For those of you who still have a 99 SI with working AC, what vent temps are you getting when the ambient air is over 94 degrees F? This is assuming ac is properly charged and everything is working as it should. My 97 DX coupe would get to 42 degrees vent temp but my 99 SI cant do as good .

 

I don't have a 99 SI, but every car my dad and I have recharged in the shop got down to around 40. That's with a professional system, not cans from the parts store.

 

You may need to clean the condenser and/or properly charge the system (by weight). Following the AC performance test outlined in the shop manual can help isolate the problem. Compressor could be going, the expansion valve could be failing, the condenser could be clogged. Someone could have charged it with a bunch of system oil. Who knows. You will have to read the pressures and conditions and chart them to figure out the problem.

 

So, I went to my local Honda dealer to have them recharge my AC system. I figure Honda trained mechanics cannot screw it up any worse than the local Sears ac mechanic. The problem was the Sears ac recharge amount of 16 ounces is not enough. I think the spec for the 99 SI is 20 ounces or something like that. Honda recharged it to factory spec and now its a freezer. It blows 43 degrees now. Problem solved. Yes the dealer was a bit more but they did it right.