Hello all, I am new to the forum and have previously posted and got wonderful responses from all of you, Thank You. My MB obsession started back in the 90's when my friend talked me into buying a 1981 240D. The car ran like a top with minimal expense and finally bit the dust,I believe it was the injector pump. Anyway my new (old) ride I am obsessing about is a 1987 420 SEL. Great shape, 129,000 miles and runs like a top. I had an MB indy repair the rear axel ,new tranny filter and fluid and repair center pod and check the timing chain and guides. They came to the conclusion that my timing chain and guides were good,we'll check it on your next oil change. My question to you'all, the AC is fully charged and not leaking(according to a different shop).I can see a couple bubbles in the sight glass when I turn on the AC and then they go away,but the AC doesn't blow real cold,it seems as thought their is some humidity in the system and I am figuring monovalve. I have one on order and am going to replace it regardless. Is this feasible? Any ideas or speculation would be greatly appreciated. You guys know what you are talking about!! Thanks.