Hey Guys,

The wife's 2001 Venture has a hissing sound in the passengers dash area when the A/C is running, blows air a little cooler than ambient. Threw the gauges on the system and got 20 on the low side and about 150 on the high side at idle on a 75 degree day. A little low, Wally Mart for the 16 oz can and throw that in there, now 35 on the low side and 175 on the high side at idle and it blows cooler but not cold air (exact temp unknown cuz the wife use my A/C thermometer to cook a turkey and now I can't find the damn thing).

The F@$%ing hissing noise is still there, and also when I watch the gauges and bump the engine speed up to about 1500 the low side pressure drops to about 20 psi.

I know the hissing is NOT from an evaporator leak, hissing this loud would drain the system in about 2 minutes. I am thinking restricted orifice tube.

Any ideas, suggestions, helpful hints...... I don't even know where the orifice tube is on the Venture? Any help would be greatly appreciated.

Any special tools needed to replace the orifice tube, I have access to gauges and a vacuum pump?

Oh yeah, this is a dual system with rear air. Rear systems blows cool not cold air also.

Thanks

Sparky

Orfice tube is usually in the connection at the condenser outlet. Maybe you have a vacuum leak. Doesn't the Venture use vacuum mode switching? Do you have the hiss when you put the mode in Defog (A/C still runs)?. Also does it hiss if you have it on vent and switch off the A/C?

I have the same hissing noise on my '02 Silhouette. The first time it was noticed was when the R134 was low due to a cracked condenser. After replacing the condenser and evacuating the system, I charged it up. Now I only get the hissing noise at idle speeds. If I bump it up to around 1500 RPM, the noise goes away. I also was thinking a problem with the orifice tube. I have the same hissing in defrost mode. I haven't had time to work on it further.