Automotive Air Conditioning Information Forum (Archives)

rojeho on Thu May 10, 2012 11:30 PM

Year: 1992
Make: BMW
Model: 318i
Engine Size: 4
Refrigerant Type: R134a

A follow-up to another question that I posted. I know that I have a leak big enough that I can hear a slight hiss and it won't hold vacuum at all. When an intake manifold has a vacuum leak you can spray cleaner and when the engine smooths out you've found the offending spot. Is it possible to do something similar with the ac system?

GM Tech on Fri May 11, 2012 6:17 AM

NO...but use a rubber hose to your good ear and scan the areas while it is hissing- Turn off all other background noise and you will soon locate it.

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

Cussboy on Fri May 11, 2012 11:12 AM

A leak that big might make it iffy to even use soap bubbles....do as detailed above. Also, when you get your hand or the rubber hose close to the leak, will likely alter the pitch or volume of the hiss.