whether it's worth spending for: current one is functioning and I believe that I know how to keep these older ones from failing; and, bigger opens up to the "bigger closet" syndrome!

I'd read of mention of possibly needing new O-rings on the heater core lines/fittings. How likely? (I think that I'd seen mention of a size and that one could find substitutes rather than having to go to the dealers- I suppose I'll poke around again for that note.)

Oh! According to the parts diagram for my car (Jim Ellis folks corrected me on my initial selection- good thing I provided my VIN! [correct core is even cheaper, though only by a few dollars]) it appears that I have a split housing. Maybe I finally get a break on something?


Don't worry about the glovebox. Don't fix something that's not broke. The glovebox you can replace anytime in the future and it does not entail all this work. You can swap the glovebox in 20 minutes if your current one failed.


Also, the Heater Core O-Rings that attach to the connector on the engine, firewall side, well I didn't replace them. They weren't leaking before so I never bothered.

You can easily replace them if needed without getting to the heater core.

The two lines run from the EGR cooler to the firewall so it's easy to get to if the o-rings need replacing.
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
I might have to delay this work. Car is committed to going to a GTG for something else, in which case I might end up bypassing the heater core for the interim. It's the wife's car, though, and I most certainly can't drag this out: her car has heated seats, mine does not- before I know it Fall will be coming and I don't want to hear about her being cold!
 
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