Howdy all. I had lousy performance from my 90 740T's A/C the other day. Turns out it was the belt turned sideways. I replaced the belt, and it's back to its usual so-so functionality.

I have a few questions. An AC primer would be helpful if someone can point me to one.

1) All systems leak a little, right? So on a long enough timeline, every AC system would stop working eventually due to leakage from normally functioning ("non-leaking") seals, yeah?

2) Contaminants. What are they? Where do they come from? Are we talking bits of seals, bits of tubes, pipes, hoses, and byproducts from oils & refrigerants? It's hard to imagine that anything much was introduced into a sealed system that's under positive pressure. Things are more likely to go out than in.

3) What's the likely cause of my poor cooling? Low refrigerant seems to be the most likely cause to me, but I can also see that it would only take a little bit of junk to block up an orifice tube.



I've got a year left in college, so I'm on a budget and AC is not a priority, but after that I may go to great lengths to get it working. For now, I'm interested in improving what I have without too much cash or time investment.

Happy bricking!