Started noticing a squeaking/clunking noise coming from the front passenger side while turning. After removing the front wheel I found that the rear beam of the front sub frame was completely rusted through on the passenger side at the body mount and sway bar bushing location. The driver side of the rear beam and the rest of the sub frame has little to no rust. Any rust is light surface. After doing some of my own investigation, along with some online research, it seems that the cause is the drain from the AC system. It drains directly above this sub frame location. The AC system was repaired this past summer, after not working for several years, and I assume this is what accelerated the issue.

Update from Mar 15, 2015: The cheapest I was able to find an OEM replacement for the rear beam was around $550. Although others online have stated that they could source them from junkyards for around $100-$125

My brother has done a lot of work on my car including welding the flange after it was almost rusted through. The last work he did was installing a new tailpipe. When he did this and inspected the undercarriage he and the welder who assisted him noticed two cracks in the subframe. They determined that this was caused by the fact that the air conditioner drains at this spot.

This appears to be a Honda design flaw as this is the only area where that has occurred. The Honda Accord is a good car and I'd like to continue driving it but I'm afraid that this problem could cause an accident. I believe that Honda should pay for repairs as its design flaw is causing the problem. I too have heard noises when I turned corners. So far nothing terrible has happened but I'm becoming worried about driving greater distances at high speed because if something happened it could be catastrophic for all concerned.