My daughter spent about $900 with a reputable shop to get the A/C working on her 1600 twin cam Civic hatchback of about 1991 vintage. But as soon as she turned the new unit on, the engine began to overheat. Any suggestions would be welcomed.

 

Be sure that both fans work. In a stock setup (there were no stock twin cam 1991s in the USA, so it's not clear exactly what she has), both fans should run constantly while the compressor is engaged or if the engine gets hot.

If it's not a fan problem, overheating with the A/C on also means that it's also really close to overheating with the A/C off. Check that the radiator is full (with the engine cold). The radiator may need replacing.

 

Thanks. I've told her to check. Where are the fans? I'm sure one is in front of the radiator coils (actually, behind). Somewhere on something somewhat official, I read that one in nine Civics that year had the twin cam, four-valve engine. Hope that
Ames hers a valuable rarity. Makes me really wish I'd bought the Lotus 61 roller in 1981 rather than squander all my money on what turned out to be an unsuccessful business venture.