AC question - noticieable engine drag?

Driving on the highway with the A/C on, I could feel a quite noticeable drag on the engine when the A/C kicked on and off. Is this normal? Also, there was a hissing, or exhaling sound (kinda like someone breathing out while sleeping deep) about every 30 seconds that I could hear in the passenger foot area. The air did a decent job of keeping it cool I guess, I have not had a convertible before, so I don't know how cool the car should be able to keep it. Thanks!

Sounds normal to me. The faint hissing noise is just your compressor turning on and off.

yeah my 318 has absolutely NO power when driving with the AC on (insert 318 joke here) put thats normal as it is adding more drag to the pulley system.

Me too... when I'm at a dead stop my car feels like it wants to stall... lol...

Originally Posted by jsdugan

Driving on the highway with the A/C on, I could feel a quite noticeable drag on the engine when the A/C kicked on and off. Is this normal? Also, there was a hissing, or exhaling sound (kinda like someone breathing out while sleeping deep) about every 30 seconds that I could hear in the passenger foot area. The air did a decent job of keeping it cool I guess, I have not had a convertible before, so I don't know how cool the car should be able to keep it. Thanks!

There is an intake vent under the dash in the passenger footwell area. There's a small fan that pulls air in there to sample the air temperature on the passenger side for temperature control. To change out the AC microfilter you have to pull down the underdash covering and pull out this intake vent. If you don't get the vent assembly reseated completely during reinstallation they can be pretty noisy.

While a bit of an overblown problem at times, having a bad VANOS (or one functioning at less than optimal levels) may increase the "bog down" you experience with the AC running. It's a cheap, but very time consuming rebuild process.

Thanks for the info guys, I feel a little better about the power drain. I will check up under the dash for the noise, and I will do a search for the VANOS thing. I just got the car, and I am not sure maintenance was kept up real well.