I notice few days ago after parking the E150 in the garage I hear a sound from the back I taught I bump on something but the vehicle is fully stop when I hear that sound. After observing it for few days, the sound is coming from rear driver side(left). I think near where water is dropping when A/C is on or near the rear Evaporator if i'm not mistaken. I can hear the sound whenever I turn off the A/C after using it for few minutes.. I'm not talking of the vacuum sound in the vent when turning the A/C off. It sounds like a can popping or ABS brake releasing and like someone kick/punch the vehicle. I just recharge the system few weeks or a month ago. Now I notice the A/C is not blowing very cold air anymore. How to fix and detect the leak? I read a post somewhere in the forum not to use R134a with sealer. How can I fix it? I also remember that the Heater is not working when I got the vehicle. Pls post a guide! TY!

 

Sounds like the evaporator freezing up then when you shut it off it thaws out. Its either low on r134a or restricting air flow(check for cabin filter).

 

Do Econoline have cabin filter? Pls send me a guide how to check it.

Is it safe to use the r134 w/ sealer? What is the best r134a brand to use?
I went to the dealer here and told me that I should replace the evaporator to fix the leak but he did not even try to check or find where the leak is.

 

I don't know if vans have cabin filter. Just a suggestion. If a dealer suggesting buy a evaporator, It must have a leak. I don't work on car air conditioners. just giving suggestions. They sell a gauge at auto parts stores. You can try:check temp coming out of vents. Let it run for about 5 minutes and check temperatures coming out. I'm assuming it should be 15-20 difference ambient temp minus 15-20 coming out of vents. If its 70 degrees outside you should about 50-55 coming out of vents.