Strange Sound from Air Conditioning

[Falkon]

2004 Grand Cherokee. Just had work done on blend doors so I assume they opened up the A/C system. Now whenever the A/C is on I hear a sound that can best be described as water running through a pipe. You know the way it sounds when the pipe runs through a room yet the water is turned on upstairs etc.

And now it does this only once in a while, about every 30sec to over a minute. A slight whooshing from the evaporator area behind the dash, then quiet. It makes the sound louder and longer if accelerating. A/C works great cold and all. This starts happening as soon as the car is started so it's not frosted up. Kind of like pressure builds and releases every once in a while. It's not so loud that the radio wouldn't nearly drown it out. Any Ideas?

I'm afraid to take it back to the dealer again. Every time they have worked on it something else has happened. This thing and a creaking noise (now fixed) from the mode doors when blend doors were fixed. Then they worked on the trans and left the fluid 3 quarts low. Still wonder if driving 1000 miles that way damaged the trans. It hesitates a second or two when shifted into D or R SOMETIMES. Not always. Then engages really hard. Of course each time it was checked they said trans is OK. Any ideas on this one ?

 

[SteelHeadz]

If the HVAC was pulled off the vehicle to be serviced, i would assume that the "whooshing" noise your hearing maybe an air pocket in the cooling system. Check the radiator coolant level with the vehicle Cold and parked in a level surface. If it is low, the system was not properly purged.. To do this, follow the upper radiator hose to the engine side. On the top of the radiator hose mounting elbow is an allen screw. Loosen this until some of the coolant comes out along with some air.Snug the bleeder and start the engine with the radiator cap off and watch the coollant level carefully and keep it topped off as it reaches the normal operating temperature. BE VERY CAREFULL as the engine gets hotter the coolant will be scolding hot as well. When the t.stat opens up, loosen the allen screw again just enough to let the air out. If there is no longer any bubbles coming out, tighten it and top off the coolant then re-install the radiator cap and top off the reservoir. As for the shifting concern, It is considered normal for a slight delay shifting from reverse to a forward gear on a 45RFE or a 545RFE transmission. After the vehicle has sat for 8 hrs. or more , it is also considered normal for these transmissions to have a delayed engagement up to 6 seconds or less and is also contingent on the ambient temperature. The harsh engagement could be caused by a broken spring in the accumulator, however, since it's only evident "Sometimes", i would rule out the broken spring but instead check the line pressure when the concern is evident. There are multiple verifications that needs to be addressed prior to condeming a component in the transmission. Things to consider: Is the seal on the filter neck properly installed, was the CVI (Clutch Volume Index) Checked, was the relearn procedure followed after the trans repair?.. All this are variables that may contribute to a concern but not limited to , either way, the use of a proper diagnostic scan tool and the knowlege of troubleshooting this issue is required.