Good news, everyone!

I successfully bypassed the heater core. I spent about $25 on heater hose, clamps, and antifreeze. I called a shop about bypassing the core before trying it on my own, and they gave me the run around, so I decided that I would bypass the core myself. No more leaks, coolant now stays at a consistent temperature between 187-199, give or take a couple of degrees.

I also bought a repair guide for my HHR. I will study up on it and change the heater core when I feel like I am more mentally prepared. I won't be needing heat for a while (thanks, Texas!)

 

Good on the bypass. I did a bypass when my heater core in my other car went - and then finally got to taking it apart and replaced the core. It was a MAJOR job, aided by my Chiltons?/Hanes? shop manual. I spread it over several days then got a major delay in getting back to it - which was a mistake, as I had forgotten how some of the stuff came apart. But it went back together in the end - and all was good.

In hindsight I should have used more labelled zip locked bags for the various fasteners that were removed, I should have used the cell phone for taking a few pictures during the disassembly.

Best of luck when you tackle the job - keep us posted on how it goes. :)

ps: be very careful when working near the airbags and follow all precautionary steps with them - and make sure you disconnect the Neg side of the battery before ripping the dash apart (including the air bags).

 

The airbags are totally disabled after the battery has been disconnected for 15 minutes. The retained power is drained by then, 15 minutes has plenty of buffer.

 

Reread the AZ directions I posted earlier, good luck, Grasshopper!

 

Those are great instructions Oldblue - I wish I had a similar set when I did the heater core replacement in my other car (a Dodge Avenger). But the autozone info is pretty sketchy - Product & HowTo Info | | | REPLACE | AutoZone.com

 

Update:

It's finally getting a little chilly outside, so I'm going to take another stab at replacing my heater core. I don't expect to finish this job in one day, but I do have a friend who is willing to give me a hand one day this week, so realistically I may be able to finish it in a day or two. I have my repair guide handy, as well as all of the tips and advice everyone here has offered, which I very much appreciate. The only thing working against me is that I don't know what certain parts of the dash are called. I can try to provide a better example when I am near my repair guide. I want to try to document everything I take apart (take photos). Weather permitting, I'm going to start tomorrow.

 

Best of luck on one nasty project. Just take your time, and don't force anything. This diagram might help a little with the dash parts. Taking pictures really helps, as well as having numerous containers you can label describing where the parts came from.

 

Thanks for the diagram! That will definitely come in handy.

 

Get some small bandages and sauve for the nicks and cuts from all that plastic and steel!

 

Making some progress, but I'm currently stuck at removing the instrument panel. Per my guide:

"Release the passenger's side airbag from the instrument panel cover by pushing in on the tabs to separate the airbag module from the trim panel."

There is no illustration to go with this and I don't see what this is referring to. And yes, the negative side of my battery is disconnected.

Edit: found the tabs...under the airbag panel. MAJOR pain to take out. The instrument panel dash is off now. I have run out of daylight, so I will continue tomorrow morning