I had a job to change the air conditioning compressor on a 2002 Toyota Avalon. This was a good customer and I wanted to do the job properly. At first the A/C compressor removal and replacement job looked pretty straight forward. I found out later that this was not the case. The problem was that Toyota did a terrible design job of mounting the A/C compressor. Four bolts held the compressor on the engine. The two top bolts connected to the block. The two bottom bolts connected to the oil pan. The oil pan assembly is a two piece setup. The bottom piece is the actual oil pan. However, this bottom oil pan bolts onto a middle piece which then bolts to the block. This middle piece is made of aluminum. And this is the problem. The two bottom bolts which braced the A/C compressor to the engine connected to this middle oil pan. The bolts are steel and the middle oil pan is aluminum. Whenever you have steel bolts threading into aluminum there is a big chance for problems. Especially when the assembly is exposed to heat and corrosion. The bolts over time can easily freeze under these conditions. My A/C compressor replacement job on the Toyota Avalon had this exact problem. The two bottom bolts were frozen into the middle oil pan. I bought another used middle oil pan from a wrecking yard and installed it. However, when I tried to install the new A/C compressor, once again I had problems with the steel bolts in this middle oil pan. The aluminum threads on the oil pan stripped. I ended up having to helicoil the two holes in the oil pan I just bought. Steel bolts in aluminum threads is a BAD idea. The A/C compressor job turned out to be a major pain. Toyota did a terrible job of designing the mounting setup for the A/C compressor on this V6 engine on this 2002 Avalon.