Hi guys

I have taken my van into the local GM dealer and they did tests and added refrigerant and dye.

The test results say no leaks. But when I start the air con it makes a loud hissing sound and not very cold air coming out.

I am sick of being ripped off by garages so does anyone here have some idea before I take it back again for them to look at?

When I called them they said oh well there must be a leak then but they were supposed to have checked that in the first place.... GRHHHHHHHRRRRRRR