I just did this and you are 100% what should be simple is absolutely rediculas. Took me hours and yes black and blue. I am a big guy but wish I had small hands for this job. Okay so what worked for me. First I was able to use a 10mm box wretch just to loosen. Then I used a 10mm box ratchet wrench with a swivel head. It didn’t quite fit over the bolts but once lossened I was able to push onto the top of the bolt and ratchet the rest of the way. But as stated it is tight so I was only able to ratchet maybe 10 degrees at a time so it took a while to get it off. As I note everyone state the bolt on the bolt is the hardest but I found the one at the back the most challenging. Good news is it had the orginal orange seals at 145,000 that means next change would be 290,000 should be years from now, so for that reason I see. No sense in changing it to a more accessible location. I did use original GM seals which are now black, do not see any sense in trying to save money on a part this difficult to replace. Hope this help someone
I had a 2006 Chevy HHR 2.4 with the heat exchanger(oil cooler) on it and I was able to find an adapter that allowed me to replace the heat exchanger with a conventional oil cooler. It is fully documented on this site: chevyhhr.net and just do a search in the form for oil cooler . Also if you do a goggle search you can find some still pictures I took of the process. I since sold the car (2 years ago) but I will post a video, as it seems more people are having this issue now.
Thanks for your input! I've still got this car as a daily. I'll definitely check out the link and grab that adaptor. Send me the link when you upload the video. Thanks again!