AC cool, not cold...

[oldmako]

On a hot day, it takes 10-15 mins before my car is comfortable. (85 300CD) I recently bought it and have no info on the maint history of the AC.

It has been converted to r-134.

Would it be considered idiotic to simply add a can of freon in an attempt to bolster the cooling capability?

[97 SL320]

You really need to check pressures before adding more freon, more does not equal better cooling.

If the compressor is getting weak, cooling capacity will be reduced. If the expansion valve is restricted cooling capacity will be reduced.

Does this have the GM R4 compressor? Someone on the Diesel side of things makes a conversion kit to a more modern compressor if yours needs changed.

[rocky raccoon]

If after checking pressures you need a top-off, use the right stuff.

I too have converted to R134 in my '83 coupe and now wish I never had. It will never be as efficient as the original R12 even though I changed compressor, expansion valve and all hoses and o-rings. I think the only thing that can make R134 work well in our old dogs is a good efficient cross-flow condenser. Maybe some day.