The heater core in the brick failed spectacularly the other day (along with 56 other failures, many less spectacular). It's said to be a 10-20 hour job. Has anyone cut a hole in the firewall to replace the heater core, and then filled the hole with a patch panel with some RTV and rivets? Seems way easier with actually gained functionality. Any issues with this? The only thing I can think of is that cutting the hole won't be terribly easy.
Seriously.
I've done that for fuel pumps. I don't see why it wouldn't work, but like you said cutting the hole is gonna suck.
I considered it on a 960. I sold the car instead of fixing it.
Toyman01 wrote: I've done that for fuel pumps. I don't see why it wouldn't work, but like you said cutting the hole is gonna suck.
I am thinking of a 90 degree adapter for the Dremel and a miter bit.
whoever told you it was a 10-20 hour job is trying to scare you. I've done it in 4. it's essentially the same job as changing the fan blower.
EvanR wrote: whoever told you it was a 10-20 hour job is trying to scare you. I've done it in 4. it's essentially the same job as changing the fan blower.
http://www.vcoa.org/700-900-faq/HeaterCoreReplacement.htm
tuna55 wrote:Toyman01 wrote: I've done that for fuel pumps. I don't see why it wouldn't work, but like you said cutting the hole is gonna suck.I am thinking of a 90 degree adapter for the Dremel and a miter bit.
That would do it, it's just going to be slow. Dremels aren't known for power. Might try a air die grinder instead if you have one. HF sells them for about $12. You could get one for Christmas. 
It's been a while since doing one, but I don't remember them being any more than 6-8 hours. The thought of someone cutting up the firewall to get it out is scary. Do it right or bypass it.
Cone_Junky wrote: It's been a while since doing one, but I don't remember them being any more than 6-8 hours. The thought of someone cutting up the firewall to get it out is scary. Do it right or bypass it.
That's the question, why is it scary? There are plenty of cars with block off plates for various reasons.
It's already bypassed, but it's friggin cold.
Cutting a hole in a shear panel that is also a "firewall" just sounds bad to me. I am sure if the firewall was designed to have a hole and a plate it wouldn't be an issue. I don't see how all the work, clean-up, and repair of said hole would be any less effort then doing it properly. Besides, the hole would have to be huge to pull the complete HVAC unit out.
Cone_Junky wrote: Cutting a hole in a shear panel that is also a "firewall" just sounds bad to me. I am sure if the firewall was designed to have a hole and a plate it wouldn't be an issue. I don't see how all the work, clean-up, and repair of said hole would be any less effort then doing it properly. Besides, the hole would have to be huge to pull the complete HVAC unit out.
Just the heater core. Not the whole unit. It would be as big as the heater core.
The heater core isn't a free standing unit. It is encapsulated in the HVAC box.
We are talking about a 700, right?
Get somebody to print the volvo factory service instructions, get out a phillips and 7mm, 10 and 12 sockets, a cushion for your knees and go nuts. It flat rates at about 7 hours, I can do them in about 5, but I've been working on them for a very long time.
Cutting a hole in the firewall is likely the worst idea I've ever heard, and would make the job more difficult by a factor of about 600.
Cone_Junky wrote:
That was helpful. I did it in about 7. Hopefully the new one won't leak.
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