Heat exchanger pipe removal

[Dirtbag454]

Is it necessary to remove the aluminum pipes between the heat exchanger (heater core) and the heater hoses in order to slip the heat exchanger out for inspection and cleaning? I am replacing the heater hoses and the O-rings on my '00 LHD S80. The articles I have read seem to indicate that the core will slip out easily once the pipes are disconnected, but even with removing the metal flange and the rubber gasket from the firewall, I cannot gain enough clearance past the pipes to remove the core.
Does anybody know the secret?
I made the mistake of adding some stop-leak to the system when my O-rings first started to leak. Now, I am at a point that I want to pull the core and flush it. I also would like to try fitting up the O-rings and those odd horseshoe clips while I have the parts out and accessible, before I go back to Braille for reassembly.
Both pipes are "loose", that is they are wobbly in the space they occupy, but figuring out which way to turn them to slip them out is a challenge. Also, might they go out forward rather than to the back?
I'm confused. This car is a challenge at every corner.
Any and all responses are greatly appreciated.
Dave

[Dirtbag454]

I finally gave up on this part of the project, as I had done enough additional damage under the dash to keep me busy for a month of Sundays. I did get the O-rings replaced, but those presented their own challenges as well. The upper pipe popped right in to position, and I used a 90° needle-nose plier to fit the clip (new) back in place. The lower pile and O-ring were not so cooperative. After several tries and a LOT of grunting and profanity, I thought I'd try putting the O-ring in the recess, rather than on the pipe. A little slickum, and the pipe slid right in.
Project finished...well, almost finished.
I was expecting the sunroof and the windows, and a whole bunch of other stuff to not work, as I had run the battery down by leaving the doors open for too many hours, and I had to recharge it. I was prepared to do the remote-reset. I was a bit dismayed when I fired her up and I couldn't pull her out of PARK! Damn! I thought perhaps I had loaded the park pawl when I lowered her off the jack, or something like that. I even jacked the car up to unload the pawl...still wouldn't shift. Then I REMEMBERED! I had knocked a plug loose from the brake light switch when I was thrashing about in the footwell, and I hadn't plugged it back in. Problem solved.
As I mentioned on a prior thread, now the timing belt, and the ball joints, and the PCV service, and and and...