Got an A/C issue on my recently bought '99 Tahoe (5.7). While looking it over I noticed a green stain on top of the A/C compressor. Didn't think much of it until I noticed the A/C wasn't cooling as well as it should. Took another look and on top of the compressor there are two black screw caps on the front and left sides of what I assume is some type of coolant valve. (R-134a conversion maybe?) The front fitting appears to be leaking a bit under the cap. Never worked on A/C equipment before and really don't want to with all the high-pressure fittings and stuff. Easy fix or new compressor?