74 riviera, the ac works great in city driving but on hwys it does not cool, i think, builds up to much pressure and chokes down the compressor, bogs the engine down, its an on off thing, ac has been working great for several months since work as done on it, what should i look for stephen
Are the pressures correct? At highway speeds the pressure will drop. It could be cutting out the low pressure switch.
Per Briz's comment, could need charging...but I don't think that the "bogging down" is AC related. Sounds more like it's getting hot and losing HP than the AC being an issue. If the car gets hot enough, it will affect the AC. Do you have gauges? Can you somehow tell how hot the engine is getting?
