I have been going over the '81 with a fine tooth comb getting prepped for the trip to BG. In doing so I found yet another surprise! The heater line that connects to the water pump has a short section of hose then a aluminum bent tube that bends 90 degrees (twice) around and under the A/C compressor. It is attached with a clip to the lower bolt on the compressor. I removed the hoses to find that the tubing is severly corroded and had holes through under the hose. The part is not available in any of the catalogs that I have nor through Chevrolet. I'm having one made at a specialty shop and is about a week away. I don't know how many model years this tube was used on but you may want to give your C3 a close look. :eek
