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!

No expert here, but having just done extension a/c work on my 85(talked to alot of a/c experts)

1. No, but. Your car is 22yrs,,so yes after time
2. All you mentioned.
3. Low ref, 1st culprit. Orifice, yes. When is the last time, if ever? Pulled your grill off and garden hose rinsed off all the bugs both on condensor and radiator?

I posted before. Got new compressor, receiver/dryer, o-rings and oil for $190 shipped.(and the guy gives tech support 8am-8pm 7days, he's in Texas) Replace high side line last summer, figured with all this new, replaced the low side line. My compressor didn't eat itself up, the field coil went bad. Also saw a small leak compressor bearing seal. I converted to R134 about 10yrs ago.
--
Post Back. That's whats makes this forum work.