02 grand cherokee, ac was low on 134 so i added some,now there is a hammering sound like a machine gun going off!!,even when you shut the car off it continues for a little while,it actually shakes the low side line when its running,i did a kinda quick search and it would seem that people who have had this problem replaced the expansion valve and it cured the problem,i would like some comments from a AC expert,there has to be some on here!!,the fact that it continues after the car is shut off for a while makes me think its NOT the compressor,and yes it will do it when the freon is a little low as well as high,i just want to be sure im not on a witch hunt when i tear into it!!
thanks in advance!!
Butch